Confessions of a Fireworks Man

Making Rocket Nozzle Mix

2008-02-15T08:45:04-08:00

This article was provided by Ned Gorski.

If you look in the end of most black powder rockets, or at the end of a gerb (fountain), you'll see a clay nozzle recessed into the end of the paper tube.

A Clay Nozzle In Paper Rocket Tube

A nozzle is a mechanical device with a hole in it, which controls and directs the flow of a liquid or gas as it passes through it. Think of the nozzle you put on the end of your garden hose. It controls the water flow, builds up higher pressure in the hose than would normally be there, and projects the water out in a nice stream. A rocket nozzle does essentially the same thing with the combustion gasses from the rocket motor. This is what propels the rocket skyward.

Typically, the nozzle in a rocket, and the solid plug at the top of the rocket motor's fuel grain, is a rammed (hand pounded with a mallet) or pressed (with a hydraulic or mechanical rocket press) mixture of wax, clay, and grog. Some folks use only clay in their rocket nozzles.

I did that for a while, but found that the clay nozzles were very susceptible to shrinkage/expansion, depending on the day's humidity. One time I pressed a bunch of wheel drivers with only bentonite clay nozzles, here in the Midwest hub of humidity. Then, when I got out to Gillette, Wyoming, which was so dry my lips started cracking, my nozzles got so loose in the rocket tubes that I could turn them with my finger. (I quickly added a ring of Elmer's glue where the clay nozzle met the tube to secure them.)

Some folks expect their rocket nozzle apertures (hole) to close a bit with the clay's expansion. So, right before flight, they open the hole up to the correct diameter with a hand-twisted drill bit. Adding wax makes the clay much less prone to this problem. Also, the clay alone, when pressed, forms a smooth, glossy surface; and nozzles and plugs have been known to get blown out of the tube by the pressure of the fuel burning. The grog in this rocket nozzle mix really helps the nozzle 'bite' into the side of the rocket tube and resist blowout.

The grog also helps the rocket nozzle resist erosion of the hole during motor burn, whereas without the grog, the clay can wear away some and the nozzle aperture (hole) opens up some during the motor burn, which reduces pressure and thrust.

The technique I use to formulate these ingredients and mix them together is similar to the one David Sleeter recommends in his Amateur Rocket Motor Construction book.

I get the wax that I like to use from the canning supplies department of my grocery store. It reads "Household Paraffin Wax, for canning, candlemaking, and many other uses." (I'm not sure why they don't list rocket nozzles on the box as one of those uses.)

Paraffin Wax for Making Rocket Nozzles

I either use bentonite clay from Skylighter or Hawthorne Bond Fireclay. They are both very fine, powdered, dry clay. (When I first started making rockets, I imagined that 'clay' should be like putty, or that I had to turn the dry clay powder into a 'play-dough' by adding water. We live and learn. No water is ever added to the clay.)

Grog is a man-made, sand-like product. It is made from fired pottery that's been crushed and screened. One well known rocket maker uses crushed red-clay flower pots. Another uses busted up and screened ceramic floor tile. I get my fine-medium grog from my local pottery supply house. Skylighter sells grog which has fine, medium and coarse (up to the size of peas) particles in it. To use Skylighter's grog, I screen out the coarse grit to end up with something that looks like fine-medium sand. A fine-meshed kitchen screen colander works well for that.

For a batch of rocket nozzle mix, I weigh out:

- One of the 4 ounce paraffin wax blocks from the box
- 30.5 ounces of the clay
- 15.5 ounces of the grog

Weigh Your Clay and Grog

Now, I add the clay and grog to a new, clean, one-gallon paint can that I get at Home Depot. After installing the lid, I shake the can to mix the two powders. Then, I open the can, make an indentation in the center of the dry mix, and lay the block of wax in the indentation.

Place Block of Paraffin Wax in the Can with Clay/Grog Mix

I then lay the lid on the top of the can loosely. (Caution, do not put the lid on tight. Pressure can build up during the heating and either burst the can or pop the lid off, sending wax and clay everywhere, and possibly causing injury.) The paint can, with the loose lid, is then put in my oven, set at 250 degrees, and cooked for about 1-2 hours or until the paraffin wax is completely melted into the dry clay/grog mix.

