Engineering Our Freedom

Evolution of 3D Printing

2013-03-16T05:37:00.000Z

3D printing, that amazing technology that has recently grasped the media's attention, evoking comparisons to Star Trek's 'replicator' that could assemble any known object out of its basic molecules. Behind all the hype, what can it do, and will it really change our world?

Early History:
'3D printing' as it is known today actually spans several similar manufacturing methods that were a natural evolution from CNC machine tools developed in the first half of the 20th century CE.

A manual wood lathe.

Numerical Control made old subtractive manufacturing tools (ones that cut material away from a plain starting block in order to reach a desired shape), such as lathes less prone to operator error, first by use of 'cutting by numbers' (where operators would dial in exact coordinates on a gauge to cut holes and file between them, rather than attempting to guide a cut through a straight line or curve by hand), followed by punch-card fed computerised motor controls, and eventually full digital control by microelectronics that can now be fed instructions derived directly from a CAD model or drawing.

A CNC lathe.

Those advances took production processes that were seen as a highly skilled art or craft and allowed them to produce highly standardised replaceable/interchangeable parts, and so cut the costs of repairing any given product. Most importantly, CNC mills that use an X-Y table and a cutting head that moves up and down (in the Z-axis) laid foundations for most 3D-printing technology. While these milling machines have been used heavily in recent decades by industrial giants in China, for carving out mould plates with which to injection-mould plastics into all kinds of things that people often don't need, some creative minds wondered whether we could perform that process in reverse - using a toolhead moving in 3 dimensions to deposit material rather than taking it away. Thus, through the 1970s and '80s there were several different methods patented for building up a solid object in thin layers, and a rapid prototyping industry was born.

Stereolithography (photo-polymer resin) 3D printing.

Stereolithography was patented by Charles W. Hull in 1984, who went on to found the first rapid-prototyping giant, 3D Systems, in 1986. SLA involves projecting cross-sections of an object onto the surface of a pool of photopolymer resin using a UV laser, in order to cure the resin into a solid object. This process has resulted in parts with extreme precision, with layer thicknesses several microns thick, so that they make excellent visual prototypes and artistic models, but the material used is brittle, expensive and difficult to recycle.

Fused Deposition Modelling (thermoplastic extrusion) 3D printing

Fused Deposition Modelling was patented by S. Scott Crump in 1989, and the next year he commercialised the process when he co-founded the company Stratasys with his wife Lisa. FDM involves repeatedly squeezing lines of recyclable molten thermoplastic through a fine nozzle onto a work-surface. Initially this process resulted in a rough surface finish and quite fragile objects, but numerous advances have been made in recent years to improve on this.

Selective Laser Sintering (one type of powder printing)

Some other 3D Printing methods have involved binding powders together by various methods, such as Selective Laser Sintering, where layers of powdered material are spread out repeatedly in a box and melted with a laser so that their cross-section sticks to the layer below, and the type of inkjet & powder 3D printing used by Z Corp, where an inkjet head drops a binding material onto the layer of powder spread out below it.
These methods allow a great variety of materials to be used, and also eliminate the problem of printing sections that overhang the print-bed when using FDM in Earth's gravitational field, which can otherwise sag if not solidified rapidly enough, although that particular problem has more recently been solved within FDM by using a second extruder to lay out a soluble support material such as PVA, which can then be easily washed away from the printed object.

Enter the Replicators:
In 2005, the RepRap project was founded by Dr Adrian Bowyer and some of his students at the University of Bath. Its stated aim was to produce a "Replicating, Rapid-prototyping" machine, i.e. a 3D printer that could produce some or all of the key components needed to assemble an exact (or better) copy of itself. With a keen interest in biomimetic systems (ones that mimic natural biology), Adrian's hope was that by allowing these machines to self-replicate, given a user with a supply of basic industrial materials and fittings, they might replicate exponentially and hence create an exponentially increasing production capacity, while given some human creativity, they might also evolve into more advanced forms. Both of these hopes have turned out to be true since the project began.
Within two years the first full design was complete, named after Charles Darwin, one of the founding theorists on biological evolution, a trend which continued through the project. It was based upon Fused Deposition Modelling, but since Stratasys had trademarked that term, the project coined the general term "Fused Filament Fabrication" for their production method. Another year passed and the first 'child' of this machine, fully constructed from parts printed on the first 'Darwin' along with standard fasteners, started printing a 'grandchild' part in May 2008. By September it was estimated that there were at least 100 copies of Darwin 'in the wild'.
In November, one of the RepRap contributors, Zach Smith, launched a website called Thingiverse, which allows people to upload Free-and-Open-Source digital designs for others to print. At the start of 2009 he then co-founded a startup known as MakerBot Industries with his friends Adam Mayer and Bre Pettis. Their company would go on to take a large share of the US market for hobbyist 3D printers by using cheap laser-cut parts in their kits, combined with clever marketing, and received a warm reception from the 'maker' community for their supporting website Thingiverse, though they suffered some controversy in later years when they took $10-million in venture capital investment from The Foundry Group, filed a patent on one of their designs, and were recently criticised for releasing a closed-source/proprietary printer based upon past open-source innovations, which was even criticised by Zach Smith who has since left the company.

By October '09, the second full design for a RepRap was released, named after Gregor Mendel, and its stark improvements in design were detailed here by Edward Sells:

In the next two years there were several more variations made upon this design, including a miniaturised version named after Thomas Huxley, a greatly simplified and low-cost version designed by Josef Prusa, plus many small modifications and one-off 'RepStraps' (coined from 'bootstrapping') that adapted those designs to locally available materials.
By September 2011, the quality of a RepRap Prusa Mendel had surpassed that of some Stratasys systems:

Come forward to 2013, and there are dozens if not hundreds of full designs for DIY 3D Printers listed on the RepRap Project Wiki, Github (including Free and Open Source Software on which to run a printer), and on Thingiverse, while several alternative ways to host free 3D-design files have been springing up, such as the 'Physibles' torrent category on The Pirate Bay, graphical page templates for MediaGoblin and Github, and easy-to-use sites like CubeHero and Fizzybles.
Some notable designs include the Printrbot designed by Brook Drumm, who intended for it to be so simple and low-cost as to enable putting one 3D printer in every school, and easy enough to construct that any interested students could build their own from parts printed on a school machine. A designer calling himself Whosawhatsis has been redesigning this to be more robust and naming its successor after Alfred Wallace.
The MendelMax design is known for being one of the most rigid RepRaps, using aluminium extrusions for its frame, as are used in some commercial CNC machines, and building upon this solid design, the Colorado-based company Aleph Objects released a printer that was the first hardware product to receive the 'Respects Your Freedom' certification from the Free Software Foundation.

The Current State of 3D Printing:
In May 2012, the first major statistical survey of the 3D Printing community showed up many interesting points, including this distribution of printer types, showing that for sheer volume and quality for a given price, nothing could beat RepRaps, which had only been around for a quarter of the time of the professional rapid-prototyping companies, and that PolyLactic Acid, a biodegradable polymer made from plant starches, is now the most-used 3D printing material.

RepRap For The Win

It should be noted that 3D Systems had spent much of the previous two years buying up 24 small 3D printing companies in order to become the largest 3D printing company in the international market, but that only lasted until Stratasys and Objet merged to form an even larger competitor.
More recently, Joseph Flaherty of Wired reported on 10 existing patents that may stymie new business startups in the 3D-printing industry.

Nevertheless, various extremely high-tech and low-environmental-impact innovations based upon 3D Printing have been brought out in the last couple of years, which are set to evolve several industrial sectors and ways that we solve problems.

For example, a team in Glasgow University have been developing 3D-printed chemical reaction vessels that allow highly complex drugs and other organic molecules to be produced from basic ingredients, by customising the paths through which they interact, and so control the duration and nature of those chemical reactions, to bring about a maximum amount of a desired product.
'Bio-Printers' such as those produced by Organovo are getting close to being able to produce artificial yet biological and fully-functional human transplant organs, tailored to the needs of the recipient. Last year they were already printing lengths of blood-vessels that could be used for the likes of cardiac-bypass operations. Not only could this ease the strain on our medical system's use of organ donations for life-saving or reconstructive surgery, but could also reduce the risks involved with it. Some DIY versions are already popping up.
Contour Crafting, a type of 3D printing similar to FDM/FFF but using ceramic materials such as clays or concretes, has been suggested as a method for producing dwellings with high material efficiency both on Earth and on expeditions to Mars or our Moon. Open source versions of similar technology have shown to be capable of printing some very intricate structures in clays:

The capabilities of commercial CNC machines and 3D printers are reaching amazing levels, with Objet's new '1000' printer being capable of creating objects 1 metre long and printed out of 14 different materials. Meanwhile, initial results are being released on an open source powder-printer prototype and an open source 3D scanner may make it easier than ever to precisely reproduce museum items without damaging them.

What this could mean for the future:
There has been much debate lately about the significance of 3D Printing and its possible effects upon human industry. While it presents a radical expansion of production capabilities, critics have been quick to point out that 3D Printers may not find a 'mass market' (i.e. to see one in every wealthy home, as with lesser robots such as inkjet printers, washing machines or microwave ovens), because an average working person doesn't know how to use CAD software or have enough experience with mechanical design to create their own functional novel items, or because the price of small plastic parts will always be lower for mass moulded parts, and the market for novelty items is very small. However, these critiques turn out to be awkwardly myopic once you realise they are confined to a belief that a capitalist market system can be sustained indefinitely.

Many people have been looking at the available data on our global resource stocks and industrial output, and have come to a conclusion with extremely little doubt, that not only is the current paradigm of 'economic growth' impossible to continue in light of our current fossil fuels and other resource stocks, but even if we were to stop increasing our consumption right now, our current use of natural resources would crash into a wall of disappearing non-renewable resources (or slow-renewing ones like fossil fuels, which took millions of years to form, and little over a hundred years for us to burn halfway through them), and those high-tech gadgets that western societies habitually build to shoddy standards and then throw away, would be available to even fewer people.
It is imperative now that we not only use renewable energy and recyclable resources, but we must pay more attention than ever to the first of those three R's often used as a municipal recycling service slogan - Reduce, Reuse, Recycle. We must first reduce our cyclical consumption of natural resources to almost half of their current levels, and begin completely phase-out any linear use of non-renewable or non-recyclable materials. As Dr David MacKay so astutely pointed out:
"Have no illusions. To achieve our goal of getting off fossil fuels, these reductions in demand and increases in supply must be big. Don’t be distracted by the myth that “every little helps.” If everyone does a little, we’ll achieve only a little. We must do a lot. What’s required are big changes in demand and in supply."

The same goes for resources more tangible than our energy supply. It doesn't matter if you re-used a plastic bag from a supermarket, those things are difficult to recycle and tend to result in an inferior material that cannot be used for its original purpose (i.e. they are downcycled, not recycled). I have said for several years that if regulating a market via 'representative democracy' were ever feasible, we would have long ago seen a blanket ban on non-biodegradable plastic films for food packaging, and on any use of those plastics where a recycling system was not in place. However, if a 'free market' could really bring about rational use of resources on its own, then we wouldn't have to tell these suppliers not to do such irrational things in the first place. Yet we do have to, and mindless mass consumerism for the sake of cultural or advertising whims, as Edward Bernays encouraged so well, has to stop if we want to survive as a species.

"The Earth is the only world known, so far, to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment, the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we've ever known." - Carl Sagan, Pale Blue Dot: A Vision of the Human Future in Space, 1997 reprint, pp. xv–xvi

Luckily for us, there are far better methods of organising consumption so as to increase our material efficiency such that we meet people's recurring needs not with half as many resources as we do today, but with more like a tenth of that input. One model to meet this need, which has been gaining popularity recently, is known as 'Collaborative Consumption'. Simply put, this involves a community, or individuals within one, acquiring tools that people may need to use infrequently, such as vacuum cleaners, high-resolution cameras, performance equipment, et cetera, and borrowing them from each other while sharing the cost of maintaining them.
There is also a type of institution that has done this successfully in the background for centuries, contributing enormous amount of value to human culture and technology - we call these institutions Public Libraries. In western nations today, they provide a lot more than just books, yet there is still so much that they are lacking.

Every parking lot packed with cars awaiting their registered keepers, every white-collar house stuffed with dusty sports equipment that youth clubs could use, and every new-year's dumpster filled with discarded plastic toys from a previous year's Consumptionmass, is a testament to the possible abundance of human productivity, squandered by a system based upon fear and status.
Yet islands of trust are appearing within that ocean of fearing one's neighbour, even if these examples do begin with locks and keys on shared items, just as public libraries within this monetary system regularly place RFID tags in books, and corresponding alarms at their doors, to work around the neuroses generated within that marketplace. Examples include the US car-sharing company Zipcar who as of last month were sharing less than 10,000 vehicles between over 777,000 people, and the Vélo'v service in Lyon, France, where from the years 2005-07, 16,000 journeys per day were completed between 343 stations, with around 4,000 bikes, with the service reporting having over 52,000 subscribers at that time.

These systems form an important transitionary step in a trend towards a situation that has been advocated by groups such as The Zeitgeist Movement, termed 'Access-Abundance'. In such a situation, communities would produce a small number of such short-used tools compared to the number of users, yet more than would be needed at any one moment, to the highest material standards possible, in order so make huge long-term savings in time, space, energy and raw materials. Such low-scale and localised consumption is ideal for the application of 3D printing, which would be able to not only create an infinite variety of ergonomic customisation for local users' needs, but also create replacement parts on the same day that they are needed, instead of keeping warehouses full of spares and waiting a week for them to be delivered. That goes even without mentioning that repair is better, and that the collaboration that comes with the use of a local hackerspace or tool library yields its own fruits in sparking people's creativity.

In summary, a wholesale evolution in production can be provided by 3D Printing, it can drive costs of production towards zero, and not only is it completely possible, it's completely necessary.

Winter Finishing Touches on a Windbreak

2013-03-10T00:34:00.000Z

So, for a well-overdue update of what's happened this winter of 2012 to '13, some of the useful things I learned, whether hard lessons or delightful ones, are as follows:
While I saw most of the annual plants that I put out demolished either by slugs or sheep, and only got a few halfway-decent fruit from Alpine Strawberries in their first year of planting, the only significant food crop that I was able to grow in spite of all that and the mostly unfettered hard winds came from a very unexpected place. A bunch of radish seeds that I had sowed on compost mostly next to a plum tree and a few other spots were taking off very healthily.
I had mistaken them for turnip plants at the start of autumn when they brought out lots of pink flowers, but upon pulling one out to thin them down, I discovered that not only were they radishes, but the root growth was utterly terrible, no larger than a single chick pea and very woody by the time the plant was in flower, so I left them to self-seed, until I got this surprise as their flowers fruited...
It turns out that radishes grow not only an edible root crop, but also some tasty little seed pods (only roughly similar pea pods in shape), which were very nice when sliced into salads.

See the root of the plant that I plucked these off of; it was tiny in proportion to the above-ground part of this plant, although I shouldn't really be surprised when growing root crops in rocky soil.

I've also confirmed that local bumblebees love these Fiddleneck flowers:

Most of these were already setting seeds, but there were still plenty of flowers to keep the bees fed, and the sage that I planted out at the base of these green-manure plants, should benefit next season from the nitrogen that they fix into the soil.

Once I uncovered them from rampant grasses, I found that the Nasturtiums I planted out had been chewed up by slugs a lot, but they were still growing strong.

I cut clumps of grass with a knife here to mulch around them, but the nasturtiums should eventually out-compete the grasses anyway.

To have some fruit bushes within the westward wind-break hedge, I tried sticking some more Blackberry cuttings straight outside, but this time making sure to use thick, 2-year-old canes instead of the shoots that I had tried to use before.

With the shoots trimmed back, this should hopefully take root strongly and sprout shoots next year.

I also took cuttings of some very successful local Gooseberry bushes, treated their base with a bit of powdered seaweed that I was told is supposed to encourage rooting, and shoved them straight into fresh compost.

As I write this, these all seem to have taken root, and are now growing spring leaf buds.

To complete the windbreak around this pioneering patch of woodland, I first started by getting hold of a very useful plant that should grow very quickly and spread via its root system.

Not only are Bamboos some of the fastest-growing plants in nature, followed closely by some species of Cannabis, but this Golden Bamboo in particular grows edible shoots in spring that are said to be palatable even while raw, and like many others it will eventually produce functional pipes.

Later I planted a few Hazel and Sweet-Chestnut trees, which are supposed to be very hardy to strong winds and have historically been used in coppiced hedgerows, so even if they don't produce a lot of food they will serve a structural function and also provide some regular firewood.

A bundle of baby trees rescued from a housing estate being re-developed. The darker brown-barked ones are chestnuts and the lighter green-barked ones are hazels.

Indoors, I lost a whole tray of Black Mulberry seedlings simply by forgetting to water them over one sunny weekend that dried their compost out on a windowsill, while I have still been completely unsuccessful at germinating Siberian Pea Tree seeds, so now I've been cold-stratifying another set of dormant seeds in our fridge over winter, to give this another go (I didn't use all of the seeds that I got at once, knowing that I would probably mess up with some of them on my first attempt).

Here it seems that the cutting I took of a plum-tree shoot failed to take root, although that was treated with the same seaweed powder as the gooseberry cuttings. On either side are Sugar Maple seedlings, one of which, along with the Oleaster at the back, is now suffering from a fungal infection long after this picture was taken.

Of course, to establish a highly productive food-forest, plenty of nitrogen-fixing pioneer shrubs are needed to support the growth of canopy trees.

The potted Elaeagnus x Ebbingei that I planted out seems to be recovering from root shock, with several leaves growing at its base, but the E. Pungens isn't showing signs of life.

Meanwhile, some E. Angustifolia seeds that I planted indoors have had some very mixed success. Six of them have germinated out of a couple dozen at most, but their drip tray was knocked over by a local cat that got in at one point, and of the ones that I managed to recover, only 3 have not died due to shock or fungal infection. With this difficulty establishing various potted, cut or sown Elaeagnus shrubs, I have grudgingly turned to our thorny native Gorse to see whether cuttings of that will have any more success.
This time around I remembered to do something that didn't occur to me before, which was to steep some of our plentiful White Willow bark in hot water so as to make a tea that encourages root growth, and left cuttings of gorse in this overnight.

Those vicious green thorns actually make a healthy winter livestock feed if you grind them up.

The north bend of the windbreak now looks a bit like this after pruning most of the trees:

Yes, that is actually a whole window + frame mulching down some of the grass in front of a baby crab-apple tree (I put a couple of those in to aid pollenation of other apple trees).

A couple of neighbours have been doing some serious modification and renovation of their old houses round here, so I also have some scraps of concrete slabs/bricks that can be used to compress grass down for areas to grow on, far more effectively than I could do with cardboard last year. I have shoved small boulders around on the grass here a few times and noticed that compression counts more than a lack of light when breaking down grass to give a bare patch of ground to grow on.

My forest-garden plan now looks like this:

Finally scanned in. With a rough U-shape to the treeline, this can now function as one end to a larger stand of trees that could shelter the community's little-used ground from harsh winds and make it easier to grow herbaceous-layer crops in a wide clearing.

The "?" mystery plant at position 4T is this next one, which I got off a neighbour who wasn't sure what it's called either.

I'll also put an entry about it here. I'm not certain, but that also looks like some Pampas Grass has sprung up right in the corner, although it looks a bit stunted.

This mystery cane-plant has a growth pattern somewhere between bamboo and hazel, in that it grows a few trunks that branch out moderately, but its shoots are completely hollow inside in order to pass fluids through, while older branches have a straw-size hole through the middle of them. A bit of dead old growth that I have found on another plant was extremely lightweight and made excellent kindling for a fire.

I have also found an ideal species to fill the woodland niche of 'climber' up here, a plant known as Tara Vine, or Kiwi Berry, which produces a small hairless kiwi fruit about the size of a grape, and most importantly grows in some very cold climates. I am currently chilling some of their lightly dormant seeds in the fridge along with the others.

Over the rest of winter I've been preparing several other projects that are partly linked, such as picking out usable boards from old pallets to build a small beehive with, which can both aid fruit pollenation and provide a couple more useful natural products in the form of honey and beeswax. I've gathered up a can, pipe, sand and clay with which to build a mini-furnace and do some sand casting, which will enable me to make some very strong joints and possibly custom aluminium heatsinks for the wind turbine that I'm developing, and possibly even build a reused-motor lathe. I've also been trying to figure out how old sock knitting machines work in order to make an Open Hardware version of one. Take that as a teaser for anyone who wants to read a bit about what I'll be updating on soon alongside a couple of theoretical pieces.

Prep to Prototype

2012-11-04T00:12:00.000Z

On the way to prototyping my ducted wind turbine design, there have been a few silly setbacks as usual with 3D printing, and that's before even mentioning how awkward part sourcing is when no one supplier ever has everything you need, and I end up forced to waste postage on a few orders just to get electronics to build a data-logging controller with. Also I'm writing this for a second time since Blogger ate my post by erroneously bringing up a blank workspace one morning after I was 90% through this post, and saving over it before I could close the tab. Unlike those lovely etherpads, there was no writing history to revert back to.

I've brought this reprap to its working limits in a couple of different ways over the last few weeks, firstly with a bespoke drill-guide that I made in a similar way to the dremel cutting kit only super-sized so as to allow a cheap hammer drill to make nicely perpendicular holes in the absence of a drill press.
A trouble with this print is its huge width compared to the narrow surface area actually in contact with the print surface, which meant that, being a PLA prototype, it could barely adhere to the kapton-taped surface strongly enough to stay down. When some overhanging edges started to curl up slightly, the resulting light collisions with the extruder head caused the wider of two parts to start lifting up off the printbed with an audible crack. I found a quick fix to keep that part in place before the whole surface dislodged.

Bulldog clips and small allen keys were handy, so they held the part down.

This print was eventually successful, but not before another limit in size surprised me.
There is a slight complication in the build volume with this triangular-prism shaped frame, depending upon how the extruder is fitted; normally the greatest available Z-height is clearly limited by when the tallest part of the extruder reaches the top bars, or in my case when part of the extruder motor reaches the control-board mounting plate.

Above centre: on the top layer of the smaller part of this print, 75mm up, the motor passed so close to the frame that I could no longer see the gap. I removed one of the board's mounting blocks at that corner when I saw it get close, or it would already have collided.

This complication arose since the extruder motor was mounted at the positive end of the x-axis, so that when it was at positions close to that end of the x-axis, height was limited by the extruder motor potentially moving through space occupied by one of the frame bars at 60°, and because there currently isn't an option in host software such as printrun to only allow prints to fit within a space more complicated than a cuboid.

When starting to test I learned a simple lesson about the J-Head Mk.IV hot-end: don't ever forget to turn on a cooling fan when running PLA through it.

Result of no cooling: molten PLA worked its way up to plug the heat barrier.

Thankfully this hot-end is very easy to dis-assemble, and as soon as I dug a bit of that PLA out of the top, by removing a chunky set-screw from the end with an allen key, the remaining clogged PLA practically popped out with a still-warm PTFE sleeve.

That black set-screw I think is about M8 size, and is a clever way of keeping the sleeve compressed while having a gap for filament to pass through.

So I gave printing on cardboard another try, this time trying to print a plant-holding part of my rotary hydroponics kit, but something else went wrong in the first layer when it seemed that the hot-end couldn't stay up at melting temperature.

Adhesion to inside-of-cereal-box cardboard was initially great until this.

After testing the heater and checking around with a multimeter to figure out why it was completely failing to heat up anymore, I realised that an electronic part had blown out that I would never have expected to do so before.

This nearly-new wire-wound heating resistor that came installed with the new hot-end somehow ruptured under normal operating conditions. 'W21 5PS' is printed on the opposite side.

While it's a cheap part to replace, I decided that I wasn't going to wait over a weekend to get a new one, so I tried taking the working resistor out of my old hot-end that was still lying around for spares, as you can see it in the top-left of the last picture. On dis-assembling the old heater block however, I found out that putting cheap thermal paste on one of those resistors isn't a great idea, as it had turned into a fine grey dust that got everywhere after a year of repeated heating.
There was still another problem with fitting my old heating resistor though.

It didn't fit.

But a bit of aluminium foil quickly solved that.

My quick solution may not give a perfect fit, but at least it was back up and running so that I could continue testing PLA onto cardboard.
First I tried a wide part that would test the warping problem that I had with paper. For this I used a z-motor bracket from Prusa's Mendel iteration 2 repository, aligned flat along the build plate. I quickly saw again something else that I needed to improve in my printer:

Overhanging corners of PLA start to curl up slightly during printing.

Although I clearly needed to add some cooling to improve the quality of slight overhangs in PLA, at least the bottom surface warp wasn't bad.

Pretty good actually, very near parallel.

My solution to cooling was to hook up a fan that I'd salvaged from the case of an old discarded mac computer with some spare wire and old bolt-on PLA bushings.

Fan in foreground with another z-motor bracket cooling down.

The result of a re-test was much better:

So good that it would fit right away without any reaming.

However, the wiring for this new fan was a bit messy, being shoved into the screw terminal plug for my motherboard at one end, with jumper wires at the other end (visible above), and I resolved to tidy up some of the growing mess that was the wiring of my printer (the x-carriage fan was plugged in by a terminal strip that I turned back-to-front whenever I wanted to switch it off, while I had used a bit of screw terminal block to connect 240V mains wires to a 12V power supply, which were one misplaced hand-tool away from a nasty shock - all in all, an embarrassment) with a power switchbox using some nice chunky switches that I had lying around.

A large print of my custom switchbox design.

The print didn't go badly until the last few layers when the extruder jammed just as it was about to print some holes for the lid to hinge around. Thankfully it wasn't an exploding resistor this time, but a far easier-to-replace part.

Gregfrost's filament-guiding extruder idler ('guidler') broke between layers, allowing the filament to slip off the extruder biting point, so I designed and uploaded a reinforced version.

I had heard a little snap from that region earlier and not thought much of it, which was silly, but at least it shouldn't happen in future. It seems that printing a few wide things across cardboard isn't a very wise idea though as shown here:

Warp was pretty bad this time.

I eventually got it all together though, making my power wiring somewhat neater and making it easier to switch fans on and off, even if I still can't have the fans controlled by the old gen6 motherboard.

My electronics mounting board is now about as crowded as it can get.

After testing wide-object warp (the badly warped box seemed to be more due to adhesion loss than flexibility in the cardboard), I wanted to check out how well a tall object would print, so I placed a couple of the same motor brackets in their usual vertical alignment along with a few bar clamps to also see how well small things would do here.

I also set slic3r to code in a line of skirt material around each object individually rather than around the whole print at the start, hoping that this might help to stop edges peeling up.

The small bar-clamps turned out fine, but the motor brackets not so well due to there being enough flexibility in the cardboard for them to get knocked back and forth by the extruder head.

These definitely weren't usable straight off the printer.

Since the small parts were fine, I tried again with more, this time with the both the bar clamps and geodesic dome connector ball-joints that I had trouble with last time.

Oh, and a pulley.

That worked exceptionally well, so I did some more.

These were still great, even though the parts spanned a lot of the cardboard area, and they pop off cleanly and easily by simply bending the card after printing.

I almost forgot to mention, a friend kindly picked up a sheet of cut glass for me at our nearest glaziers (about 100 miles away), and since then print quality with PLA has been unmatched on my heated bed - adhesion is just great every time so long as the glass is clean.

Bottom surfaces are almost perfectly flat too, with a very shiny finish.

So cardboard seems to be a useful cheap temporary surface, but nothing can compare to a glass surface if you can get access to it (cost was not a problem for me - about tree fiddy - but distance was). One obvious disadvantage though is the extra weight (about 300g) that this 3mm plate adds to the y-carriage, which puts a further limit on the top speed that this printer can run at, due to risks of the plate becoming loose or increased backlash at high speeds. As a small technical point, I've measured temperature on top of the glass plate at about 65°C while the aluminium plate is at 72°C.
I've also seen people on the reprap IRC saying that they have successfully printed ABS onto a glass surface by using a thin layer of PVA (a common wood glue, which forms a water-soluble biodegradable polymer that has also been used as removable support material in dual-extrusion printers). This is great since it means that people can stop using polyimide as a print surface, since it is clearly unsustainable as a thermoset that loses its 'stick' in a number of months. There is a slight paradox there though since ABS as our main heat-resistant prototyping material is itself an unsustainable feedstock as we don't have any way to produce it that doesn't use fossil oil. This I'll be looking at solving through over-engineering soon - by sand-casting parts in recycled aluminium from PLA forms.

After all that, I've finally prepared a couple of test pieces to see how strong the mounting points in my wind turbine design can be, meanwhile it looks like the studding&nuts used as cheap leadscrews on my z-axis are finally wearing out badly from friction. I'll update with details when I have some results from strength tests, as this post has become long enough and I have a few other things to be doing first.

Practical Plants

2012-09-04T15:41:00.000+01:00

A new website launched in the last month that could be a powerful tool for Permaculture designers worldwide. At Practical Plants, produced by a web developer and a writer who are together also building an organic farm in northern Spain, the huge database provided by Plants For A Future has been forked in a wiki format, while retaining database-search functionality and adding a beautifully-styled new interface, so that hopefully the information brought from that old database can be improved by weeding out inaccurate or incomplete information and using better sources.

Practical Plants beta homepage

While PFAF has primarily focused on species appropriate for a temperate climate, Practical Plants aims to cover information on species in all climates on Earth, while adding other useful structural information to the database such as companion-planting guilds. Various practical uses of each plant will now be linked clearly to relevant parts of the plant, for instance to help people avoid eating unpalatable or toxic bits of some plants. This extra structure needs some tidying to install though since it wasn't already in the existing database structure, so why not help out when you have a moment?

In yet more exciting news about actual practical plants, a European research and development group for alternative sources of natural rubber have hit a benchmark recently as one of their partner companies prototyped natural-rubber tyres, made from two plants that can be grown in temperate climates - Guayule in warm-temperate regions and Russian Dandelion in cold-temperate areas such as here in Scotland.

Tyres from weeds by Dutch firm Apollo Vredestein :)

A great advantage of using latex from those plants is that it doesn't contain allergens like latex extracted from the tropical Rubber Tree does.

On more practical temperate plants, from what I've tried here so far, germinating tree and large shrub seeds still seems to be very hit-and-miss. After I had only two strawberry tree seeds germinate out of about a couple dozen tiny seeds sown (they were so small that trying to count them looked pointless), the first one to germinate didn't grow more than its initial pair of leaves, then later shrivelled up and died from what looks like a fungal infection.

Two Arbutus Unedo seedlings, 1 month after sowing. Re-potting the right-hand one after its original container got knocked over was likely another factor in its demise, though its growth was already stunted by then.

My only surviving Arbutus Unedo seedling up close, soon to be re-potted. Fortunately they are self-fertile, so I just hope this one is as fruitful as it is disease-resistant.

While many of the oleaster seeds that I have been chilling have caught a fungus like the sugar maple seeds did, the black mulberry seeds seem to have been luckily unaffected.

After sowing a tray of 24 mulberry seeds, 12 germinated within a week while a 13th one seems to be lagging behind weakly.

Also shown above are a new row of siberian pea tree seeds potted at the back, which I have had no success in germinating yet, and a couple of larger brown pots each with one of a few oleaster seeds that I picked out to try and curb the spread of mould in their jar. Now seems to be around the earliest that I should sow them, since the supplier suggested anywhere from 10-30 weeks, while PFAF quoted 12 weeks' cold stratification.

While disposing of monkey puzzle seeds that had failed to germinate, I noticed one thing that might have been a factor in me only getting 1/4, as there was what looked like a thick tap-root trying to grow straight down from one of the failed seeds, which of course didn't get far before it turned a right angle on the bottom of its pot, since I was quite stingy with some peaty potting mix when I sowed them.

Monkey Puzzle taproot (trimmed slightly).

Taking a lesson from this, I've now tried sowing my last 4 monkey puzzle seeds, filling narrow pots nearly to their brim with a much lighter compost. I'm determined not to over-water them and will surely report what I find.

So, more than half of the various dormant seeds that I have tried to cold-stratify in a fridge have been afflicted by mould, though all the jars used were washed with boiling water before they were soaked. My best guess is that either the seeds already had such fungi and bacteria on them when they were dropped in to absorb water, or that airborne spores entered the jars when they were opened to put seeds in and later drain water out before chilling.
Since creating an even more scrupulously sterile atmosphere for the seeds would involve a disproportionate increase in effort, this lead me to wonder whether some natural fungicide could be put in containers used for cold stratification, so I'll be testing that with my next few batches of seeds that I keep for sowing next spring. From this study, clove or cinnamon essential oils sound like promising candidates.

Every Sheep Has a Silver Lining

2012-08-16T11:23:00.000+01:00

With the Elaeagnus shrubs that suffered greatly after I planted them outdoors a few months ago, for a pair of evergreen species to lose most of their leaves during spring, I was understandably worried that they would die due to root shock and waterlogged soil.

What's more, they seemed to be completely over-run by local 'weeds' to the point that I couldn't see this one.

However, since the tiny forest garden that I'm pioneering was slightly chewed up by marauding sheep a couple of weeks ago, I've spotted signs that they are getting some strength back, and noticed some of the other plants that I stuck out growing vigorously.

This E. Pungens Maculata looks pretty dead, but on closer inspection...

I'm not sure if a couple of those new leaves were nibbled by slugs or caterpillars, but it looks like there's some life in this shrub yet.

After clearing a mess of vetch out of my way, I uncovered the other Elaeagnus.

This E. x Ebbingei, just as it was always growing stronger than its counterpart before, still has an original leaf or two at the bottom.

This one also has some new leaves forming halfway up the plant.

I hope that as a lot of the plant life dies down over autumn and winter, these evergreen elaeagnus shrubs will have a chance to flourish with some newly established growth.

It seems a lot clearer now that summer has taken its course and I've learned a bit about local flora and fauna, that the variety of life on this patch of land I'm working is a bit more diverse than the adjacent fields, which are regularly grazed down to almost nothing by herds of sheep; much more than just grass stands out here now.

Visible here are many white flower-heads of an edible perennial, common hogweed.

I'm glad to know that although my peas mostly didn't succeed as edible legumes, instead getting eaten by mice and slugs, native 'weed'-like legumes such as vetch and clover have been widespread enough to start repairing the soil on the swale that I dug.

It's not quite ground cover yet, but these two local soil-repair species are slowly creeping up the bank, and soon I'll be able to plant out some rhubarb divisions that should cover the swale in shade.

I planted this crimson clover out after it became quite overgrown on a windowsill. It didn't germinate easily outdoors like the 'fiddleneck' green manure plant did, so I'm doubtful whether it will self-seed and join those local species.

I've been surprised and pleased at how resilient some of the globe artichokes that I've planted out have been. They should be successful in this region since they are a type of thistle, and local thistles do famously well here, but some of these have managed to survive through quite a bit of damage from herbivores.

Although practically none germinated when planted straight outside, these two globe artichokes (light green plants at top) that I stuck out as quite small seedlings have survived repeated slug attack.

After an artichoke I stuck out near here was eaten to a stump, probably by a rabbit, I planted the bottom-left one with half a 2l PET bottle for protection, cutting the neck into strips to anchor it into the ground. Since then the top-right one popped up, which I guess was a seed I planted months ago only germinating in summer warmth.

I'm not certain what these are, but given that I sowed radish, squash and turnip seeds in this area, I think they are most likely gold-ball turnip plants. Although turnips usually have yellow flowers, I have seen some with purple.

Suspected turnip plants on the right (fiddleneck and hogweed on left).

The tree line is also now more closely approaching Mollison's recommended ideal open-to-equator horseshoe-shape windbreak that I'm trying to mimic, with the addition of a couple of very young crab-apple trees bought for a few quid each at a local summer fair.

First crab-apple planted between the plum and downy birch. These are usually brilliant for pollenating other apple trees, and have a high pectin content useful for making jam with other plants such as rhubarb.