Heat Can at 250^o for 1-2 Hours

I don't use my kitchen oven lightly for this project. In fact this is the only time I do use my oven in my pyro pursuits-for cooking rocket nozzle mix. I absolutely never use it to dry or heat any pyrotechnic compositions. Never. And I keep the heat in this process down at 250 degrees to prevent the wax from igniting. Please, be mindful and careful.

Once the paraffin wax has completely melted into the dry mix, you'll see that it has only dampened about half of the clay/grog. The other half is still dry. This is remedied by removing the can from the oven with oven mitts (believe me the whole rig is hot) removing the loose lid, and stirring all the ingredients with a paint stirring stick until the wax is well incorporated into the dry mix. During this stirring, I only grabbed the can without an oven mitt once.

Mix Melted Wax with Clay/Grog Thoroughly

After stirring the nozzle mix with the stick, I install the lid, tightly this time, and, holding the can with oven mitts, shake the can violently to really incorporate the wax into the mix. Then, while the mix is still warm, I open the can and screen the mix through an old, wire mesh, kitchen colander onto kraft paper and let it cool down completely.

Screen Mix to Remove Lumps

This screening process really helps further integrate the wax into the mix, and also removes any waxy lumps which may form, which I just pitch out. The finished nozzle mix product will look like a tan, medium grained sand. I put it in an empty 5 lb. plastic chemical tub marked 'nozzle mix.'

I have another tub marked 'bulkhead mix.' This mix is the same as the nozzle mix, but with the grog portion simply replaced with more clay. I use this bulkhead mix in many driver and rocket motors, where I'm not concerned about needing the grog in the bulkhead (top clay plug) to prevent blowout. The advantage to this mix is that I can easily hand-twist a drill bit to create a passfire hole in the plug. Mix with grog in it, is very difficult to twist the bit through, and the bit would get very dull quickly.

So, let's pound a nozzle up, remove it from the paper tube, and see just what sort of component this new nozzle mix will produce. Whaddaya say?

Using a Skylighter, one-pound, 1/4" wall rocket tube (TU1068), some one-pound rocket tooling (TL1211), a rawhide mallet (I swear by this mallet), and a 6 x 6 x 4 ft. tall 'pounding post,' I'll pound a nozzle into the rocket tube, using a heaping 1/2 tablespoon measuring spoon and a funnel.

You might notice that black rubber O-Ring (from Home Depot) I like to use around my rocket tooling 'drifts.' Between Skylighter, Home Depot, and the kitchenwares department of my local department store, I get enough stuff to stay busy forever. The O-rings really help keep dust down. But, thanks to the wax, my nozzle mix is not very dusty to begin with.

One nice tip, which I got from Tom D, is to soak the rocket tubes in Minwax Wood Hardener and let them dry. This will strengthen the tubes and make them more fire-resistant. I'll dip the tubes into a can of the hardener, let them set there for a minute, remove them, and stand them on end on some plywood scrap to dry.

Rocket Tooling - Note Black
O-Rings

Ram Mix into Rocket Tube with Nozzle Forming Tool
and Mallet

8-12 nice whacks with the rawhide mallet and the rocket nozzle mix is well consolidated. Now, to dissect this nozzle a bit, I use a coping saw to cut the paper rocket tube off right above the nozzle, and slice the tube on both sides of the clay. You can see how the nozzle mix has consolidated into a solid mass, bulging the inside of the tube out just a bit in the process, which really locks the nozzle into the tube.

Cross Section of Cardboard Tube Showing Nozzle

Nozzle Removed from Tube

If you tap a metal spoon against the side of the clay nozzle, it 'tinks' like a little piece of solid ceramic. Nice.

In the future, we'll have an article on how to build a one-pound, black powder, charcoal-tailed rocket based on the foundation that has been laid in this article. One really nice thing about these rockets is that they provide great pyro and immediate-gratification, even in the winter months. Make up some nozzle mix, blend together some fuel, pound a motor together, attach it to a stick, and take 'er outside to fly. Smell the Smoke.