Second crab-apple tree in the northernmost corner of this plot. They are both so short that they should have no trouble with wind while establishing roots, what with the fenceline and all the hogweed around them just now.

Back inside there has been a bit more success with germinating tree seeds. While I only have 3 strong-looking scots pine seedlings now surviving out of well over a dozen seeds that I tried to sow in previous weeks, the first couple of strawberry tree seedlings have popped up when I was beginning to think that none would.

Left seedling took a little over 2 weeks to germinate, while right one took just over 1 week, after both seeds had been cold-stratified for ~10 weeks.

Meanwhile I scraped a skin of moss off the pots of failed pine seeds and re-used the compost underneath to sow some sugar maple seeds. After 4 months cold-stratifying at the back of a fridge, most of them had some white fluff on their surface from a mould that got in, which I carefully wiped off before potting them. This time after watering the seeded pots I sprinkled a thin layer of dry compost over the top in order to (at least initially) discourage moss growth.

A dozen maple seed pots with the remaining 3 pine seedlings. Re-using some yogurt pots to free up some finer plant pots, since these could take a very long time to germinate.

I was most happy when I cleared out a couple of the pots that I had stuck monkey-puzzle nuts into, which were over-run with moss and mould, and discovered that the seedling I thought had died when the mouldy seed case snapped off the stalk quite low down, was still very much alive.

Monkey puzzle baby, hanging in there, to be re-potted soon.

I've also now sown about half of the mulberry seeds that have been stratifying in the fridge, to see whether 4 months is long enough for them. Thankfully they didn't get infected with a mould when they were first sealed in there.

From left to right, a cutting of the epicormic side shoot that started growing out of a damson tree (hoping it's rootstock, which would be useful), some sage plants about ready to be re-potted or planted out (some rosemary seeds in the same pot have still failed to germinate), a tray full of mulberry seeds, and the remaining un-germinated arbutus unedo in the back.

Printing PLA on Paper

2012-08-11T17:54:00.000+01:00

A few days ago I started doing tests of 3D-printing PLA using paper as a build surface, since I previously saw it briefly trialled with some success.

My first test mimiced Doxin's test by simply using cheap white A4 printer paper. The first things that I tested printing on the plate were: a new and more robust axle support for my spool stand, and a couple of the ball-joint pole-end-caps for EFFALO's 2V geodesic dome connector set. The paper wasn't clamped down very well since I could only find 4 bulldog clips at the time, and had wrinkled up either end of the paper slightly when attempting to clip it with its longest side in the X-axis before settling on having it along the Y-axis.

Paper set up for first test.

I pre-heated the printbed to something around 90C at full power, and then set it to half-power before starting the print. (I should probably note here my peculiar heated bed setup for anyone who hasn't already seen it; after a kit from mendel-parts that came with two 70W variable-voltage laptop power supplies didn't prove sufficient to print with ABS on its own, I got a simple standalone 12V-fixed supply to dedicate to the gen6 control electronics, while connecting the laptop supplies to the heated bed in series. With them set to put out a total of about 32-26V, and a total of roughly 8Ohms on the printbed heating resistors, I am usually just over their maximum working amperage for 12V, which gives me a temp around 100-110C needed to keep ABS stuck down to the printbed. However, I have no automated feedback control over the temperature during printing since that gen6 board doesn't support it.)

Initially, the adhesion between PLA and the paper surface seemed to be just great, much better than to kapton (polyimide) tape anyway, which has been a good surface to use for ABS.

Laying the first layer down.

However, several layers in, one of those small ball-joint parts started to give way from the paper surface.

Unlucky that adhesion was lost, but lucky to catch this moment on camera as the nozzle kicked one part up on its way past.

I left it alone to see how it turned out, partly to want to do a full test and partly because the part that had broken loose was tiny while my frame part that was most of the print had already committed a fair amount of PLA. You might also see in the picture above that the paper had started to curl up at the edges due to some shrinkage of the PLA as it cooled.

Finished test-print.

I was somewhat lucky that by the end of the print, the other two parts hadn't been destroyed, as strings of PLA being extruded into air next to the displaced part ended up anchoring it in place, hence the neat dome on top of a mess above.
When I allowed the parts to cool, I found them far easier to remove than was suggested by Doxin

First paper test part removed, without any cleaning.

The paper barely seemed to stick to the PLA part at all, and although it had a faint tinge of white, I didn't have to wipe any paper off of this part or the ball-cap that survived. The part was slightly warped once it cooled due to the amount of slack given by the paper, but it is still completely usable for its intended purpose.

For my second test I clipped down a sheet of printing paper again, making sure to keep it as flat and taut as possible with the bulldog clips. Once again I pre-heated the printbed at full power, this time making a note of its temperature as 91C across the paper, while 95C on the kapton surface at the edge, then switched it to half-power when starting a print of two top vertices and two footed vertices from Prusa's 2nd iteration reprap parts.

2nd test 1st layer, notice that for some reason these newer parts have arrows that should point away from gravity when assembled, or in a bunch of directions people have called 'up' ever since uninformed goat-herders declared the earth to be flat.

I took a bit of footage of this test, showing in rubbish phone-quality video how well it got on at the second layer:
By about the 5th/6th layer I started to notice that the paper was increasingly wrinkling up and that at least one of the vertices was starting to peel away from the paper at one end. I quickly measured the bed temperature at about 55C through kapton tape at the edge. My best guess at the time was that having the printbed on at 18V was not keeping it hot enough to keep the PLA sufficiently adhered on the paper surface, due to differential expansion and contraction between the two materials as they cooled, since I had seen the paper wrinkle up a lot when I switched the heated bed off at the end of the last print, before the previous parts came off easily. So, I set the heating back onto full power til the end of the print, went out to do some gardening and hoped that the parts would remain stuck down.

They did.

The part quality was pretty good, but after I switched the bed-heating off and allowed them to cool, I could see the paper wrinkling up a lot as they warped from cooling contraction.

Reverse side of the paper, with parts still attached, gives a nice visualisation of the stress/strain being put on the paper by contraction of the cooling PLA.

The amount of warp wasn't huge, but it was enough that I probably won't sell these parts to anyone, and just use them if I'm building some frame of my own, such as for a base for my rotary-hydroponics unit, since it could be annoying when trying to get a printer frame nice and square. The amount of paper that remained stuck to the parts instead of peeling off cleanly probably covered about 10% of their area, but it was pretty easy to scrub/scrape that off afterwards, although they would be completely usable with a smudge of paper stuck to one side.

Next I wanted to see whether newspaper could be used as a printing surface, since it can be easily procured for free and would be better than wasting higher-quality printing paper. I was wondering though whether the dye on the newspaper might stain the parts, and whether that would make them look ugly.

First newspaper test sheet clipped down. +10 points for recycling and +9000 points for something other than the 2012 olympics on the front page.

Not wanting to risk having trouble with adhesion due to heat changes during printing again, I swapped out the voltage-setting block on one of the power supplies so that I now had 18.5V+12V. After letting this warm up for a while I took quick temp readings of 80C through tape at the plate edge, 75C at the paper edge, and 81C in the middle of the paper, then set a print running to built two Prusa-i2 footed vertices.

The first layer just finished, adhesion looks fine.

By the end of this print those temperatures had just crept up to 93, 90 and 97C respectively, and the newspaper barely curled up at all during the print.

First test parts removed from newspaper print surface.

This print went fine, albeit with as much warp as the previous test, and my suspicions about staining the PLA were confirmed. Scrubbing the excess paper off didn't noticably take any dye with it, so I think it has soaked into the first layer of plastic. I don't intend to sell these either, unless someone out there sees some artistic merit in a pair of footed mendel vertices with part of "inverness highland games" across one side of them.
This gives me ideas about intentional applications of printing on dyed paper though; perhaps some aesthetic or functional designs could be displayed on the outside of parts by printing them to scale with your intended parts-plate and then zeroing the extruder on a set point on the paper. More appealing to any parents out there wanting to print something fun for their kids, it could even be possible to print a PLA jigsaw puzzle this way, with the PLA soaking up dye from a digital image mirrored before printing on a regular inkjet printer.

On to the second test, I set out a plate of 8 bar clamps from the Prusa i2 set, and 4 of the ball-joint caps that I had a problem with before. If anything was going to let go from the paper here, I expected it to be them with their tiny footprint in the first layer relative to their height. Temp readings here went from around 80C at the start up to 85C when I stopped it, due to this:

Several layers in, things got a bit messy.

I was very surprised when most of the bar clamps started coming loose from the paper, and there didn't look to be much hope of this print producing anything other than a mess, so I aborted it to investigate.

Marks left on newspaper by small parts after removal.

All the parts were easy to remove from the paper, taking no paper with them at all, and it seems to me that what happened here was too much ink in the heavily black-dyed sections interfered with the parts adhering to the paper, acting like a thin layer of dust that quickly gave way, which makes sense if the newspaper was produced by laser printing, in which particles of dye are attracted to the paper by a charged roller and sealed on with heat.
I guess this means I won't be getting any bar clamps with a snapshot of someone's kilt on one side, unless I can find someone to supply me with tartan filament (it'll probably be widely available in web-stores by April now that I mention it).
Speaking of which, I recently received a delivery of more PLA filament from a new-ish UK supplier called FilamentPrint, who provide PLA not only at a competitive price in general, but importantly to me with a cheap delivery service who are actually cheaper than Royal Mail when delivering to the Scottish Highlands, which I haven't seen any other couriers do (most of them seem to loathe all the driving up single-track roads to get here and demand a hefty surcharge). One of their new staff apparently managed to misplace one of a few 100m PLA reels that I ordered when packaging it, but when I asked about this by email I got a very apologetic reply 1 hour later from someone else at the firm saying that they would send out the missing spool of filament the same day, when it was already late in the afternoon, and it turned up yesterday. I doubt they'll be making another mistake like that quickly, so I would recommend them to anyone on this island starting out with 3D printing, on the basis of both price and customer service.

Back on topic, I was almost ready to give up on newspaper due to that mess the other day, but I did one last test shown here to see whether distance from the centre of the paper was affecting adhesion strength at all:

A hub part to make one of my modular filament spools.

While surface adhesion for this part was quite solid, it warped quite badly in spite of my finding a few more bulldog clips to place around edges of the paper, and I ended up trying to flatten it a bit by leaving a book on top of it with a couple of full 822g jars on top while the plate was hot. It seems to be a usable part now, but this warp problem is putting me off using paper as a print surface.

For my initial conclusions, so long as there isn't a huge amount of ink present, it seems that adhesion is more reliable than on kapton tape alone, which I can only get PLA to print on after wiping it clean with a dash of dark rum (yes, no joke, that actually works; my theory is that after the ethanol cleans fingerprints away, a thin brown-sugar-derived residue is probably left behind that aids the sugary PLA in remaining stuck down), while using acetone to clean the printbed has only worked before using ABS for me.
There is a bit of a paradox in that larger parts appear to remain stuck down to the paper better, while those same parts are more subject to warp. Paper might prove effective for small parts that are unlikely to warp, wherever the first layer has enough surface area to adhere well. I've also just been thinking that perhaps warping problems might be reduced to some extent by using stiff card instead of paper, so that it can't wrinkle up - using the inside of dry-food packaging boxes as a print surface, before recycling the cardboard, might be a worthwhile experiment.
Of course, a thin plate of glass cut to the size of a reprap's print-bed is still the best surface that I've heard of for PLA, but when the nearest glazier's shop to me is 100 miles away, I can only make do with what I've got for now, and I think that will be trying to keep a kapton-tape surface scrupulously clean from finger-print-grease.

Lessons in Rapid Prototyping and Design

2012-08-04T17:32:00.000+01:00

Never before did I realise what a huge difference software and firmware can make to 3D-print quality.

Not long after setting my reprap up again in its new home, I found it having problems moving in the Z-axis, where the motors would refuse to move half the time, which after describing it on IRC people helped me figure out that the controller was telling the motors to accelerate too fast.
The acceleration that had been implemented in June 2011 Sprinter firmware still caused a significant amount of 'jerkiness' in axis movements. By updating to the latest version for June 2012, not only did more appropriate acceleration, adjusted by a predictive 'look-ahead' buffer, improve this current problem, but it also cut out a vibration problem that broke my Y-axis last year, by pausing at the end of each move for a few ms, when making very short successive movements in order to draw a narrow zig-zag fill line. This helps because in most stepper-motor use there is no feedback control mechanism - the idea being to move a set number of steps then lock in place and hope for the best, which in reality can result in nasty vibrations. By stopping for a moment, the transient vibrations resulting from overshoot can settle, so there is less chance of them feeding into some resonant frequency and shaking the printer to bits.

Illustration of overshoot, via Wikimedia Commons.

In the new firmware a minimum temperature is now set by default, which might have prevented another previous incident that I had with over-heating when a thermistor connection broke.
I also upgraded to the latest version of the Printrun host software along with the latest version of the bundled Slic3r gcode-generating software; aside from pronterface's new easy-to-grasp user interface and slicer's big reduction in complexity over skeinforge, there are a couple of things that I like most about this: a function in slicer that sets a minimum distance the extruder must travel before filament will be retracted (useful where lots of repeated retractions on complex narrow infill used to make my extruder jam, such as with this part), and another one that defines a distance to move up in the Z-axis at the start of every retraction and drop back down at the end (which for a little extra print time can prevent the nozzle from ever dragging through lines already set down, which is important on the first layer while a bond to the print surface is still forming).
In summary, if you ever meet an open-source programmer, give them a hug.

Meanwhile, I recently discovered something that wasn't so well coded in a proprietary program, SolidWorks. When I had tried to open STL files in SolidWorks before, all it did was import 'STL graphics', which was essentially a picture of the object in question that you could rotate as eye-candy but had no solid surfaces that you could sketch on to cut extra holes or extrude extra structures. With lots of other people complaining about the number of things posted on Thingiverse with only STL files supplied, since they couldn't edit them in SCAD or some other programs, I pretty much wrote off the possibility of editing those designs for the last year, figuring that it wasn't an easy thing to do in any CAD software yet (though something at the back of my mind said it should be).
A few weeks ago while looking for SolidWorks-compatible files in order to make some edits that I'd been wanting to make to Greg's Hinged Extruder for months, I stumbled upon some options that allow SW to import STLs as solid bodies, and hence enable them to be carved up any way you want.

Solidworks STL Import - Default Options

Solidworks STL Import Options - how they should be by default.

I was kicking myself for not spotting this before, as this pretty much opens up all STL models on Thingiverse for fixing/editing. Since I'd already started, I continued to create a modified M4 version of that hinged extruder using Tom's SW file, but was now also enabled to edit Greg's 'guidler' part for a better fit.

Meanwhile I found that the old v5 extruder hot-end that I got with my kit from Mendel-Parts was increasingly creating problems for me. I was already annoyed that they stopped supplying replacement parts for it around the same time that the PTFE barrel on mine became warped at its threaded end, and I had been reading that more current hot-end designs using a thin PTFE liner that extended far down the barrel, minimising the contact&melt-zone and hence friction against metal parts, were practically never jamming by comparison, which was making me want to upgrade. For this reason I got hold of a J-Head nozzle from local supplier Reprap3D:

The J-Head Mk.IV-B looks damn sexy by comparison, with the heatsink-notched PEEK body and all-in-one nozzle-heat-block that improves heating efficiency. Shown here after I had applied some Kapton insulating tape.

Not only was the large force required to push plastic through the v5 nozzle a problem, along with the weakness of the PTFE used for its main body and the fit problems and extruder-body damage that came with the PEEK-block mounting system, but the original connections that I used to the heater and thermistor were giving out. The small bootlace-ferrule crimps were giving way one-by-one from months of vibrations, and as I soldered each connection back together, I was having other problems with short-circuits, broken circuits, and eventually, total failure of the thermistor resulting in overheating during printing.
There was a fluke of the kind favoured by cheesy hollywood writers, whereby one of the last things I was printing as the old nozzle failed, was a new extruder block to fit the new hot-end. Due to overheating it was badly warped and I had to cut some holes into better shape with both drill-bits and pen-knife, but here are the old and new extruders for comparison:

Left: Old'n'busted Mendel-Parts v5 in my M4 extruder body. Right: New-hotness J-Head Mk.IV in a prototype M4 body.

The left extruder body was already a temporary replacement for one that was breaking after previous overheating problems. Had the original design incorporated the zip-tie slot shown in use on the right, the ferrule connections might have lasted a bit longer. The new connections themselves I fixed in a different way. Instead of crimping wires twisted up along a straight line with the resistor pins and thermistor wires, I put them end-to-end, twisted the connections together, crimped a ferrule over them, bent that ferrule back on itself (which tears it slightly), melted lead-free solder over the ferrules for reinforcement, then tightened heatshrink around each tough little block. Hopefully this should stand up a lot longer, but I'm keeping the old extruder in a box as an emergency replacement (though I'll be needing a new thermistor for it anyway).
Theoretically it's not advisable to use lead-free solder (mine says it is 96.5% tin, 3% silver, 0.5% copper) so close to a heating block that routinely exceeds 230C when printing with ABS (or could be even higher with PC), since the melting temperature of tin is 232C, but in practice the little distance from the heating block and passing air keeps the temperature slightly lower, so all that heat is likely to do to them is keep the joints from becoming brittle.
Since starting to use the J-Head hot-end I've noticed a big increase in print quality, which may be mostly due to the slightly smaller nozzle diameter - the new one has a 0.4mm outlet while the old one was 0.5mm.

In other news, I've just released a few files with a glimpse of my cowled wind turbine design-in-progress that I've been mulling over for a couple of years now and sketching up ideas for in short bouts of inspiration. My hope is that with something more solid to look at with some very recent CAD work that I did for it, some other designers may be able to help me to improve it.

My 'Storm Turbine' design 0.2, about half the design work done now.

Once I get a moment I'll probably write up a wiki page for this project on Open Source Ecology.
I've also started doing my own tests with printing PLA onto paper, so will report back on that shortly, brb need to eat now.