Have fun and Stay Green,

Ned Gorski

How to Make Yellow Glitter Firework Stars

2008-02-15T08:04:21-08:00

Click Picture to Enlarge

Photo Courtesy of Tom Handel

Glitter is That Silvery Twinkly Part at the Bottom of These Brocade Firework Shells

This is a gold brocade firework shell. Glitter firework stars are hard to depict in slow-shutter-speed fireworks photographs, but you can get an idea of how silver glitter firework stars might look like in the sky if you enlarge the photo above (with a click).

Here's a good formula for making yellow glitter firework stars from Bob Winokur. Bob wrote the greatest treatise on making glitter firework stars and comets, Pyrotechnica 2. It's probably the most complete study of glitter firework stars ever done. This article ran in the August 1992 issue of the First Fire, the Florida Pyrotechnic Arts Guild's exceptional newsletter. Thanks to FPAG for letting us use this, and Chris Miller, for writing it.

Yellow Glitter Firework Stars
by Chris Miller-WPA

I originally got this formula from Dr. Winokur a few years ago as a universal (good for all occasions), "state of the art" yellow glitter. It has a long delay and can be used in any size firework star, from 1/4" t o 3." Firework stars 5/8" and smaller tend towards the "glitter cloud" effect and are great in shells by themselves or mixed with color firework stars in a volume ratio of 3:1 or 4:1 (color : glitter). Firework stars 3/4" and larger leave long, beautiful tails and are particularly suitable as either regular comets or crossettes.

Assuming the ingredients are lump-free, sieve the mix three times through a 20-mesh screen (window screen works fine) and bind with 8% water. This isn't a lot of water so you should knead it for several minutes to insure that the water is well incorporated. Because of the antimony sulfide, I wear a respirator when mixing the dry ingredients and latex gloves when adding the water (I'm told antimony poisoning is akin to lead or barium poisoning-very unpleasant and I don't want to find this out first hand!)

Priming is not required for these stars although some people like to prime the stars when going for the cloud effect. It is also a good idea to lightly prime the exposed face of crossettes made with this glitter formula because there is a lot less exposed ignition area on a crossette compared to a regular firework comet of the same size. Priming is cheap insurance against one or two of the stars being blown blind and diminishing the symmetry of the break (not to mention wasting all that labor that goes into making each crossette that didn't work).

YELLOW GLITTER FORMULA
Chemical	Parts by Weight
Potassium Nitrate	48
Airfloat Charcoal	9
Sulfur	11
Aluminum (12-20 micron, atomized)	9
Antimony Trisulfide, Chinese Needle	10
Sodium Bicarbonate or Sodium Oxalate	9
Dextrin	4

Winter storm wallops Chinese & US fireworks making

2008-02-01T11:34:24-08:00

February 1, 2008

How today’s weather in China could impact your July 4th fireworks

If you are making fireworks yourself or are a consumer of Chinese fireworks, what is happening in China right now, today, will be affecting you.

The man who makes many of Skylighter’s Chinese fireworks products possible is Matt Palaszynski. Matt has a company in Liuyang. Liuyang is basically the center of the fireworks universe. He splits his time between there and his home in the US.

Matt works with each factory making consumer fireworks for us. He also helps us find all sorts of wonderful things we need in making fireworks. Things like screens, comet and star pumps, ematch blanks, the wonderful array of colored effect fuses we carry, and many other items that we now consider essential to fireworks making.

Matt sent me the following note yesterday. It affects all of us who are concerned about buying and making fireworks for July 4th and other events. This year, the fireworks industry worldwide is experiencing the most significant cost increases in a decade. Matt’s note explains graphically why some of these increases are happening, even as I write this.

Matt’s letter:

Hello,

I would like to update you on the weather situation in China as well as the impact on your order.

Central China is experiencing the worst winter storm in 30 years. For the last two weeks the weather has been poor and has been causing disruption to production. However, several days ago much of central and southern China was hit with an exceptional winter storm which has knocked out major power grids and shut down most transportation arteries. The forecast is for the weather to remain poor for at least the next week.

At this point, all production and transportation has ceased until at least mid-February. For those of you that were expecting shipments before Chinese New Year for arrival in March, the weather will delay your shipments.

For everyone else, production was progressing in January and shipments planned for late February and March are not likely to be significantly impacted. However, expect a delay of a few weeks vs. where we would have been without the poor weather. We were prepared for a difficult spring due to the Olympics and therefore, our production is ahead of schedule vs. typical years.

The storm is of natural disaster portions and will likely have some direct impact on the Fireworks Industry in the form of further RMB/USD appreciation. The poor weather is crippling food and fuel movement at a time of the highest annual consumption due to the holiday.

Because of this, food and fuel prices are climbing and the government is responding by allowing further appreciation of the RMB [the Chinese currency] in an effort to combat domestic price inflation. This means the RMB is likely to continue to appreciate further, further increasing the cost of importing fireworks into the USA (source China Daily Business Section, Feb 1st, 2008). Currently the RMB is at 7.19 per dollar, down from 7.5 at the beginning of the production season.

I personally have been in Liuyang since January 10th and was delayed in leaving for several days due to the weather. All roads and airports were shut-down. I just managed to get to a warm Beijing hotel room only after waiting with tens of thousands of other stranded holiday travelers for a standing room only seat on a local train.

The normal 12 hour trip took 18 long hours and was truly a once in a lifetime experience that I seem to have all too often here in China. Back in Liuyang, my team is struggling with below zero temperatures and only have a few hours of electricity (and heat) each day.

Under these conditions, we have given up on making any progress at production and the team has started their own difficult journeys to visit family and begin the most important Chinese Holiday.

Chinese New Year is an unusual holiday for us in the West to understand because all of China is shut down for several weeks. Many workers in China have left behind friends and family in the rural areas of China to work in and around the cities. During Chinese New Year they make the difficult trip back home and don't return for several weeks as they enjoy the company of friends and relatives.

As China has become more prosperous, and especially this year, workers have begun to leave for home much earlier then in years past. The reason for this is the relative prosperity in China.

Factory workers no longer are living day to day and when the weather turns cold in early January, they are leaving for the warmth of their fireplace at home with family savings accumulated from two income sources, prosperous children sending money back home, etc.

What this means for you is a more difficult production environment. We have taken steps to plan your production carefully to ensure timely delivery, however please understand that the situation is becoming more difficult: lack of workers, exceptionally poor weather, the Olympics (factories will begin to produce European orders immediately following Chinese New Year in anticipation that shipping will cease during three months of the Olympics), and other factors are combining to make spring production more difficult then usual. Rest assured we have taken steps to manage these difficulties.

I will end this update on a positive note and wish everyone a prosperous and healthy Lunar New Year.

Please see attached some photos of production from this month.

All the best to you and your families,

Matt Palaszynski
Dominator Fireworks, Liuyang, China

Making Fireworks with No Heat

Consumer Fireworks Making In January

What this means to Skylighter’s fireworks makers and buyers

Matt ain’t just awhistlin’ Dixie. The front page story in the Washington Post today reports that hundreds of thousands of people are stuck in railroad stations throughout central China.

We have a number of new products coming in our next container from Matt. But between the weather and the normal two-week holiday for Chinese New Year, it looks like it’ll be arriving later than we originally planned. The wait will be worth it. There are a couple of surprises in that shipment that most of you have never seen before. Stay tuned. Holler if you have any questions. And start making those July 4th fireworks!

How Particle Size & Shape Is Defined

2007-11-21T04:21:34-08:00

You will often see chemicals in fireworks formulas that look like these:

Aluminum, atomized, 22 micron
Aluminum, -325 mesh
Aluminum, -325 mesh, spherical, 22 micron

Do you really know what those particle sizes really mean? What is really being described? When they say "-325 mesh" and "22 micron", what's the difference? And why does it matter to you?