It Hits The Fan

2012-08-03T01:20:00.000+01:00

Gardening in a region where you're almost always surrounded by sheep has its obvious pitfalls...
Sometimes those sheep or their mischievous little lambs find a way past the fences you put up, because they can see that not only is the grass greener on the other side, but there are also tasty things other than grass to chew on.

One or more of those sheep got over a fence recently and wreaked havoc among the crops I'd planted, trampling some while eating the tops off others...

They seem to love eating fiddleneck flowers

...and of course crapping on all the vegetable beds.

They even chewed most of the leaves off a low-hanging branch of this damson tree, which is more something that I would expect goats to do.

As if the rabbits weren't bad enough.

Back on a windowsill, what initially looked like a blueberry it now seems is not; I don't recognise these flowers:

Do you?

Meanwhile, most of the tree seeds that I have tried to germinate so far, haven't.

I've had no success so far with Strawberry Tree seeds sown after 6 or 10 weeks of cold-stratifying, and only one Scots Pine seemed to germinate weakly after 6 weeks.

I'm not sure why it got thin at the base like that, but it may have something to do with hibernation times, or could just be a dodgy seed.

Scots Pine seeds seem to have been the most successful so far, germinating about 50% of the time, though half of those become weak and fall over (or get knocked over by pets):

These were sown after 10 weeks.

The one Monkey Puzzle seed that germinated, out of four that I planted a few months back, eventually succumbed to a fungal infection and snapped off the stalk. I'm thinking that maybe I need a lighter potting soil to sow some of the seeds in than the garden-variety compost that I've been using.
Also, since all four Elaeagnus cuttings that I tried to propagate indoors appear to have slowly died, I think I'll make up a rooting mix from brewed willow next time I try and do that, in case that can help them to establish. Forgetting to clip their remaining leaves in half can't have helped either.

Confluence of Aspirations

2012-06-23T01:47:00.000+01:00

On locally appropriate crops, some Alpine Strawberries that I planted out along the swale wall from pots are doing fine, and I hope to give them some rhubarb in between for company soon by separating some of the rhubarb that's already growing around here.

This Alpine Strawberry plant is just going through flowers and starting to grow fruit at the same time.

Speaking of which, a single patch of rhubarb in a garden here made a bumper crop this year, producing about 6kg of usable stalk (leaves were composted), which with a handful of cooking apples made enough jars of jam to last a small family a whole year.

I told you those leaves could get big.

I've only managed to germinate two tree seeds so far:

The monkey puzzle seed that previously had me concerned with spots of mould was the first one to shoot up, gradually pushing the seed out of the soil over the course of about a week. This photo was taken nearly a month ago, after ~5 weeks in the soil, and since then it's fallen on its side and barely grown a few millimetres.

This Scots Pine seedling is planted in a re-used Yakult pot, see where I cut the tiny bottle such that the top half would fit in the bottom half, which acts as a drip-tray (it helps to puncture the side above where water will sit, so that air pressure doesn't stop water draining through to the bottom).

In the background were some trays that I'm trying to grow more perennial herbs in, such as rosemary and sage (which are supposed to make good companions) and lemongrass. Most of the nasturtiums that I planted straight outside earlier in the year haven't germinated, and those that have are tiny, so I'm trying to see whether I can get any of those to germinate in pots inside now too.

Here the rhubarb, asparagus and blueberry that I kept inside are doing very well though, after all growing from seed.

Divided asparagus and rhubarb growing strongly.

The only highbush blueberry that I germinated from what I sowed, growing in its own pot. At least I hope it is; the stem should become a bit woodier if it really is blueberry.

Frustratingly I haven't managed to get chives or onions to germinate much so far either outdoors or indoors. I don't think they like it here.

The 'fiddleneck' green manure that I sprinkled in many places seems to be the most successful plant here though, so I guess the soil quality is quite poor, and hopefully this will improve things. Here you can see one in flower.

Meanwhile, I've only just set up my reprap again, after having trouble going through ridiculous numbers of boxes trying to find the right bolts to put a desk back together to support it on. Hopefully now I'll be able to get back to sending reprap parts to other makers, prototyping my rotary hydroponics rig, and working on a safe small wind-turbine over the next few months.

After travelling a few hundred miles, getting everything connected back up, adjusting the Z-axis height and prodding the bad connections on the extruder hot-end to get it to heat up, it quickly knocked out an upgrade part I designed for the x-carriage, with just one false start on the bottom layer. I'll have to replace that hot-end with something better soon.

It was good to get back to chatting with reprap developers on the freenode IRC though, and something very interesting turned up today. A new user going by the name Doxin came on asking about calibration and PLA-use, and then asked a question that was a bit outside the current box, whether printer paper could be used as a 3D-printing surface instead of tape or glass. I know masking tape has been used a lot for PLA prints, so figured it might work and encouraged them to try (though suggesting a fire extinguisher be handy :). The results were very pleasing to see.

A test print stuck down just fine to paper held on by clothes pegs. I'm told that with the ultimaker that this was printed on, the bed remains stationary and extruder moves in 2 axes; stronger clips would probably be needed with a moving printbed as on a reprap or makerbot.

While the plastic stuck so well it tore up some paper, this was apparently very easy to scrub off with a fingernail and damp cloth.

That maker reckons this is far more convenient than using tape. If large sets are printed on a single sheet, I reckon it could even be better for the environment, especially if some scrap like newspaper is used. I'll probably try it out myself next time I'm printing with PLA. The related photo album is here.

In more salvage efforts, I got this heavy-duty motor from an old and busted washing machine:


Such a high-powered motor, if I can build a controller for it, could be very useful for a DIY industrial machine such as a lathe. There are no stickers making it obvious, but I think this thing might run off high-voltage AC from the mains.

It appears to be an induction motor though, so wouldn't be any use for generating electricity. There are strange wires around the back end here and a chunky connector with 7 flat pins just off the bottom of this photo.

There's also some odd wire-pulled lever next to the shaft that looks like it might be a brake, but I haven't figured it out yet, and might just get rid of it.

Flora and Fauna Identification in Sutherland

2012-06-01T01:36:00.000+01:00

In this post I will try to identify many of the seedlings and volunteers/'weeds' that I have seen growing well around my local area in the cool maritime climate of Sutherland, around the North/West coast of Scotland. Your help is greatly desired, so please leave a comment if you have a clue! This post will be updated until I consider it reasonably complete. (Last updated 1/7/12)

As for local flora, daisies, dandelions, nettles and heather (all with edible parts) are so ubiquitous around grassy areas here that there's no point wasting a photograph on them. Seriously, this last month I've seen a whole sheep field turn white with daisies, mowed lawns shine bright yellow with dandelions, everyone on this island has probably seen how nettles like to take over any odd nook or slope where moisture gathers, and heather... well let me just say that every few years the sheep farmers set entire hillsides ablaze up here to get rid of the stuff after it has taken over; some of the current google maps satellite images for the region still show glowing patches and smoke clouds at low levels of detail.

Most plants here suffer salt-burn from the coastal winds if not well protected, especially trees:

This is a native Rowan tree, known for producing a quite tart fruit similar to cranberries only much more sour, typically used to make jellies to accompany meat, otherwise a great bird food when left on the tree. It probably prefers to be further inland though.

I saw these beautiful flowers by the roadside, and I think they are a relative of thistles and artichokes, given the shape of their flower buds.

I have identified this as Common Hogweed, which is edible, and I have tried some myself. The youngest shoots are supposed to be the best, as with many plants, while older bits of stalk etc. are mostly just good for soups. However this plant also has a huge and highly irritant cousin native to the Caucasus, known here as Giant Hogweed, and you should watch out for that plant invading here.

I have seen several of these growing healthily near here completely untended, but the greatest concentration I have seen of them was at a council dump-site, so I suspect that they might lock up some toxins in the soil, and would bet it's not a good idea to eat them.

This nearby tree looks similar to a siberian pea tree, but I think its leaves look too big, widely spaced and waxy to be one, and that it was probably introduced from outside this region.

This picture taken nearly two months ago is of a hedge that was doing quite well facing towards the sea, clearly making a great hardy windbreak. I wouldn't mind knowing what it is.

The spiky little shoots dead-centre of this picture have started springing up on the large sods that I turned over where trees were planted.

A lot of these plants with their three-sided pinched leaves and yellow flowers seem to turn up just off the banks of streams around here.

A young bush on the bank of a stream, could be an edible berry or something like that.

I suspect that this Arctic Poppy may have been introduced as someone's ornamental plant, and has since begun to spread like wildfire over grass verges by roads and footpaths. I didn't notice any sign of this perennial until these big flower buds started appearing and opening in May. Sadly it doesn't appear to be very useful.

Not very many of these turn up amongst the grass. No clue.

The plants in the foreground with their tightly-bunched, slender, green ovate leaves, which start out with a slight purple tinge (as with the bottom-right shoot), I originally thought might be one of the green manure plants that I sowed a couple of months ago, when it first started springing up, since it seemed to be everywhere. Since noticing it often amongst the grass I have been told it is a type of Vetch, although I don't know which yet, and there are nearly 30 species of it listed on PFAF. At least I know it is a legume, so will probably be improving the soil of the swale mound, which it is growing out of a lot.

What I originally thought might be related to clover due to its bunched flowers, is actually an orchid.

This mystery turned out to be a volunteer potato, probably from a seed or bit of root that got into the compost I spread here.

This other mystery popped up inches from that previous one, where I found part of my compost scraped away a couple of weeks ago, possibly disturbed by a mouse or rabbit.

I think this could be carrot seedlings in the middle of the picture.

The largest plants here from seed, which are growing strongly everywhere I sow them, I am now sure are not carrots but in fact the 'green manure' fiddleneck. I wish I could get something edible to grow that well.

Bonus question: is it just me, or does it look like that shoot at the grafting point of this damson tree could be from the rootstock? If so, perhaps I could be able to propagate it in a pot and use it to grow more tough plum/prune trees. Also, that's the shoot of a garlic clove that I planted slowly creeping up to the bottom-left of the tree.

As for fauna... while we have had some very hot and dry weather (for here at least) with no rain for the last week, I tried going out late at night with a watering can to help my recently-sown seeds and seedlings, since the constant sunlight during the day was drying out the compost to the point that it was cracking up. On my way round I started spotting slugs attacking various seedlings. They came in all different sizes and colours, some brown, cream, white, green, yellow and some even speckled with black spots. I didn't find any with distinct orange bellies, which I have come across lots of before towards the south end of this island.
This seems to be a negative side-effect of putting solid objects down to mulch areas overgrown with grass, since the moist sheltered area underneath is a great place for slugs to breed.

This one was chowing down on one of the seedlings from the peas I planted along my swale wall. That annoyed me.

After the satisfaction of hurling a few of them far over a fence wore off as I kept noticing more and more of them, realising what a huge plague of these slimy little buggers come out at night, I guessed that they may have been a main reason why a lot of the things I sowed straight outside and then left for a few weeks seemed to be missing in action, and that I'd need to do something quick if I wanted many of the things that I had more recently sown to survive.
Its said that you can't have too many slugs, only too few ducks, and I had wanted to borrow my friend's ducks to range them around the planted area in late spring, but unfortunately they were all wiped out recently by some fox or badger that managed to claw its way into their decrepit old shelters and start surplus killing, so now there are no ducks or chickens left in the whole village and I haven't had enough time to build new hutches to protect more ducklings. Therefore I have had to look at quick solutions to my slug problem other than domesticated animals.

The first idea that sprung to my mind was to try and get hold of some plain terracotta clay and compact it down in the wide section of the swale I dug, so that it might hold water and form a pond, which in turn could attract some of the wild ducks that fly around this region. I put that off for now on account of the time and effort involved, since I would likely have to try and establish some aquatic plants that are attractive to ducks while my own seedlings are getting munched.
The next thing I came across online was a beer trap, a.k.a. 'slug pub' or 'slug inn'. This is where you leave out an open dish with some beer poured into it, the idea being that slugs love their beer for some reason, while they are quite incapable of processing the alcohol, and so get so intoxicated that they fall into the drink and drown blissfully. I could come up with a hundred euphemisms for that, but moving on, I had doubts about the trick until two family members assured me that it's a good one, so I tried it the next night.

Results of a dish and one can of crap lager after 24 hours.

I was quite happy with the results, and the usual wisdom that I read was to toss out the contents out and refresh the tray each day, but I decided to try and see whether it would still attract many slugs the next night while going a bit stale. I also tried putting some lager in steep-sided mugs to see if that would make slugs fall in more easily, but my success seemed to depend more on how sheltered a location a given trap was in. The wide dish pictured was in a narrow part of the swale, while a mug near the top of the hill caught nothing and one in thick grass near the south-west fence was almost as successful as the dish.

Slug pub after 48 hours.

From counting slugs by naked eye, I estimate the trap to be at least 50% effective in distracting slugs within a radius of maybe 5-15 feet, but I still found a few on important seedlings like my artichokes and this rhubarb:

Though I dropped this slug in the drink, the rhubarb seedlings that I stuck outside were all eaten down to stumps overnight, evoking much of my wrath. At least the ones I kept inside are doing very well though.

and finally:

Slug pub after 36 hours. Muahahahaha.

Those dead slugs are now on a compost heap since none of the birds around here seem to have noticed the feast sitting there. I guess the woodland system will have to become a lot more developed before it gets regular bird visits.

Sowing Perennials Indoors

2012-05-20T02:16:00.000+01:00

Progress was slow over the last few weeks; I lost a lot of work time looking after a friend's hungry hair-generating quadruped for them while they were away (I'm getting a bit tired of the number of animals people feed with agricultural produce when this society won't even distribute it to all humans, can you tell?), but I have learned some more about what works in this region in the meantime.

Most of the fruit trees have started blooming, this damson tree was the earliest.

I got hold of some tree seeds to see if I can grow Siberian Pea Tree as a productive tree-legume, and a few other useful trees and shrubs such as Sugar Maple, Scots Pine, Strawberry Tree, Black Mulberry, Broom, Oleaster and most importantly, Monkey Puzzle. Monkey-Puzzle trees are a lifelong investment as they produce prolific amounts of large nuts in a temperate climate, but only after about 30-40 years of growth from seed, although Ken Fern of PFAF has reported some of his trees in Cornwall producing cones around 20 years old. A few of the large monkey-puzzle nuts each got their own pots after nearly two days of soaking in water.

Pre-soaking tree seeds to cold-stratify.

Most of those seeds need to be cold-stratified to simulate over-wintering before they will germinate in what the seed thinks is springtime, so I soaked a bunch of each in water for just over a day in small jars, then drained the water out, labelled them for their recommended chilling times and put them at the back of a refrigerator. For some of the couple of leguminous seeds, pea tree and broom, which should be able to germinate without chilling, I spotted a fererro-rocher tray from a previous winter's gift that made an excellent propagator tray for germinating the seeds in. With a teaspoonful of wet potting mix in each slot, after piercing the inner tray for drainage, I planted a dozen pea-tree seeds, three broom seeds and a few of the others that looked like they might germinate easily just after their soak, then covered the tray over.

That's not chocolate in that pretentious yet thankfully re-usable acrylic packaging.

One month after putting those seeds in soil, none of them have yet germinated, and a couple of the prized monkey-puzzle seeds appeared to have flecks of mould growing on the upper sides of them every time that I watered them in the last couple of weeks, which makes me worry whether they will germinate at all. I've scraped it off each time it appears, but it keeps coming back whenever there is some moisture in the pot.

Fluffy white (and in some places, green) mould growing around damp monkey-puzzle seeds. Is this a penicillum mould? Any tips would be appreciated.

There are several perennial herbs that I want to try and grow in some of the sunniest spots on the hillside, most of which are usually more suited to a mediterranean climate. I want them both for delicious food and because they make great companions for nightshade plants, some of which (tomato, aubergine) are already very difficult to grow in the local climate without pest infestations. I sowed seeds for a few herbs (oregano, marjoram, rosemary, thyme, along with chamomile, fennel and a couple of artichoke and squash seeds) in an old seedling tray I found, and kept them indoors for a few weeks so that they could germinate in some shelter while there was still a bit of frost, which those herbs can be sentitive to when young, while giving me time to prepare a patch for them to grow on.
The rosemary seems to have been the most stubborn to germinate out of the whole bunch, showing no sign of greenery after a full month (although I wonder whether the peaty potting mix I sowed them on was too acidic), while the chamomile seemed to spring up within a couple of days and the rest of the herbs did ok within a couple of weeks.

Seedling identification: Counting left-to-right from the top row (starting at blue marker) down, I sowed Rosemary in 1, 2 and 19, Oregano in 7 and 13, Thyme in 8, 14 and 20, 'Cinnamon' Basil in 3, 9, 15 and 21, Globe Artichoke in 4 and 24, Chamomile in 10 and 16, Luffa Gourds in 5 and 6, Spaghetti Squash in 11 and 12, Marjoram in 22 and 23, and Fennel in 17 and 18. All were sown at the same time and pictured here after 2 weeks.

At the same time I dedicated some old margarine tubs to germinating seeds of a couple of my favourite edible temperate perennial shrubs, asparagus and rhubarb.

Rhubarb seedlings, 2 weeks from sowing. A three-leaved mutant seedling on the right of this picture didn't survive.

I have seen rhubarb growing very well in large clumps here in all sorts of locations, from full-sun exposure on a south facing hill, to shaded spots around the side of buildings and even growing between a couple of rocks on a roadside.

A healthy old local rhubarb patch, those leaves can get huge, as in 2-3 feet long not counting the stalk, so that you could fan yourself or a loved one with it on a hot day.

Rhubarb makes a lovely spring/summer pie or jam, but asparagus, which can put lots of nutrition in some lovely savoury dishes, I have yet to spot growing anywhere nearby. The asparagus seeds that I potted took a few weeks to germinate, but then all sprung up at roughly the same time, making a nice surprise. The first thing to germinate in one of the pots was a mystery weed, which left me confused until the tiny asparagus heads appeared a few days later and I now think it might be a thistle, but I didn't pull it up since an asparagus shoot growing directly next to it ended up doing very well, so I guess it isn't doing much harm.

One of two asparagus trays, 25 days after sowing.