Well it can definitely help you to know how the particle "size" ratings get assigned to metal powders. Most of the size ratings come directly from the wholesaler or manufacturer. But every so often we buy surplus materials which may not come with any additional information about the manufacturer, the size or shape of the powder. Recently, we received a surplus lot of magnesium powder, including several drums with almost no information available from the seller. Before we can sell it to you, we need to be able to tell you what it is, so you can figure out if it suits your purposes.

The first step in the identification process is a visual inspection. You may be surprised how much you can tell about a sample just by looking at it. By observing the flow characteristics of a powder, and how it feels between your fingers, you can approximate particle size and shape. If you have experience with metal powders, for instance, you can often tell if a sample is granular (rough feeling), or atomized (round particles, feels smooth, pours and flows quickly and smoothly). If you cannot feel any particles between your fingers, you can assume the powder is probably finer than 200 mesh, or even less than 325 mesh (written as "-325 mesh.")

The next step is to verify those assumptions though quantitative and qualitative testing.

To determine if a material is appropriate to be used in a given formula you'll need to know the particle's shape (morphology), size, and distribution (granulometry). Shape is easily determined under a microscope and classified as atomized (spherical or spheroidal), granular, or flake.

Particle size is reported in one of two ways: either by mesh size (large and medium particles, generally larger than 325 mesh) or by microns (very small particles).

Why use two measurements?

US mesh size describes the number of openings per inch in a screen. So if a material is listed as -60 mesh it will all pass though a 60 mesh screen (the minus sign in front of the 60 means that all particles are smaller then 60 mesh). Conversely, if the material is described as +60 mesh, it would mean that all particles would be retained on a 60 mesh screen and are therefore larger than 60 mesh.

But mesh sizes can only go so far. After a point the individual wires that make up the screen are so close together it is no longer practical to measure using screens. In practice, particles smaller than 325 mesh are usually described in microns. A micron is one thousandth of a millimeter, or one millionth of a meter. The unaided human eye can see particles of about 40 microns. Smaller than that, you need magnification.

There is no truly accurate conversion from mesh size to microns, because the wire thicknesses in screens vary all over the place. But approximate conversion tables are commonly used anyway. (In the table below, screen sizes of smaller than 600 mesh are shown, even though they don't exist in practice.)

U.S. MESH		MICRONS
10		2000
20		841
40		400
60		250
80		177
100		149
200		74
325		44
400		37
625		20
1250		10
2500		5

More detailed conversion charts are available at:
http://www.skylighter.com/fireworks/help/
Mesh_to_Micron_Conversion_Chart.asp

"Mass fraction analysis" is used to determine large-to-medium size particle distribution in a sample. The powder is sifted through a set of nesting screens, each with progressively smaller openings (higher mesh numbers). By measuring the percent of material that remains on each screen, we can classify a material by its size distribution.

If you were to sift Skylighter's #CH2080 Magnesium-Aluminum (described as 180-325 mesh) through a stack of 180 mesh, 200 mesh, and 325 mesh screens, a mass fraction analysis yields a particle size range that looks like this:

+180 mesh	26%
180-200 mesh	31%
200-325 mesh	21%
-325 mesh	22%

If the 180 mesh size was critical to your firework formula, you can interpret this to mean that 26% would remain on the 180 mesh screen (larger then 180 mesh) and 74% would pass through it (be smaller than 180 mesh).

Mass fraction by sieve analysis is a very helpful method of classifying coarse-to-medium particles, but what about the really small stuff?

When the average particle size is around 50 microns, sieve analysis is no longer practical, and doesn't adequately describe the particle sizes. Several methods are commonly used to measure really fine stuff: gravitational sedimentation, laser light diffraction, optical light microscopes, scanning electron microscopes (SEM) and transmission electron microscopes (TEM). The most accessible method to an amateur is an optical light microscope.

So how is a particle measured with a microscope? Do you need some kind of tiny ruler? As funny as that might sound, that's exactly how it's done. The microscope can be fitted with a gizmo called a reticule micrometer. After it is calibrated, it can be used to measure the size of individual particles in a powder sample right down to 1 micron.