To save a bit more time in creating vegetable and herb beds between the windbreak, and since I ran out of spare stuff to cover the ground with, I'm doing a little of something that I really want to minimise, which is tilling the topsoil. I've found that my attempt to smother some of the grass by a month of covering it with various opaque sheets followed by spreading compost on the top, has been a semi-success/failure depending on how you look at it.

Grass and other well-established weeds busting through a thin layer of mulch.

The grass is shooting up through the compost in a few locations, and one particularly lively clump simply lifted the compost on it right up after a few weeks of regrowth. Initially I thought this was a bigger problem than it actually is, since I mistook some of the chives and onions growing there for tufts of grass, until I plucked one up; it seems I missed the initial seedling stage that I mainly found pictures of online, where the black seed shells have been pushed above the surface. Disregard that, I just thoroughly inspected the area and practically all of them really are very slender grass shoots, so my onion and chive seeds don't seem to have germinated for unknown reasons, though the packet instructions said they could be sown straight outdoors.
There are some other seedlings growing in the compost that I laid down, but their progress is slow, the 'green manure' plants haven't established much at all in the way of ground cover, and some of the things I sowed straight outside quite early, such as broccoli and artichokes, don't even appear to have germinated, although there are still a few seedlings or possible weeds that I haven't been able to identify, I'm thinking of dedicating a blog post to them since there are so many. I'm quite worried that the nasturtium seeds I planted out early in the year might have rotted before they could germinate, so I might have to plant some more.

~~Carrot~~ fiddleneck seedling in the centre having already developed a couple of branches (updated). I think these probably do really well because they're unpalatable - see my next post for more about the slug problem.

When a nearby ash tree needed to have a branch cut back that was getting in the way, I was able to take several cuttings that might root into new trees, so I used those to extend the treeline for windbreak around the north-east a bit, since some quite strong and very cold winds had been coming in unblocked from north europe/asia in previous weeks. Hopefully this layout can approach an ideal model that Mollison recommended for a temperate-zone windbreak in his permaculture designer's manual, which is roughly a horseshoe shape, where the thick bend of the horseshoe faces the nearest pole.

Here I put some of the cuttings into rows of holes made with a garden fork. Almost none of the buds had opened on the branch that I took cuttings from, while they had across most of the rest of the tree, so clearly it didn't need the extra bit that just made it more susceptible to wind.

The areas where I wanted to lay out some more vegetable patches had too much rock at a shallow level for me to invert cubes of sod with a spade, not that I wanted to break up and expose soil at that depth anyway; ploughing soil up a foot deep often leaves a lot of earthworms out as a smörgåsbord for the birds (as I saw a couple of years ago in the documentary A Farm for the Future by Rebecca Hosking), which doesn't exactly help with soil fertility in the following years.
To try and suppress the grass roots even faster here without ruining the soil too much, I first raked away as much of the dead grass as possible, which from the patch I started making around the plum tree was enough to loosely half-fill a compost bin that I had recently re-assembled after moving it from a previous home (that went to the top of the hill in the hope that nutrients would flow downhill from its base). Next I would try and push a garden fork as close to horizontal as possible under a patch of moss and grass roots, but trying to keep high up on top of the mud and rocks, before levering the fork up and flipping over the shallow sods that resulted.

Example of the thickness of a sod in my improvised 'rake and flip' method, which only requires you and a garden fork. See how rocky the soil is there without going an inch past the main root mass.

Some of the grass roots that I pulled up by hand were amazingly thick, showing the age of this well-established grass that was drawing up nutrients from deep into the rocks.

This grass root was so thick that I would forgive anyone for mistaking it for a parsnip, which is even what it smelled like when torn apart.

After emptying a few small compost heaps from around my friend's house, I put the partially decomposed food peelings etc. into the large reconstructed compost bin with the grass-hay, then spreading the small amount of good quality compost from the bottom over the turned patch of soil. The whole process from raking to spreading compost took a few hours of work to produce a patch about 10ft long by 4ft wide; a lot more toil than mulching the grass but a lot less waiting.

A long flipped-grass vegetable bed leading up to the plum tree, almost finished.

Near-disaster struck when my friend's pet knocked my tray of various seedlings off a window-sill, the very same day that I wanted to plant some of them out after waiting a month for some of them to establish, and I managed to rescue most of them, though I don't know how many will survive once they are planted outside. A couple of the rhubarb trays were merely knocked on their sides, and the soil was quite glued together at the time, so they kept growing fine, though one or two had injuries to leaves that were hanging over the tray edge.
I stuck the artichokes out at the windward (WSW, front of picture) end of the large patch above as soon as it was ready, with some bird seed directly behind for tall grain plants like sunflower, chamomile around the edge since it can grow amongst grass like daisy, cauliflower and cabbage (hopefully sheltered) in the middle, followed by rows of squashes, lettuce, radishes and turnips towards the plum tree, with a few chives directly around it.

One of the artichoke seedlings, just left of centre, with a bunch of chamomile to the top-right.

Further around on the south face of the hill I made a much smaller patch by the same method, sticking out the various herbs around the south edge along with some more seeds of the same generally all over the patch as companions for some tomatoes in the middle, with beans and squashes behind them that I intend to grow up some sticks like a trellis, if they will actually grow.

Tasty herbs, whether they can survive here only time will tell; I have seen oregano doing reasonably well in a raised-bed near here though.

I divided up a tray of asparagus and planted it in two blocks by the west end of the patch backed by some more sunflowers and stuck a few marigold seeds around the edge as general companions for the rest.

Half of an Asparagus seedling tray stuck out along with mystery weed. Maybe I should have thinned them out further, but any that survive shall inherit the earth.

Since rhubarb seemed to do so well in slightly raised mounds that it could spread its large leaves out over, I figured it would make a great element to place on the large back wall at the widest part of the water-harvesting swale that I dug out, since its shelter might lower evaporation of any collected water when the sun is lower in spring & autumn, so that's where I stuck a tray of seedlings out.

Several rhubarb seedlings from the larger tray planted out on the swale/pond wall. Some more peas were planted behind and anywhere else that I hadn't put any on the wall yet.

While doing some backround reading I re-discovered, having forgotten, that fennel, much like walnut, is quite toxic to almost all plants around it, save perhaps dill (which I don't like very much anyway), so I stuck seedlings of that in one small bit of turned soil right next to the compost bin, on the slim chance that it might discourage plants from growing in the heap, and because by a compost bin should be a fine position for any plant, since it supplies all different nutrients to the roots while attracting a variety of insects.

Barely visible are 3 fennel seedlings from left to right across the middle of this picture. I might chuck some more seeds straight on the patch to see if they take, I'm not terribly worried about this plant.

Tragically, the very next day after finishing that batch of working the soil and sowing seeds in sunny weather, an unexpected storm blew through that brought very harsh westerly winds for most of last weekend. While all the trees survived with minimal damage having rooted well now, most of the seedlings that I had just planted out were devastated.

The skies fell, rivers ran with blood... well, not quite, but there was enough rainfall in less than 24 hours to half-fill the swale that I dug, from really not a huge area to run-off from. Taking this picture in what I thought would be a decent lull in the weather resulted in me getting soaked when the rain came back.

The rhubarb was hit quite hard since the wind would have accellerated slightly over the swale wall with no plant life there yet to slow it.

The asparagus seedlings had their top third simply snapped right over.

This post could almost be re-named "How to do gardening wrong by experimentation and learn from it", but I've already learned in tactics to always keep something in reserve, while I realise that I have a better chance of something succeeding well if I try a little bit of everything, as goes the creative process. To that end I only planted out half of the rhubarb and asparagus seedlings that I grew, the other half I will try to very carefully split out into individual pots, to see if I can grow several single strong plants of each to then plant outside.

Reserve asparagus and rhubarb seedlings; if I can grow several strong plants from them, then I might even be able to give a few to friends.

It wasn't until after planting out blackberry bramble cuttings earlier in the year that I read that the opposite to what I found with willow tree cuttings was true, that thicker chunks of bramble cane are better for vegetative propagation, and so on examining the ones that I stuck out, I found only this one alive and well.

This spiky stick of awesome might one day grow into a hedge covered with delicious fruit.

Also, with blueberry seedlings that similar online instructions said should be quite easy to germinate once they have been cold-stratified for a few weeks, I could only get one to germinate here by surface-sowing stratified seeds onto ericaceous potting mix.

At first I wasn't sure if this was a weed or not, since it looked like others I had seen before and it doesn't help when a cannabis breeder names their unique strain 'blueberry', which then ends up being most of what shows up when I search for images online with the terms 'blueberry seedling'. I'm sure that cannabis strain is probably delicious, but could people please stop naming one curious plant after another? We have enough confusion with that already, what with 'strawberry trees', 'cinnamon basil', 'chocolate mint', etc. Rant aside, that's a grass shoot in the background, which was swiftly destroyed once I realised that.

Did you say shrubberies?

2012-04-08T12:08:00.001+01:00

As I mentioned a few days ago, the elaeagnus pungens shrub that I planted from a pot looked quite unhealthy, since most of its leaves were turning pale and some dropping off though it should be an evergreen plant. The hybrid Elaeagnus x Ebbingei from a pot was doing very well by comparison:

Although a few of the leaves were turning that same way.

Elaeagnus Pungens Maculata, after covering the grass around it.

Seeing the other plant in this state was a bit disheartening since it is one of my favourite plants there at least from its reported qualities, although I am glad that I took a few cuttings of each elaeagnus shrub, as all those still seem to be healthy at least by leaf colour, although they haven't grown any noticable shoots in their windowsill location. I'm not sure what caused this shrub to suffer so much, but I have a few things in mind. The first thing proposed by a neighbour was that perhaps the strong coastal wind was too much for this plant, although I have doubts about that since plants from the whole genus are supposed to make a very strong hedge near coasts, and the shrub is very close to ground-level where the wind is cut down heavily by the boundary layer effect.

I was mildly suspicious about a bunch of caterpillars that I saw in a group several feet away by the fenceline; they most likely had recently crawled out from their little silk tents somewhere nearby, but at the size of them I was worried that they might have already chewed up the leaves of the shrub a bit, though I put that down as unlikely since only a couple looked at all mis-shapen or bitten. I first saw one of them on some grass near the swale back in March, and although it was the largest insect around at the time I didn't think much of it, just taking this picture of it so that I could identify it.

From this page it looks as if it's either a Fox Moth or a Browntail.

Next I thought that maybe this particular shrub hadn't done well because it got a bit less water than the other, being more on top of the hill and on the high-side of the swale, while it was larger and so perhaps thirstier, but with the frequency that it rains around here I guess that is also unlikely. Nevertheless I watered it a lot just in case water was a factor.
I later found and read a more detailed page about the shrub on PFAF, 'Elaeagnus x Ebbingei, A Plant for all Reasons', where it said that "The plant is very tolerant of site conditions, the only situation that is a definite no-no is one that becomes waterlogged. It far prefers a well-drained soil, is capable of growing in very poor soils and, once established, is very drought resistant and will succeed in quite dry soils." So I hope that I didn't make a situation worse by giving the plant some more water. I really ought to do a soil test, which I still haven't got around to yet, only knowing that it consists of a few-inches smear of mud over quite a lot of rocks, supporting mostly grass and very little Heather (which prefers acidic soil), but not knowing the clay/sand/peat fraction.

Lastly, I wondered about root shock; upon examining every one of the trees planted, it seemed that they had all spread at least a couple of their buds into small leaves, with the exception of the Ash, Plum tree and the largest Willow cutting that I had taken, the latter two of which also happened to be the trees worst hit by the storm winds that came during the first time I was away since they were planted. I think that injury/damage to the plant roots might have something to do with the weakness of all these plants, however that doesn't explain why the elaeagnus cuttings that I planted straight outside were nowhere near as healthy as the ones inside (but water, soil quality and competition with nearby grass could explain that), the ash might just open its leaf buds quite late though.

A couple of cuttings indoors.

One of the two cuttings outside; they are both in similar shape.

Of course another possibility that I really hope isn't the case, since there would be little I can do about it, is that the shrub could have caught a disease here. If that were true, then it might spread in the soil and could even prevent me from successfully planting any of them in that area for years to come, and they might have to be kept only as pot-plants.
I can still give native shrubs like Gorse and Broom a try as inter-planted perennial legumes to support the fruit trees, although they wouldn't be anywhere near as useful as elaeagnus x ebbingei with its food crop. I may still be able to get a deciduous fall-fruiting Elaeagnus species, Angustifolia (Oleaster / Russian Olive), to grow here, and I'm interested in whether I can get Siberian Pea Tree to grow here.

Besides that, I've been slowly working my way around the patches that I intend to turn into a series of keyhole beds separating walkways, laying down what bits of cardboard, sacks, old tyres and rocks I have on hand to mulch down the soil for few weeks, before spreading some of the little home-made compost and rotted manure I have access to, on top of the then dead or dying grass, to plant seeds in.

Using the leftover pegs from plotting out a contour to mark out where keyhole plant-beds will be, then mulching some of those spots down.

The grass roots are quite stubborn and will try to re-grow through the compost if a gap is left for light (maybe there's a philosophical lesson in that), but I have scattered seeds of some so-called 'green manure' nitrogen-fixing ground-cover plants like Fiddleneck and Crimson Clover, to stop weeds from getting through.

Some of the first seeds I sowed back at the start of March are only just beginning to germinate.

I've heard that people round here usually go with leaving rolls of old carpet across strips of grass that they want to grow some crops on, for several months before taking them off to plant annual crops in the ground where the grass has completely mulched down. I just hope that my accelerated method with compost on top will still allow plant roots to establish into the space where the grass is breaking down. I doubt that carrots or parsnips would ever be able to grow to a good quality in soil of this depth anyway, but I'm still going to try in the softer spots where I can get a pitchfork deeper in before hitting rocks.

Filling the slots in the swale mound built from chunks of heavy soil.

One of the things I just tried in the last day was to patch in the slots between some of the blocks of sod that I turned over for my swale using a loosely forked compost/manure mix to make mini-seed-beds, and planted peas 'n' carrots (apparently they go well together) on top of most of those patches, hoping that the softer groove would give the roots an easy run, making for better carrots and hopefully rejuvenating some of the soil where the peas are.

The Rowan tree opening spring leaves.

Currently the Rowan tree and the Katy Apple appear to be the healthiest trees, or at least have grown the most/earliest leaves, but time will tell which trees are strongest when they all present a bigger area for the wind to drag on. None of the brambles that I planted directly into the ground look very alive, but I don't know what's going on at the root level. On the beds of mulched ground I'm trying to roughly use the set of crop guilds that I sketched up here from mixed free online sources, and will be sure to report on what is growing well where.

A Brief Update

2012-04-03T15:52:00.000+01:00

I hate moving house.

Some of the elaeagnus shrubs are struggling here.

Snow in April.

That is all.

Supporting Trees

2012-03-07T03:47:00.001Z

Recently I noticed a quite old mini-documentary on forest gardening that I thought I had seen before, but hadn't as it turns out, having just seen a separate interview with one old fellow in it, the late Robert Hart, who started a quite famous forest garden halfway down England in Shropshire. This documentary was made up of a series of 3 interviews, which it turns out contain some great gems of knowledge on forest gardening in a temperate climate; the first being with Robert Hart about his 500m^2 labour of love, the second was with Ken Fern, who started and continues to maintain Plants For A Future, a project in Cornwall that has trialled thousands of different plants for their suitability in temperate climates, creating a database with detailed information and ratings based on things like hardiness, edibility, potential poisons, and other uses (you can tell this was filmed in the 90's when he mentions how 'big' a disk you needed to store the database). The last was on the subject of some applied urban permaculture with Mike & Julia Guerra.

I had used PFAF's website before when first reading about permaculture a year or two ago, when there were a collection of very handy general info pages, for instance on why we should be tending to use perennial plants, and some information on the forest layering system on a helpful page about forest gardening. There were some links to useful perennial food crops such as chestnut, walnut, brambles, et cetera, but otherwise the information wasn't very easy to navigate.
I noticed a while back when I looked it up again that the site was down for maintenance, and now that it is back up again, it's quite an amazing change. You should really go check it out sometime (if I didn't already make that clear :), and I think they could do with some support too, since it looks like they forked out a bit to have some people with a lot of talent fix their website up. Now there's a very effective database search function on the site that can let you search by any combination of your needs, such as plant uses, environmental conditions, or simply keywords.
For example, one of the plants that Ken showcased in the aforementioned video was a member of the genus Elaeagnus, sometimes called Oleaster, which had some amazing properties I was looking for all in one plant, and some I wasn't even looking for. It's a nitrogen-fixing perennial shrub that resists a cold windy maritime climate well, so I could plant it up north between our trees to support their growth, just as Acacia is recommended in warmer climes. Not only does it grow quite fast, a great novelty feature of the species that it seems Ken had there, Elaeagnus Pungens, is that it produces an edible fruit in springtime, usually around April, of which both the outer flesh and the oily seed (once hulled) make very useful foods.

I managed to get hold of a couple of such species, and as Ken said, if you can tell me any other fruit that you can get out of your garden in April, I'd like to know about it.

So while that's a great find, I really wanted to know what native shrub or tree species could be used as nitrogen-fixing legumes to support the regrowth of forests in harsh cold-temperate climates, so I popped a simple search into that new database interface, looking for perennials, trees, shrubs; nitrogen-fixing, wind-resistant and maritime-exposure tolerant in hardiness zones 4-7, and ended up with a short list on one page that included a few things I recognised. Notable natives included Broom, a prolifically-growing weed that I've noticed growing wild while in fruit in Perthshire about a year and a half ago, which I could identify through Wikipedia back then when wanting to know if its pea pods were edible (they aren't), and another plant, which is a very common sight in Scotland, Gorse.
Now while I know that Gorse can grow a very strong windbreak hedge, and those who have tried it tell me that you can make a very tasty wine from its flowers, I am reluctant to plant any, both for its ability to grow out of control, and due to a grudge formed against the plant during section and platoon attack exercises over the countryside a few years ago, when I learned exactly how nice it is to wade through the stuff. If I can find another place that someone will allow me to start replanting trees, I may use it as a support species and a hedge to keep winds and sheep out then, but won't be letting it take over some common food-growing ground any time soon.
On a related note, George Monbiot recently posted a very good article to the Permaculture Research Institute, on the problem of land mismanagement and deforestation that has been occuring in Scotland under careless wealthy landlords since the time of the Highland Clearances. It's my hope that we can get enough support in Scotland to start replanting the Caledonian Forest on a large scale, before any more biodiversity is lost.

As for my efforts to reverse the trend of vanishing boreal forest, I went back up north very briefly at the end of February to check on how the patch was doing and see what I could plant.
The first thing I noticed, which I was expecting to some extent due to some stormy weather in the weeks while I was away, was that several of the trees were leaning away from the prevailing wind. It's a common sight to see the few very sparse trees on the north end of Sutherland doing this as a growth habit when they have been beaten by strong winds over their lifetime, but what's not so nice is when a young newly-planted tree has rotated not in its trunk, but at the roots when it wasn't very well anchored.

The very-leaning one on top-left is the plum.

Not only were the trees not very well anchored in the ground since they were planted bare-root, but since they arrived after I left, my friend managed to put a couple of them in backward to the plan I sketched, which they also lost, so on the windward side of our damson (prune) tree with its very dwarfing rootstock, there's a slightly taller and weaker 'katy' eating apple tree. I guessed it would probably just do more damage to the root zone if I was to try and dig them up again to swap their positions, so I left them that way and hoped for the best, my next task being to give those trees some much-needed support.

It was easy enough to right that plum where it was slightly loose and tread the earth back down for a start.

It seemed that the local potted trees, while taller, suffered a lot less in the winds due to already having some stronger-established roots and a sort of counterweight from the pot soil.

The little Katy eating-apple tree only seemed to be managing because it was propped up slightly by a nearby tyre, which my friend had helpfully used to weigh down the cardboard box that the bare-rooted trees came in, as simple mulch to rot the grass down underneath.

I gave the tyre a gentle boot to set her upright again.

The worst-hit seemed to be one of the Willow cuttings that I took the last time, which I hadn't pruned enough to stop it blowing over.

While this needed to be cut back, the other, smaller branches that I planted did just fine.

Next to the bramble cuttings that I planted, which were doing fairly well, my friend had uncovered a couple of hawthorn bushes that were planted a couple of years ago and had grown quite slowly since then, probably because they were surrounded by grass and constantly wind-beaten.

Bramble cuttings in background near fencepost, Hawthorn in foreground.

Also I found out the hairy-looking cutting I took before was a rose cutting, which is useful as rose bushes provide rosehips that make a half decent jam, so keep an eye out for them in suburbs during autumn; I've even found them in retail-park car-parks before.
Inspired by the antics of Bill Mollison in yet another old permaculture documentary, I shoved a few hazelnuts into the ground between the brambles, to see if I can add yet more variety to this windbreak.

As for stopping the trees that didn't have tyres near them from blowing away, the bottom of the wider section of the mini swale that I dug gave me plenty of rocks to weigh the soil around their roots down with.

Hole from a big'un that I just pulled out.

...and that rock supporting a willow.

Another thing that's obvious in the next pic, which I noticed as soon as I turned up, is that there are no pea shoots growing on the swale, nor peas left to germinate into them, as I was a little hasty in the way I sowed them with limited time on my last visit.

'Howgate Wonder' cooking apple tree with some rock support at the back.

Following on from seeing Lawton and volunteers liberally tossing bacteria-inoculated peas from buckets onto a swale in the water-harvesting doc, I was silly and lazily applied the same method, when I was sowing onto cold rocky soil in pitch black while they had some quite large walls of soft soil to sow onto in autumn, forgetting that there were field mice hiding all around me, who probably had a feast on those peas over the last few weeks, not that I mind much with plenty of peas to spare for now, but it taught me a lesson to cover my seeds properly in future.

After unpacking those Elaeagnus shrubs, I took cuttings from the top of each one the next day, so that I could propagate them a little bit and since being tall isn't a great advantage in these winds.

Spare shrub cuttings, easy drill by now; cut just below a leaf node, clip that leaf off and about half of what's left, including a top leaf, soak in a wee bit of honey (or rooting hormone if you can get it) then stick each in potting soil, or in a propagator tray (essentially overpriced egg packaging) if for small plants. The brambles that I treated this way are doing fine.

Then I took the potted bushes out and planted them, plus a couple of extra cuttings that I didn't put in pots like the brambles, to see if they would take root outside while having potted ones as backups.

My planting method was essentially the same as for trees, sticking them in a hole slightly deeper than the potted soil, only this time I lined the hole bottom with some home-made compost instead of duck manure, then put the sods back in upside down as before, mulching the top with raked grass and rocks.

After sticking the rest of the cuttings down, I re-arranged some of the cardboard mulch and added some cupboard-backing fibreboard that I had previously salvaged from furniture dumped on the streets in Glasgow.

Three or four weeks with cardboard on top didn't completely rot the grass there, but it made a big difference.

The remaining compost I spread over the cardboard, starting to prepare a bed for planting a few things. As light faded I went round every tree and planted a few climbing Nasturtium seeds, which should out-compete the grasses and protect the trees with their creeping nature, while making a tasty salad addition (the seeds also look funnily brain-shaped).

The movement of cardboard for mulch was part of a plan I was forming while making up a new and more accurate sketch for the plot over those couple of days. It now also includes a rough plan to divide the ground up into a series of paths and keyhole beds, so as to maximise the surface area available for planting and harvesting crops, without having to tread over food to reach the middle of a patch, and a site to potentially test a turbine on a crest of the hill is marked.

There may be a small spot of hypocrisy here, as I suspect I might have confused the two Elaeagnus species that I got and planted them the opposite way round to what I wrote in this updated map, not that it matters much.

After reading over information and diagrams on companion planting for a while to get a feel for common relations, I decided a good way to help work out large arrangements for planting lots of different crops could be to draw up a list of small guilds of a few plants that strongly benefited each other, suited to a cold temperate climate, and then try to arrange a mosaic of those small guilds based upon the features of the landscape.

'Rosemary' is a bit hard to read in the middle with the flash; but other pictures had some of the outside diagrams fuzzy, so I might just try and replace this photo with a scan.

When I wanted to plant some vegetable and herb seeds on the last day I was there, I was unlucky that a quite constant 10-20mph breeze picked up for the whole day, plus intermittent gusts, which made sowing seeds a nightmare. I settled for just covering one small patch a couple of square metres in size with compost and some potting mix that had become waterlogged, though with the sun coming out to evaporate whatever was left of the previous day's rain, I worried slightly about that soil eroding in the wind once dry.
For the crop arrangement I stuck a few globe artichoke seeds on the windward end of the patch, a few chives around the eating-apple tree to help that, followed by some onions to repel the pests of a row of carrots and sprouting broccoli beyond that, then a patch of lavender in the hardest-to-reach bit that ought to attract some predatory insects, with some more chives behind to help the rowan tree. Where I expected some of the seeds to need deep roots, I jabbed a set of holes through the half-layer of cardboard with a pitchfork and put loose compost into them before sowing seeds. Afterwards I spread some raked grass over the patch to try and keep the soil down under the sun and wind.

I could only be bothered to stake down my little bottle-shelters on the most windward sowings of carrot and broccoli though, having not prepared a lot of stakes and finding them a bit small.

Around the area and some of the swale I scattered a little bit of clover seed to fix nitrogen in the soil, though I might see about getting some comfrey later.
As a little extra protection against the harsh wind and the nibbling rabbits that have plagued this land since the Romans brought them over, I then staked some spare chicken-wire around a few of the trees, which will also give an added benefit of catching wind-blown debris for mulch, while giving nasturtiums something to climb on.

When I ran out of chicken wire, I just used a bit of old string and piled up some grass cuttings into a mat.

Let me know if I cut out too much detail or rambled on too much, it sure seemed like less work before I tried to write about it!

Replacing Small Parts by Rapid-Prototyping

2012-02-25T22:16:00.000Z

Since getting back to the city I've been on a small spree of trying to find little things that I could replace or redesign using 3D printing, whenever there was a moment to spare.

Firstly, for a long time I'd been meaning to make replacement parts for a very humble purpose, the male buckle clips on a couple of Highlander rucksacks I have that had mostly lost their teeth after many years of fatigue when packing and unpacking heavy luggage, while the rest of the nylon construction remains as functional as the day I got it.

The buckles used here, with 'Rock Lockster' imprinted along the T-shaped guide, lasted for probably a few thousand clip-unclip cycles over the course of several years before teeth started to break off all the clips. The replacement I made is shown clipped in.

A good set of calipers came in handy in this situation, to measure the fit of these clips to make a compatible replacement. At first I made the base of the clipping teeth a little too stiff for my liking, after making it thicker than the original with the intention of extending its life, but one redesign fixed that.

My first and second versions respectively, in good quality save for the tiny blobs stuck to some sides as I hadn't tuned the extruder retraction quite perfectly.

This turned out to be a pretty good example for me of how well my reprap could handle creating something small and functional with quite complicated geometry to a workable standard of accuracy.

Later while trying to print out a Reprap Prusa-Mendel part that Adrian Bowyer modified, something sort-of cruicial broke on my own printer, making a slight mess of the part.

See if you can spot what was going wrong before I fixed it.

So it turned out that where the wires connected to the thermistor in the nozzle heating block, the use of a bootlace ferrule to crimp the tiny thermistor wire to the insulated wire meant that there was quite a sharp corner in the wire connection, and even though the set of wires going to the heating block didn't get tugged much at all during the x-carriage movement, the shaking about was still enough to eventually tear through that wire and break the connection.
Annoyingly, when the temperature-measuring circuit was open, it reported temperatures to the firmware program that bounced between about -20 and -8 Celcius, and instead of stopping the printer when the temp was negative, it carried on while constantly inputting heat to the nozzle. The result was that the overheated nozzle started dribbling plastic everywhere on movements through the air, while creating lots of fumes that stank the room out.
Thankfully I caught the problem before it was so bad as to ruin the print, and even saved it with a little bit of ingenuity; after switching the heater off for a while to let it cool back down to around a decent working temperature without the above effects, by observing how the open-circuit temperature was bouncing around I could see how to get it to self-regulate, so I set the target temperature to -12, thereby having it pulse the heat on-and-off again, managed to get it to finish the last bit of the print without any more trouble.

Bootlace ferrules and a little bit of heatshink, not good enough. In the background, you can see I had to take apart my x-carriage to get this extruder off, so have just printed new parts for it after I fixed this.

Of course, I can't just leave it at that for long unpredictable prints starting from cold, so I got a hand patching it up with some solder. Had I soldered the connections originally instead of using the ferrules that mendel-parts.com supplied me with, it might have lasted a bit longer, but I still think that joint would have given way eventually.
If anyone else is using an extruder that has a threaded heater block, with a 100KΩ thermistor that has teeny-tiny short and thin wires, I'd like to know how you connect it up, especially if you've found a way to protect the connection from being tugged while still easily being able to unscrew the heater block for maintenance. While terminal blocks can be good for quickly connecting/releasing a set of wires like that, the wires of my thermistor aren't long enough to fit one without it melting against the hot-end, not to mention that how thin they are would make it difficult to hold them in, so I'm a little bit stumped on this one.

Some other things I was working on prototyping included a replacement shower-dial for a friend where their original injection-moulded ABS part was slipping off the single shaft used for combined water/heat control, and a 'sheila maid'-style laundry drying rack. Not exactly spectacular or groundbreaking, but pretty useful at home.

Incidentally I made an observation of an unexpected plant use recently, when I pulled out the last of a few leeks I had bought quite a while ago, the last one that had been lying around for a while was starting to dry out slightly and wrinkle up. My other half decided that the outer leaves were too thin and 'papery' for her liking, even though it was being chucked into soup. Fiddling with the discarded outer layers, their consistency while there was still some moisture in them reminded me of thin sheets of expanded/inflated LDPE that I've encountered as a first (inner) layer of the original packaging for a flatscreen monitor. A moist material can't be used to package electronics of course, and I wanted to know how they would turn out once dried, so left a couple of leaves (when cut straight up the tube they are usefully rectangular) to dry over the back of a chair near a radiator.

Scribbling on the rougher side of very 'papery' dried leek leaves with biro.

After some messing about with the dried specimens, I've found that while one side is slightly ridged with the leaf veins, the opposite side is slightly smoother, and it makes a very good makeshift notepaper. A biro pen runs right over it with ease, although a 2H pencil that I had to hand quickly punctured it.
If supply lines break down somewhere currently oil-dependent and you don't have access to a paper-mill, this could be quite useful as it requires next to no preparation compared to paper made from minced-up plant fibre such as hemp or nettle - although I just chucked it over the back of a chair to dry, it might turn out less wrinkled if held taut in a frame. Of course with the natural veins, the material is anisotropic, in that it's quite strong along the grain and easily torn into strips by pulling across the grain; that property could have some use, but I haven't thought of one yet.

Digging A Small Swale

2012-02-07T22:46:00.002Z

Towards the end of last week I posed an open question to the awesome folks on the open-source social network Diaspora*, asking if anyone could think of a good way to visualise the relationships of beneficial/detrimental interactions between various plants. If we can figure that out, it might make my job of deciding how to arrange the smaller shrubby plants a lot easier, and similarly make it easier for anyone in future.
While I got a friendly response but didn't get any answers to the question itself that night, I updated my map in more detail, noting a few places where I thought various crops ought to be planted just as a draft, using freely-available information on companion planting available online, such as Wikipedia's List of Companion Plants, which unlike some of the other lists, is more likely to evolve over time.

Extra zoomed section on the left has a key along its left border.

I've had some thoughts since then, that maybe we could write a cloud-computing puzzle game, where players have to arrange plants on the ground (perhaps on a grid such as in the cute 2D game "Plants vs Zombies", only without the graveyard zombies), so that they get the best yields and ecological stability, counting the time/energy expended on things like earthworks, and perhaps calculating a score from that at the end. I imagine it having a learning curve of complexity where you start with small flat-ground puzzles and add elements like sun/shade, slope, wind, rain, soil type, etc.
The game could share results/scores like the Foldit cloud-computing program, over the web to server(s) hosting such highscores, using humanity's great capacity for lateral thinking to supply novel solutions to these problems to future permaculture designers. This is probably a tangent to be developed in conversation elsewhere though.

Sadly, the next day those bare-root fruit trees didn't turn up in the mail, so the fedex service used by mail-order trees kinda let us down a bit. Not having the trees to plant did give me a chance to start digging a water-harvesting swale, although planting them wouldn't have taken very long anyway, since I already had the holes pre-dug and covered over. (Since I got back to Glasgow, my friend told me that the trees didn't arrive until Monday, so I'm a little concerned about their health now.)

I brought something with me that I've learned should turn out useful after disturbing the soil.
Queue music.

So, I set about digging a swale just below the contour line that we had measured out, to give a good supply of water to the fruit trees where they will be below the swale.
Digging a water-harvesting swale is a fairly simple task once you have your line marked, where you have loose soil you can just shovel the earth up into a mound on the lower side, in this case where there were lots of tough grass roots, my approach was to repeatedly cut out blocks of sod in a long row, and flip them over to the lower side, on top of the grass to kill it down.

I started in the middle and worked my way east. One block is a start.

It was simple to start with anyway, but sometimes when digging in this highland soil, you find boulders...

...and they get right in the way of the fork & spade.

I dug along some more, went for a brew, and came back to pick up where I left; thinking I'd had quite enough of boulders for one day, I came across another one even more awkward than the first.

A wild boulder appeared!

I ran the swale off to the east end of the contour that we measured, and then turned it back slightly towards the hill, so that there was a cut-off and water couldn't get out there.

Extra soil mounded up to reinforce this point.

I had a closer look at that boulder, and it looks to be quite a big problem, since it could restrict water from passing by it along the swale. I did my best to dig around it a bit, but it was just too big in exactly the location that I wanted to put my swale, so I just hope that any significant water that gets in there will slosh over it.

I went back to where I started, just east of the bit I intended to be wide and slightly pond-like, and started to dig that out, heading north.

Here's the pond half-- oh wait you can't see that can you? I could.

Digging by moonlight (like a boss).

Again, with flash, the pond-like bit half-finished, with some more swale already dug further north.

Now with only moonlight left, since my friend was away at work all day and digging by yourself can take a while, I mounded all the earth in the wide section into a double-thick wall on the lower side, and ran the swale off to the fenceline.
Once there, I wanted to install a level-sill spillway so that if the swale was to fill up during a long rain event, any excess of water could be allowed to empty out passively by one side, without causing any soil erosion. Since I know that the fenceposts there are cast out of concrete with a big lump at the bottom as an anchor, I decided to bring the swale wall up against one of those posts, where the hard top of the concrete anchor would make a perfect run-off surface, even though I reckon that damn grass will survive almost any water thrown at it.

This part of the swale wall I piled up a little higher than normal and actually packed down tighter with my boot, so that it could withstand some water flowing past it.

I don't expect monsoon-type rains any time soon, but it's better to be safe.

As for the contents of the mystery jar, that was a mix of manure, water and pigeon/gungo peas, to repair the soil that had just been worked, fix nitrogen into it by growing in symbiosis with some of the beneficial root bacteria that I mentioned in my last post, and act as a cover crop to some extent so that the grass shouldn't take over again right away. I emptied them out thinly along the swale wall, and with any luck they should germinate in the warmer weather in the coming week and fix the soil until I get back to plant more veg.

Gungo peas, aka pigeon peas, a useful soil-repair legume.

I've had those peas from a big sackful for quite a while now, so I don't know if many will germinate, and then I don't know how long the warmer weather that came over as I was leaving will last for (this is probably better done in autumn), so any that do germinate might not last long, but something is better than nothing. I'll just have to wait a few weeks til I go back to sow seeds, to see the results of this bit of earth-surgery after the weather has affected it without my intervention.