But just because you can measure it doesn't mean it's a simple task.

Sure, measuring spherical material is fairly straightforward. After all, you're really just measuring the diameter of little balls. But what about flake, granular, and spheroidal samples? Digital imaging and software can drastically decrease the time needed to perform measurements and reduce error rates. But it appears that most if not all of the automated equipment measures any particle shape as if it is spherical. Because of this, there is not really a standard method for assigning a particle size.

Selecting the method seems to be based mostly on what you'd like your results to state. Below is an imaginary particle and three circles representing different measurement methodologies.

In the first example the measurement is across the smallest dimension of the particle. This method might be used to describe the particle in terms of its reactivity by describing the particle in the smallest possible size. Method B might be used conversely—to describe the particle's largest dimension. Arguably the most accurate methodology would be using example C, where an average size is calculated.

No matter what method is used, the results would normally be presented to you, the buyer, as an average size (3 micron), a particle range (3 to 15 micron) or a frequency distribution (30% <5 micron, 10% 5-10 micron, 60% 10-15 micron), or some variation thereof.

So why does particle size or shape matter?

Many amateur fireworks makers only consider particle shape and size when a formula calls for a specific material. Even fewer consider particle size distributions. The shape and size of a particle has a huge impact on its reactivity. Flake particles have a large surface area that can be in contact with an oxidizer when compared with a spherical particle. Granular particles often have sharp edges that can ignite more easily than the smooth, round edges of an atomized powder.

Selecting powder with a different particle size or shape can create a wide variety of changes in the pyrotechnic effect, from hang time of a spark to delay of strobing. Even controlling the burn time can be accomplished by altering the particle size and shape.

Look what happens when we change particles in a real example.

The glitter formula below calls for -325 mesh spherical aluminum. Skylighter sells 3 aluminums that are -325 mesh spherical. One is further described as 5 micron (CH0100), one is 12 micron (CH0103) and another is 22 micron (CH0105).

D1 Glitter Formula
Chemical	Percent
Potassium Nitrate	53%
Sulfur	18%
Charcoal (airfloat)	11%
Aluminum (-325 mesh, spherical)	7%
Sodium Bicarbonate	7%
Dextrin	4%

Using the 5 micron aluminum did not produce a usable glitter. Instead it produced a bright star with an unattractive, dense, short-lived flitter-like tail. This aluminum was simply too reactive and started burning both in the flame envelope as well as after, creating poorly defined flashes.

The 12 micron aluminum produced a wonderfully dense, but short tail of fairly evenly-spaced flashes. Because the particle size distribution was within a fairly small range (mostly 6-18 microns), the glitter effect appeared fairly closely behind the star.

The 22 micron produced the best effect of all, creating a long tail that maintained good distribution of flashes over its entire length (with a few long delay pops). The 22 micron contains particles over a very wide range with most particles appearing between 5 to 38 micron.

It is clear from the results of the test above that tracking the average particle size and shape may not be enough to reproduce a specific effect, tracking the particle size distribution (if you know it) may also be worth noting in your formula book.

Brian Paonessa
Skylighter, Inc.

For more information see:

Mesh Sizes and Microns
Skylighter Fireworks Tips
November 26, 2002 -- Issue #44
http://www.skylighter.com/skylighter_info_pages/article.asp?Item=47#mesh

Metal Particle Shapes: What They Mean

Skylighter Fireworks Tips Newsletter
December 2, 2005 -- Issue #68
http://www.skylighter.com/skylighter_info_pages/article.asp?Item=78#particle

HOW TO MAKE GO GETTER SHELLS

2007-10-11T08:08:56-07:00

"Go Getters" are an animated type of star, usually seen in aerial shells, sometimes in mines. Go Getters appear to "swim" all over the sky. The animated effect is similar to flying fish fuse, but much larger and brighter. Go Getters are the most consistent crowd pleaser of any aerial effect I have ever seen.

As far as we know they were invented in the US by amateur fireworks makers in the early 1980's (if anyone knows otherwise, please correct me).

They were first described by Troy Fish in Pyrotechnica VII in 1981. In 1989 Dave Johnson published a booklet called "Go Getters," which further developed this particular effect. Joel Baechle's 1989 book, Pyrocolor Harmony, contained a reference to a star formula which could make a good Go Getter. Up to that point, most, if not all Go Getters used magnesium as the fuel.

This was the base of information that existed out there in the universe when John Driver decided to make Go Getters. I first saw 6-inch blue, Go Getter shells that John had made in 1995 or 96 at a Florida Pyrotechnic Arts Guild (FPAG) event, and instantly fell in love with them. John first published his findings in the FPAG newsletter, The FirstFire, and went to one of his seminars on making them. Later a revision of the article appeared in American Fireworks News and Best of AFN IV.

John went on to commercially manufacture Go Getter shells and inserts for a few years. He developed an array of colors and added metal spark trails to some of his shells. John and his long-suffering wife, Karin, drove all the way up from Florida to my place in Virginia for my Fourth of July party the year the article below was written. The Go Getter shells he brought were THE hit of the party. I still hear people talking about them. He no longer manufactures his spectacular shells, but you can definitely do it yourself.

John's main contribution to the refinement of the Go Getter effect was his adoption of atomized aluminum in place of the magnesium formulas originally prescribed by Fish and Johnson. Utilizing aluminum increased manufacturing safety and reduced costs. John's technique of using ball shells, different from traditional canister shell techniques, works very well and is much faster. You can use either plastic or paper shells. (See my notes at the end of the article for a bit more information on shell construction and fusing.) He also greatly enhanced the range of Go Getter colors and spark trails. Go Getters of all colors are now frequently seen in imported shells from China and Europe, just another example of the R&D contributions of American amateur fireworks makers to the craft of fireworks. Thank you, John, for all the work you did in furthering the development of these effects and for so generously sharing your work with us.

The article below has been modified by me only slightly by removing the table of contents.

-- Harry Gilliam

AMMONIUM PERCHLORATE/ALUMINUM GO GETTERS

(Revised 6/97)
By: John W. Driver

WARNING: THIS PAPER CONTAINS DESCRIPTIONS OF PROCEDURES WHICH SHOULD ONLY BE ATTEMPTED BY PERSONS POSSESSING AN ADEQUATE UNDERSTANDING OF THE CHEMICAL AND PYROTECHNIC PROCESSES INVOLVED AND WORKING AT AN ADEQUATELY EQUIPPED, LICENSED LOCATION USING ALL APPLICABLE SAFETY PRECAUTIONS.

Introduction and Original Formula

It all started several years ago when I watched a video of a PGI Convention. I observed a new-to-me effect; it looked like the stars were "swimming." After cleaning my glasses and viewing it again, sure enough, self-propelled stars. I already had Troy Fish's article entitled "Green and Other Colored Flame Metal Fuel Compositions Using Parlon" published in Pyrotechnica VII but didn't make the connection. It all became crystal clear after obtaining a copy of Dave Johnson's book, "Go Getters." Well, for one reason or another, the idea somehow got shuffled to the dark reaches of my mind. Although it did resurface from time to time, the final catalyst didn't come until the 1994 convention in Pennsylvania. I witnessed some Go Getter shells in the opening display by the CPA and particularly liked the blue ones. Next came the Go Getter seminar by Dave Johnson and Mark Raitzer, which explained how to make the little critters. Unfortunately, the seminar only presented the same three colors that had been listed in Johnson's book, namely red, green and yellow. All utilized magnesium as the metal fuel. Since I really like the color blue, the hunt was on. Inquires of several fellow pyros resulted in no answers for blue Go Getters. The puzzle finally started to fall into place following a perusal of Joel Baechle's "Pyrocolor Harmony." Right there on page 34 was an ammonium perchlorate formula for violet with an interesting footnote stating "The violet with 10% aluminum and no hexamine is an excellent 'go getter' composition." The original violet formula is as follows:

ORIGINAL FORMULA

Ammonium Perchlorate	50%	Add to cart
Copper Oxychloride	15	Add to cart
Aluminum, fine atomized	7	Add to cart
Hexamine	3	Add to cart
Rosin or Vinsol	5	Add to cart
Parlon	20	Add to cart