How the ditch looked the next morning as a small rainstorm was blowing over (least-shaky picture I took)

I haven't measured it exactly yet, but from looking at the sketched contour, I guess the curve of the swale to be about 20-30m long, while the blocks I was taking out were for the most part 1-foot-cubes (30cm ^3) and a couple of points were wider, up to 4x that width, I estimate this swale is probably capable of holding something like 80-120 cubic feet of water while it drains into the landscape. Given the hilltop location and that the weather is usually quite steadily cold&wet but not often heavily rainy, there shouldn't ever be enough rainwater in one go to break the swale wall, but then that's partly why we want it there, to trap whatever bit of water falls on that hilltop.

If you'd like a good video tutorial on this sort of installation, check out "Harvesting Water The Permaculture Way" where Geoff Lawton took a bunch of permaculture students onto someone's land in Australia to install a rainwater-harvesting system about 10x the size of this one, including a dam. In that scenario they brought in the fancy surveying gear that I mentioned in my previous post, along with a backhoe excavator-tractor. I largely developed my methods from that video, scaling the example down to this situation appropriately. As was mentioned in that video, things don't always go exactly to plan once you start digging, and in this case the very rocky ground posed an interesting problem.

On a cheerful recycling sidenote, here's a little something I'll be testing soon when I sow spring crops, an alternate method to the early indoor sowing and later transplanting that is often advised in gardening. Some people might use 'cold frames' or big sheets of plastic to try and keep delicate plants warm while they get a little extra sunlight for an early crop, but this is my way of creating a temporary mini-greenhouse for them...

First, take a couple of empty soda-bottles:

If you had some nasty sugary stuff in them, wash them out first, and stop drinking that stuff.

Next, remove the labels and slice each bottle in a hoop around its centreline.

You can use either end of the bottle for this, and sturdy tent-pegs; I just used twigs for quick demonstration purposes.

Poke holes slightly back from the cut edge to push pegs through, you decide how many you want depending on how windy it is, and secure one of these over wherever you have sown seed for a vulnerable plant. You want the bottle that you use to be large enough to last until cold weather passes.

Taking Cuttings

2012-02-02T03:42:00.000Z

When you're trying to establish a stand of trees or bushes (or planting anything that germinates slowly, for that matter), a far cheaper and faster option than buying plants in can be to take cuttings off some overgrown branches of a friend's plants with their permission, and get them to root and form new plants.Ideally, when taking cuttings you should try to start the end that you want to root around one of the points at which the parent plant branches, and trim the smaller branch of your cutting back to that point, as for botanical reasons that I haven't bothered to research yet, the cells around such a node seem to find it easier to change their growth pattern into a root. You can also improve your chances by treating the tip that you want to root with a solution of 'rooting hormone', usually particular synthetic auxins that instruct the cells there to grow root structures.

In my case, to create a fast windbreak hedgerow, I have a couple of brilliant plants available for the job, where my friend and their neighbour have willow trees and blackberry brambles, which grow so vigorously that you can often just shove a stick in the ground and it will root. In fact, the former is so good at spreading by this method that it is considered an invasive weed in Australia, and my friend tells me that one time they tried to make a fencepost out of a freshly cut beam of willow, it grew into another tree where it was placed.

Having all that in mind gives me a little more confidence when considering that this isn't such a great time of year to be trying to root some things; all the ground was frozen hard and frosty on top yesterday, and it was so cold out that I couldn't get much done before feeling like my fingers would fall off if I carried on. I've read other gardeners saying that late autumn is the best time to transplant brambles, giving them a little time to establish roots before becoming dormant over winter, but I've done my best to get some roots going anyway.

One cutting from willow ready to be planted on right, trimmed at a join with a bit much bark stripped off but oh well, and another cutting on left showing where a branch would be cut before trimming it down.

I started a couple of days ago by cutting off some bits of willow getting in the way of a path, and digging very small holes for them to grow in by the south-west fence line. I added a tiny bit of manure in the bottom of the hole to help the roots establish, but without the bulk of extra soil from planting potted trees, there was practically no mound above these branch cuttings.

The previous cutting planted at top, the ground almost flat, with the next one trimmed down in the foreground, ready to be planted.

I was also supplied with the cheapest tree available from that native plants nursery, a Downy Birch, which with its affinity for slightly wet and acidic soils, should do very well in its position near to these brambles.

I found an impressively/annoyingly-sized rock in the hole that I was digging for it.

Then I remembered to take pictures of the way I'm covering pre-dug squares of sod for the bare-root fruit trees, which should be here when I get up ~~in the morning~~.

A section of some of the woven-appearance cupboard backing that I keep seeing more of these days, going a bit soggy and rotten, and held in place with bit of scrap bamboo, will act as mulch to suppress the grass roots in this patch.

Keeping the grass down should make it a little easier to plant the bare-rooted fruit trees in each patch when they arrive. Also doing this helps me to remember where I planned to plant them. If I had more bits of cardboard to spare, I would cover a wider area to make it easier to plant legumes around the trees once they are in.

If you can see them, these baby trees are getting all ready to make an effective wind-break now. The downy birch is the one ready leaning slightly into the wind, tied to a bamboo stake taller than itself. That big rock is also weighing it down for extra storm-safety.

Even if those willows try to overgrow and take over, they can easily be coppiced many times. A brilliant temperate pioneer plant, giving the benefits of a windbreak to other plants, while providing yields of useful timber and firewood, and even a natural painkiller/fever remedy (from which aspirin was derived).

The next day I took some cuttings of the nearby bramble bushes, trimming them in a similar way with some secateurs. To try and improve their chances in rooting and surviving, I used a budget trick learned from some nice pot-plant growers quite experienced in the art of plant cloning, by mixing up a little honey with some water and dipping the roots in it.

To make the process useful I did something I often do for an efficient brew, which was to pour water straight into an old honey jar that has had all but a thin film scraped out of it. Of course, in this case I used a little water left in a kettle after it had cooled down, so that it wouldn't denature useful things in the honey.

Some of a non-thorny variety of bramble, some not, one bit of another healthy-looking bush I didn't quite recognise, but seemed very hairy.

Once I had collected my cuttings and warmed back up a bit, I took them off to the patch to plant. I put the biggest cuttings into three separate stands along the fence, where I hope they will spread from.

My method for this was quite simple: kick the frozen grass aside, make a row of holes with one jab of a pitchfork, shove a cutting in each hole, water it a tiny bit and move on.

I left a couple of the smallest cuttings aside to be potted, as is generally suggested to be the safest way to clone any plant cutting, so even if my cuttings outside don't survive the end of winter, I should have something to transplant out there in the spring.

The leftovers, with crunchy grass in the background.

These little ones seem quite happy in their soft warm potting soil.

2013 Update:
Something I didn't fully know when this was published was that one of the main reasons why willow is so amazing at rooting itself, is that the greenish resin in its bark and spring shoots contains chemicals which both aid rooting at the same time as acting as a painkiller in humans. While the Salicylic Acid present both cures headaches and activates a plant's immune system to help fight off fungal infections, there is also a hefty amount of Indolebutyric Acid, which is a root-growth-promoting auxin.
Although solutions of honey, sugar or specially mixed electrolyte salts can keep cuttings alive for quite a while by providing necessary nutrients, and sometimes even allow them to form new roots, hence it's generally advised to treat cut flowers that way, if you make a tea out of willow bark or shoots and leave your cuttings in that overnight, it'll give them a much better kick-start to survive and thrive.

Permaculture Design

2012-01-30T02:42:00.001Z

Recently a friend has given me a great opportunity to try out a new design science, Permaculture, by developing a self-sustainable miniature food forest on an allotment in the Scottish Highlands. Studying permaculture design and getting ready to move out of the city over the next couple of months, has of course meant that I haven't had much time to do 3D design and writing recently, however moving soon also means I will eventually have more time and opportunity to test out my own wind turbine designs and other tech.

Having watched several hours of a wide variety of instructional videos and documentaries on various aspects of permaculture that can be found in many places online such as youtube, plus starting to read the first few chapters of Bill Mollison's brilliant "Permaculture: A Designer's Manual", I had enough grasp of the basics to start hashing out my first ideas and designs, and learn more as I go along by testing. My approach could be seen as 'jumping in the deep end', and while I would like to spend more time learning before acting, possibly even take a course on the subject, a constraint of time means that if I don't start implementing at least a few changes to this land immediately, then I'd miss the important winter period when trees can be easily moved bare-rooted and planted, while a constraint of money means that I wouldn't be able to afford attendance fees at most courses anyway.
Nonetheless, I agree somewhat with Mollison's thoughts in his manual that "Starting with a nucleus and expanding outwards is the most successful, morale-building and easily-achieved way to proceed." Where he and many others have advised that you can learn much by simply sitting back and observing nature, then testing any hypothesis of its workings, I hope that I can use nature as my university, as the ones with walls don't seem very conducive to learning.

First area of interest fenced off in the centre of this picture, see all that overgrown grass? Guess which way the prevailing wind is from...

My general plan is to take this small-medium hilltop allotment approximately 20m by 15m, within some larger common ground that is almost entirely smothered by grasses lying in their near-horizontal tufts under the strong prevailing wind, and sprout a small pioneer area of productive woodland, in a hope that it will produce enough mulch and attract enough wildlife to extend itself, producing a lot more food and other resources with some gentle guidance, but without the use of external energy (besides sunlight) or fertiliser. The target to remove dependence on outside energy sources is a main aim in most permaculture design approaches, and without large-scale renewable energy infrastructure, is quite crucial to sustainability.
This land used to be covered in forests for the last few thousand years until the increasing thoughtless high-energy industrialisation in the cultural detritus of the roman empire led to them being cleared for timber, fuel and to dedicate most of the land to sheep herding.
While it is clearly possible to have lively forest growing here, the afforestation that occurred after the last ice age would have taken a long time to move up through the land, as the current barren landscape can make it difficult for many plants to grow in the cold and strong winds, a bit of thoughtful help is needed to improve on nature's ability to colonise and stabilise harsh environments. Such brilliant examples of permaculture in action as the Greening the Desert project show what difference a bit of thought can make to nature's ability to increase the fertility of a region.

One good tool of planning, besides listing and considering the interactions of components (takes a long time to write down, not going to stick that in here) and the ever-important observation, is to create a map.

Partial elevation map of the patch and surrounding area; perimeter traced from satellite images and details added from direct observation.

The details on this map above were sketched simply from depth perception while moving around a small area, and the following photo shows some of the area that it covers:

Once I had some intentions set down, was able to access the land to see the lay of it, and began to gather some information about what types of plants grow well in this specific cold-temperate climate and how they affect each other, I was able to start sketching up a map of the area of operation, what was currently there in terms of topography (landscape) and outside energies (wind and sun). Since exact contour lines are very difficult to judge in a shallow-sloped sea of grass, I invented little V-shapes for my diagrams to mark slopes (points uphill, larger ones indicate a steeper slope), a bit like embankment marks on ordnance survey maps... except backwards.

Don't mind the scribbles on the left from uni, I like to re-use notebook pages.

My first main concerns were with the aforementioned two energies. Sunlight is in short supply in the Highlands, so I figured that trees ought to be initially towards the northern end of the patch so that they don't cast too much shade over any shorter sun-loving annual crops or shrubs that might be grown in places. Since there can be very harsh winds prevailing from the south-west, and some very cold ones when it turns to come from the north, I decided that putting some fast-growing pioneer trees to the south-west and north-west of any more cherished fruit and nut trees would be a good idea.

The locals had previously planted a bunch of pines as pioneer trees, I was considering doing the same until I examined these and found that the stormy winds had completely stripped the needles off the windward side of these evergreen trees.

I don't initially want to block wind to the entire fenced-off patch though, since its energy could be put to productive use while some of the baby trees are growing if I were to mount a wind turbine near the middle peak, even just to test one that could later get a better location. For this reason, and due to the current monetary expense of nursery trees, most of the south-west fence won't have trees along it for now. However, by planting blackberry brambles there, we should be able to reduce the wind slightly at ground-level, while their tendency to creep around and overgrow when untended, along with the presence of sheep to browse anything that grows through the fence, should allow them to form something like a hedgerow.

Using what I knew about the ground elevation, and after finding out what trees were available, I took another step in development of the design by laying out the trees in order of height and hardiness, and by designing in one of the most important elements to take control of when establishing a food forest, the collection/infiltration/runoff of rainwater.

Shorter-growing trees are on the sunnier side, while some fast-growing and hardy native trees are placed so as to block incoming winds. A potential location for a water-harvesting swale, pond and level-sill spillway are marked.

A swale dug on contour before the southwest fence on this part of the hill would be very useful, since the ground starts to drop away quite quickly beyond that fence into a sheep pasture field, and so catching it before it runs off the overgrown grasses, pacifying its motion and allowing it to soak into the soil, should allow local pioneer species and fruit trees to grow more productively with a reliably moist soil to draw nutrients from. I remembered from many observations of brambles while foraging through them, that they will grow vigorously right up to the edge of river banks, onto the very wet zone where reeds will then start to grow, so I know they must be a water-loving plant and will appreciate the extra fixed water under the south-west edge.

Once I had a workable plan, and we got hold of some potted native trees from a fairly local tree nursery in Scourie, while waiting for bare-root fruit trees to be posted in from elsewhere in the UK we planted those pioneer trees while there was good weather, to let their roots establish for a bit so that they should make effective wind-breaks into spring.

Things needed for tree planting.

The way we planted the trees is easily do-able with one person, but a friend makes the work go faster and easier:

First we raked back some of the grass on a patch where we wanted to plant one, to make digging easier and to give some mulching material to lay down afterwards.
Next we cut out blocks of sod with a fork and spade and laid them down to one side, taking care to gently pick out any loose earthworms that might otherwise get chopped up in the process.
After scraping out lower soil to an appropriate depth, checked by dropping the tree in, we dropped a small amount of old manure into the bottom of the hole, so that beneficial bacteria and fungus could aid in each tree's growth.
We removed the thin pot and dropped the tree into the hole, then packed the sod back in around it upside-down where it would fit, so that any grass left would decay at the bottom and become earthworm food.

Option 1: Cover loose soil with cuttings on top to smother weeds.

Option 2: Loose soil on top to keep cuttings in place as they break down.

The pile was covered at the end with the leftover loose soil and grass cuttings, then watered.

On a couple of trees we put the cuttings on after the soil, and on another we did it the other way around. I suspect the cuttings may blow away in the wind, and/or the compost-on-top version of this might get weeds trying to grow in it sooner, but I will wait and see the results.

A sort-of-final and important step to this process will be planting some nitrogen-fixing legumes in and around the site that we planted the tree, to out-compete the grasses for light, which would otherwise compete for nutrients in part of the trees' root zone.

A couple of the edible companion plants that I read are supposed to benefit tree establishment/growth, which should grow well in this area, are the artichoke (a type of thistle), and nasturtiums. I don't yet know which, if any, native trees function as legumes (though I know acacia serves that function, it is native to the southern hemisphere and not easy to get hold of here), so I may have to find that out by future observations of which trees do well next to others.

The next job that we took care of was to survey the ground for a water feature on contour. When digging a water-harvesting swale, it is a good idea to peg out a contour line on the hillside where you would like to dig it in. Normally you might use a surveyor's Dumpy Level, or a Laser Level to find points on the ground at the same elevation as a starting point, but such equipment is expensive for us to get hold of, so we developed a cheap-and-easy method that does a good job on such a small-scale project:
The materials you need are as many pegs as want to clearly show the curve of your contour, two poles that can either be stuck in the ground or stood on it in a way such that they reliably have their base at the same height (on or under the ground) with repeated movements, some string and a spirit level.

For the two poles, we used a couple of electric-fence posts that each have a spike on the bottom for driving into the ground, with a little foothold jutting out sideways at the top of that spike, making it easy to shove them in the same distance (so long as rocks don't get in the way, as they frequently did).

The method is pretty simple, but would probably be quite difficult to do on your own, unless you grow some extra arms to hold all the gear or find some kind of pole that stands upright steadily on its own:

Put your poles side-by-side, bases at the same height, and tie each end of your string tightly at the same height on each pole, such that it won't slip up or down with a bit of tugging about

We used just over a meter of string to prevent it sagging too much, but if it's too short then you can introduce significant errors from the larger number of measurements.

Place one of the poles on your starting point, preferrably with someone there to hold it, to make sure it stays as upright as possible with some tension on the string.
Move the second pole around the first in the general direction you think is level, put it down with the string pulled taut, and lay the spirit level on top of the string to check whether you are too high or low.
Adjust the second pole's position if necessary.
Remove the previously stationary pole and shove or hammer a peg into its position.

We had a mix of scrap bamboo sticks and electric fence posts, so we alternated them to make the contour stand out with the bright-blue plastic posts.

The pole that was moving is now the stationary pole, so pivot the other one around it to find another point on your contour.
Repeat until you run out of pegs.

The result we achieved was even better than expected with this idea:

Given how rocky the soil here is, we probably won't be able to dig a pond for a permanent water store unless we can bring in some clay or concrete to seal the bottom of it.
The next jobs will be to dig in the swale, plant the fruit trees and plant some legumes as the weather warms up. I may have arrived here too late to plant a cover crop before planting the trees, but I'll still give it a go and see how they fare with an early spring planting. My next post might go back to something more mechanical depending how much work I do on each area.

Salvaging an Inkjet Printer (and other broken hardware)

2011-12-05T04:06:00.000Z

This was interesting enough that I thought it deserved its own post (and even more picturific than the last one).
Like on many occasions while living in the city, I recently found some old broken electronics chucked out of someone's flat before a day when the city council sends round workers to pick up bulky rubbish like broken appliances and furniture (it seems almost nobody knows how to repair things anymore, or they are too busy watching TV to do it).

First I picked up another halogen heater that broke at the base and was produced of even more plastic than the previous one I found, this time made by Hyundai (yes I'm naming names, you wasteful b*stards) yielded another synchronous motor that I could use in a rotary hydroponics prototype.

Were your amazing cars selling so poorly that you had to move into another market of things that break down quickly? The power supply on the left was torn out of something else...

Even better, I found a not-very-old inkjet printer that had clearly stopped working in some way, as a previous owner had booted in the side of it, so there was not much point attempting a repair.

Perhaps I should have taken this photo before stripping it apart, but curiosity got the better of me.

My suspicions were confirmed when I found some components showing a lot of wear, that this thing had probably gone well past its warranty, if it ever had one.

Cheap synthetic rubber cracking up?

There was something I remembered hearing a long time ago at one point in an interesting documentary about planned obsolescence, called Pyramids of Waste; that was how a printer had been designed to return an error after a certain amount of printing, on the basis that some sponge under the carriage, which was there to eject ink into in order to clear the nozzle, would have become clogged up with wasted ink. I didn't believe at the time that many printers would have such a wasteful feature, let alone a killswitch based around it at the firmware level, but lo and behold, at the bottom of this printer was a big felt pad soaked in copious amounts of wasted ink.

Anyway, as I took apart the very complicated structure of the printer piece by piece, I came across a wide assortment of different parts, some of which are shown strewn across the floor here in a filing system known only to Heisenberg:

Most importantly, I found some springs of different sizes, which will have all sorts of uses.

A variety of switches, including mechanical and optical ones; useful to robotics projects.

There were a couple of fine-toothed timing belts:

...and that thick bar was ridiculously greasy to make up for the rubbish bushing that was formed into the print-cartridge carriage:

Naturally in a printer, there were a few DC motors, but these aren't the more expensive, robust, and controllable stepper motors that you use in CNC machines...

Four in total, two of them attached to side brackets here.

If anyone can identify what spec. these motors are, that would be cool. The power supply quite strangely output 24V and 36V DC lines if I remember correctly. The markings on the motors however divulge nothing about electrical input or torque output.

I did my best to get this next picture in focus, a difficult task with my tiny-lensed phone camera; what you can barely see if you open the full image here is what that grey line around the transparent disk is. It's actually a series of very narrow evenly-spaced black stripes packed so close that there are a few in every millimetre of circumference. It is one cheap example of an optical rotary encoder, in this case not giving absolute position but only displacement to the printer controller, by counting how many lines go past the optical sensor on the left.

I also found a few different sizes of smooth bars by the end:

The grey marks on the lower bars are from where I pulled off spongy rubber rollers similar to the ones on the top bar, using a pair of pliers.

Oh look, even more springs came out!

Now in their own wee baggie for spare springs, which previously contained some of the smaller parts that built my reprap.

All this goes without mentioning the pile of assorted screws holding these things together that you can always get just from taking them apart, whether you use the rest or not... oh, and lots of odd gears, most of which aren't at all useful due to their weird mountings.
At the end of this particular salvage operation, I looked slightly like I'd just raided an ATM, but it was lots of fun.

On a related note, the only power tool of my own that I've been using up to now broke the other week around the same time; that was my cordless rotary tool from Dremel.
The blue switch-dial in the picture below no longer 'clicks' as it moves on/off from the zero mark, and consequently no power gets to the motor. I don't know what about the switch has caused it to break, although there is a peculiar hole in the side of it, that almost looks like something might have fit in there, yet there were no parts rattling around when I opened it.

Worked fine until 6 months after the warranty expired. Who could have guessed...

If anyone can figure out what might be wrong with that switch, what component it could be replaced with, or another way to hack a compact variable-voltage supply from the battery, I would be really grateful. Otherwise I might just replace the whole control circuit with a simple on/off switch and have it do two speeds; stationary and ridiculously fast.
Either way, take this as a firm anti-recommendation of Dremel's products.

While Sod's Law=True; Something Breaks; Fix It; EndWhile

2011-12-04T05:36:00.002Z

The last few weeks have been eventful, apart from turmoil in personal life, I've made a few changes with my reprap, and taken bloody ages to get round to finally blogging this. There is still more to come afterwards too, so stay tuned.

My Adrian's Geared Extruder got jammed (again) so I took apart that old extruder to replace it.

White ABS quite stained from heat and fumes. I've seen this before somewhere.

The filament drive was quite clogged, and after later cleaning it out with a brass brush I found that it wasn't just that grip had been lost and clogged it, the notches on that brass M4 insert really had started to wear out and dent flat in line with the filament path.

That part having been squashing and grinding at the plastic as usual, this came out:

So, with a bracket that I customised for shorter bolts from another design someone sent me, I hobbed an M8 bolt and constructed a Hinged Accessible Wade's Extruder to GregFrost's design.

My first attempt, not too bad (moved along slightly at one point when I found a slim washer that would allow me to cut at a better distance along the bolt), though I did another one later that was better.

I found that the hole for the PTFE insulation was too small, and after beginning to try and carve it bigger, thought 'screw this' and plugged the hole with a piece of bottle cork with a hole drilled through. :)

The oversized cork later got squashed very slightly as it took up the compression from the hot-end fixing bolts.

I found that this extruder actually wouldn't fit on the regular x-axis carriage due to the PEEK block orientation; I earlier thought it would be OK when looking at how the bolts would sit in relation to the carriage insides, but didn't realise that on installing the extruder, the top of the PEEK block would be higher than the bottom of the x-carriage, so it couldn't fit in there. :(
For a temporary X-axis I used Prusa's standard one for PLA bushings, since I had a spare one sitting in a box that looked ugly due to previous problems with backlash.

So far so good...

I started trying to print the final version of a clip that I had been designing for a while to go on top of the accessible extruder and stop the filament coming in from being bent too far to the side out of the hobbed bolt's grip (since there is no filament guide to enable easier cleaning, hence the name accessible extruder.
Annoyingly, the extruder started to jam when I was trying to print with PLA, and a few other things that I tried to print did similarly.

An earlier design for the clip that didn't work well due to the axis it was printed in (the bottom print surface is on top in the picture, and the bolt clip snapped off by delamination/peel stress).

Unusual about the picture above; the extruder seems to be designed to use M3 bolts to push the idler in, but I couldn't find any long enough, so I cut the captive nut holes out to M4 size and used the bolts pictured above. The spring was the stiffest small spring that I had on hand at the time (before I took apart the old extruder).

Bases of a pulley that I wanted for my x-axis idler, and the filament guide, on the left and right respectively.

When I went to the reprap IRC channel for troubleshooting suggestions I was advised to thoroughly clean out the extruder nozzle using acetone to help, since it seemed to take a lot of force to push filament through it by hand while hot, though I couldn't accurately remember whether it had always needed that much manual force.
I soaked the nozzle in acetone for about 3 days while very busy with other things and when I got round to taking it out, I found that there was still a significant amount of undissolved plastic stuck in there, which was mostly easy to remove with hand-applied torque on successive sizes of drill bit.
The nozzle outlet, which is 0.5mm in diameter, was a pain to clear out as I couldn't find a pin or needle that thin anywhere, let alone a drill bit, so I eventually used a short length of copper wire from a bag of scrap wire insulation that I'm hoping to find a sensible way to dispose of.
Very frustratingly though, upon trying to put the hot-end back together, I found that the threaded end of the PTFE insulation no longer fit the thread inside the brass nozzle, and was starting to strip the tread when I tried to put it in.

PTFE? Warping? Oh right, yes that does happen sometimes. -_-

It looks like I ought to get another insulation block as spare, but anyway after much messing about trying to find the correct thread size to re-cut it (needed an M8x1.25 die if I remember right, thanks again pete) so that it would fit properly, I got the extruder back together to try again.
While trying to run a print again, I wasn't happy with how much friction the PLA bushings add to the sliding of the x-carriage, and how loosely they held onto the smooth rods, so I decided to design a new x-carriage with the combination of properties that I need.

When I came round to trying to print parts for my new x-carriage in ABS, I was faced with a couple more extruder failures, so I tried successively reducing the distance that filament retracted during moves from about 1.2mm down to 0.8 then 0.5 without it helping much, also increasing the target printing temperature from 240 to 245C. Sadly, this didn't help, and I was unconvinced that the clogged nozzle was my main problem, as on trying to manually push filament through the hot-end again, it seemed to be just as difficult (though easier at slightly higher temperature, hence trying that).

The filament drive definitely wasn't gripping evenly; sometimes extruding, sometimes not. That made it difficult to calibrate...

Eventually I tried a combination of reducing the retraction distance hugely to 0.2mm, the print speed to 30mm/s, and replacing the small extruder idler spring that I was using, with one of the 4 larger ones that originally held the idler on my old extruder, as I had a hunch that maybe the spring I was using wasn't applying enough pressure, against the advice I had to the contrary. This solved the problem of the extruder jamming just nicely, albeit producing quite a few loose threads of ABS in the print.
However, a short while into the print I noticed a couple of other problems; with the spring now making the filament drive tight enough, too much plastic was being extruded, making the extruder bump against layers of plastic in . I ended up sitting by the printer alternately using one hand to hold the carriage onto the rails, and the other to draft this post, for nearly 2 hours. That's not something I want to do again in a hurry.

When we talk about repetitive labour...

Part of the way through I even innovated something to make the job slightly less tedious (though still very tedious), as the way I was mounting my cooling fan before (too small for the holes on the carriage which were for a 40mm fan), was allowing it to drop down too low, cooling the hot end too much when I wanted to keep the filament drive and motor cool. So I did this:

Wire twist - easily installed with one hand (obviously I took this picture afterwards)

Here I show the dodgy carriage and express my thoughts on the situation:

Eventually I got this result:

Fugly and stringy (until I cleaned it up, then just fugly... but usable)

I put my new x-carriage top together with the old bottom part, and on trying to fit the extruder was reminded of why I was using the Prusa carriage in the first place. While I had made plenty of room in the top part to turn the extruder around, the old bottom part didn't have room for the diagonal alignment of the PEEK block on the hot-end, so not to be set back anymore, I had a go at the part with my pen knife.

It works... what more do you want?

Finally, order has returned to the system (for now) and it's working better than before, since my re-designed x-carriage allows the timing belt to be tightened on-the-fly using a neat trick that I've seen used on a couple of other designs now; an M3 nut and bolt embedded in the belt-clamp:

The new carriage has mounting holes for both this tiny 32mm fan, or a 40mm one :)

Since testing by printing a few standard Prusa structural parts, with the filament retraction returned to normal, it seems that spring pressure was the main issue here.

Good news on a design front though... I've finally got round to starting to do some CAD on printable parts for a cowled wind turbine, having only had ideas for it stuck in my head and a few scrawled sketches so far, while a group in Michigan Tech Uni have made what sounds like a better attempt at a relatively cheap plastic recycler/extruder, for which I hadn't thought of a good way to drive filament through yet, after mentioning the work of Delft Uni students before. So if their system works well and is easy to source parts for, I might not have to worry about that anymore. :)
I've also recently met someone else through TZM who seems interested in coordinating a project to start prototyping DIY rotary-hydroponics solutions into something we know works and is easy to build, which we hope can get the assistance of Douglas Mallette, as I hear he's also interested in developing that.

The First Part to Break on my Reprap Mendel

2011-10-16T00:02:00.000+01:00

When I started a print today I was confused to see the first layer of plastic getting squashed down very flat, so that it was noticeably thinner at one end in the Y-axis. When I stopped this and checked what was happening with the extruder movement, it seemed as though the bed had lifted up at one end, which was confusing since there was no way for the sprung bolts supporting the bed to have unfastened with nylock nuts on them.
However, upon investigating a strange rattling noise that I was hearing on the opposite side of the printer, I found this:

y-bearing-180-outer-right

It seems the torsion exerted on that square projected section holding the bolt that supports the bed was too much for the plastic, after the fatigue left by printing a few kilograms of plastic over 6 months, especially with the heavy 5x230x230mm aluminium plate being supported by the corner bolts.
It's an uncommon failure mode - many FFF 3D-printed things can break if they are subject to a stress that tends to peel layers apart. Normally they should be fine with a reasonable stress acting in the X-Y plane that the object was printed, but here the sharp corner at the bottom of the bolt support has probably caused the stress to concentrate there.

It looks like I'll have to glue the part back together and print a new one, since funnily enough with all the parts I've been printing for the Prusa Mendel, I haven't made spares for such structural parts on my own printer, not knowing that this part would break so soon, having forgotten any worries I had about the part when first assembling the Y-axis.

X-Axis Improvement Update

2011-10-12T18:51:00.001+01:00

Having printed a few Prusa Mendel parts since modifying my x-axis, without changing any settings, I have now seen a very slight improvement in accuracy:

Left: Greg's Hinged Wade's Extruder Idler turned out the best I've printed yet, where the top-most section forming the hinge can sometimes be troublesome as it is such a small area, Right: Z-Motor Brackets have a slight blemish on the inner surface, but no layers going significantly out of line

Top: Prusa X-Motor Bracket is as straight as ever on tall flat sides, not much more bumpy than the squashed layers of plastic inevitably produce, Left: Complex geometry on Greg's Hinged Extruder Body with overhangs turned out ok, Right: Extruder Driven Gear printed fine, as close to a perfect circle as I've had yet.

No strings attached to any of the parts needing to be cleaned off, due to having already tuned the retraction settings to balance clean prints without jamming the extruder.

Still a way off the greatest example I've seen yet though:

Looks like the the left (tony buser's labour of love) uses a finer filament, probably 1.75mm feedstock. Story behind this here.

Mendel X-Axis Upgraded

2011-10-03T20:36:00.005+01:00

Difficult to see here: M3 nut torn away plastic around it, as its slot was too shallow to pull it out of the space the bar goes through, so put too much torque on it trying to squash plastic

So my original x-axis modification design didn't quite go to plan as I found a couple of weaknesses in the prototypes, which didn't print brilliantly in the first place, but after putting wider tolerances in places, for instance making the spaces next to the smooth rods for M3 captive nuts 1.5 times as deep as they should be, I arrived at something much more robust.

That most significant change on the captive nut slots isn't visible, but the area directly around the motor bolt holes and the slot for the idler are reinforced with more material.

The belts are currently wrapped around the adapter a bit due to having several inches to spare after changing the axes, but I didn't want to clip them yet in case I wanted to go back and make any other modifications to the new design.

The new x-axis arrangement.

I ran another test with my very first printed object, the open rectangular box, which should have an ideal outside measurement of 60mm by 30mm, and it printed fine (unlike my first test ever) producing a box with outside measurements of 61mm by 31mm... until, that is, there was a random problem with the extruder getting a bit jammed, which is fine timing considering I've nearly finished building my hinged wade's extruder.

The end result, the new one holding the voltage-selection diodes that came with the power supply I got from mendel-parts:

Earliest and Latest prints, separated by half a year

Mendel X-Axis Redesign

2011-09-25T02:01:00.001+01:00

I was recently noticing a significant problem occurring in my prints referred to by makers as 'backlash', where some plastic deformation (permanent damage) or slack in the timing belts driving either of the X and Y axes, can lead to the extruder or printbed stopping at a slightly different real location for the same instruction, depending on which direction it moves there from.
This can be more technically termed a physical 'steady-state offset' in the way the extruder head, or any robotic part experiencing friction or loose parts for that matter, comes to rest after a movement.

Early indication: Note the ridges out of line on the near-left face; structurally insignificant here, but quite visible.

So I set about trying to fix this with some tests in PLA. I created a simple test-print of a 25x25mm square and 25mm diameter circle wall next to each other so that I could measure them with calipers and see how the real object compared to the design.
Since this problem can sometimes be caused by a pulley working itself loose from a motor shaft, I first tried tightening up the grub-screw holding the x-belt pulley in place. This made no observable difference so I turned my attention to the belt.

While the next test print was running, I observed how the belt fed over the pulley as the perimeters were drawn at low speed, in case there was any damage to the belt. What I noticed was that at a certain point along the belt as the extruder turned around the circle, the belt would suddenly slip across the pulley by almost half a tooth-length as it wasn't meshing properly. At the exact same time, the extruder jolted to one side by a tiny amount, causing the line drawn to not weld properly with adjacent layers.
The resulting malformation can be seen here:

Also notice how squashed the original 'square' is in the X-axis.

My next remedy for this was to take the x-belt out and swap it around, since the pulley teeth only ever saw half of the belt during its full travel, I guessed that using the un-worn half of the belt would allow it to grip better. I also noticed while taking the belt out that there was some very slight wear on the ABS X-axis pulley, so I relpaced that with a spare.
This helped for a while, resulting in the print improvement that you see above, although the problem started to creep back in recently, so I suspect that the belt is nearing the end of its service life and may have to be replaced before it snaps.

In the interest of reducing this problem in future, and also getting rid of the annoying round-four-corners path followed by the Mendel X-Axis, even with its main alternative design to decrease belt wear that I happen to use, I have been designing new end brackets for the X-axis, with the belt travelling in a similar simplified style to the way Josef Průša completely redesigned it, however this will still be compatible with the old Z-axis fittings of the original Mendel. This should shorten the belt needed, thereby removing some of the flexibility, while simplifying the construction of the axis slightly.

The first prototype, bottom-right part had issues due to the extruder gradually losing grip during print.

The parts for this redesign are here, and tomorrow I should be fitting and testing this system, so I can update how this goes then. If all goes well, then hopefully I can build a better extruder with the steel fastenings I recently got, and complete another set of parts to sell so that I can replace the belts before they snap. O_O

Why Didn't I Think of This Sooner?

2011-08-23T21:29:00.001+01:00

Recently I'd been having an occasional problem when leaving my reprap unattended, especially if there was a big new reel of plastic on that barely fit, where the filament being unwound into the extruder would be close to the outer edge of my spool.
After a while of being pushed and pulled with the printhead movements, since the friction on the PLA bushings I used in the spool hub had such low friction, the filament would unwind itself loose enough for one loop to flop off one side of the spool, get caught on something and pull the extruder carriage to one side, skewing the whole piece being printed.

A lad on the reprap IRC channel going by the name DavideV tells me he uses some fancy piece of kitchenware called a Perfect Tear Paper Towel Holder to hold his spool, which apparently ratchets around in one direction providing some tension with a spring to stop kitchen paper rolls from unravelling. I looked around for other similar products to try and find a simple mechanism that would keep my filament in place, and one was simply using this method of pressure:

SimpleHuman "Tension arm paper towel holder"

Which inspired me to create this:

My Bungee Cord Plastic Filament Retainer (BCPFR) needs to be on quite loose so that it doesn't create the same problem that it's intended to solve.

Glory be to the gaffer, the bungee and the methylated spirit, ramen.