Having neither rosin or vinsol, I substituted saran resin (I figured a little more chlorine donor couldn't hurt). Also, for the atomized aluminum, I used 325 mesh, 30 micron, spherical (KSI now Skylighter #007) aluminum. While this revised formula worked nicely in initial tests, I soon started observing bubbling and foaming in the tubes about one hour after they had been poured. In most of the tubes the fuses disappeared completely, as they sank out of sight to the bottom of the tubes due to the agitation provided by the bubbling. The foaming was probably caused by the formation of acetone acids which reacted with the aluminum. In any case, the Go Getters were useless since most of the fuses had disappeared and I didn't like the looks of them anyway.

In desperation, I tried something that shouldn't have worked quite as well color wise as the oxychloride. By substituting copper carbonate for the copper oxychloride, the foaming stopped and, judging by the comments I received at the PGI convention, the effect was quite well received. The final formula is presented below, along with a formula for orange Go Getters. If you want to shift the color more into the "pumpkin" range, eliminate the ultramarine and increase the calcium carbonate to 15%.

BLUE & ORANGE ALUMINUM GO GETTERS FORMULA

	Blue	Orange
Ammonium Perchlorate	50%	50%	Add to cart
Copper Carbonate	15		Add to cart
Calcium Carbonate		14	Add to cart
Aluminum (325 m, 30 mic.)	10	10	Add to cart
Saran Resin	5	5	Add to cart
Cryolite		1	Add to cart
Parlon	20	20	Add to cart

All chemicals are run through a mixing screen a few times and, with the aid of a funnel, are poured into an acetone proof plastic (I use an empty mustard squeeze-type bottle made of LDPE (low density polyethylene)). If you do not have access to LDPE containers, you must experiment to find a flexible plastic material that is not affected by acetone. I find that, except for occasionally plugging up, the squeeze-type container works very well and gives more control over the flow of material than pouring from a plastic drink cup. Dave Johnson's book covers the construction of Go Getters in great detail, so I will only point out the highlights and differences.

The Tube

I use a standard 9/16" ID. x 1 1/2" long spiral-wound, machine-made tube with a 1/16" wall thickness and standard 9/16" end plug. The end plug does not need to be glued in as the parlon, once it sets up, is quite hard and will not blow the plug until the Go Getter is almost done burning, if at all. The tubes are then bundled into a convenient size package (I use bundles of nineteen) with rubber bands and set on plastic film (Saran Wrap), ready for filling. While Go Getters made with these tubes go quite nicely, the tubes are still relatively heavy. If you have the inclination, you might want to try hand-rolling some tubes from Kraft paper with a thinner wall to see if they fly better. Go Getters are end burners, so you should not have to worry about blowing out the tube.

The Solvent

A 90:10 mixture of dry acetone:xylene is used as the solvent. Both acetone and xylene are hygroscopic (absorb water) so it is important to use dry material. Fresh solvent is best, but if you have any doubts about the dryness, the mix may be dried in the following manner. First, the desired quantity of solvent mix is prepared. Then a small quantity (an ounce or so) of drying agent (I use calcium chloride or "Damp Rid^TM" in Florida) is placed in an acetone proof plastic container (plastic two liter soda bottle), the solvent is added, the container is capped and shaken to allow the drying agent to absorb the water. CAUTION: be sure to release the pressure in the container by loosening the cap/lid from time to time. Only a brief time is needed to absorb the water and then the mix is allowed to settle for a few minutes. Lastly, the mix is filtered to remove any solids by pouring it through a double layer of coffee filters and stored in an air/moisture proof plastic container and the drying agent is discarded (it's cheap). It is a good idea to dry only as much acetone as is needed for the batch of Go Getters you are making.

CAUTION: acetone evaporates very quickly, the vapors are heavier than air and extremely flammable. Good ventilation and no sparks are a must.

The acetone/xylene solvent mix is added to the composition in the squeeze bottle at the rate of 35-45% by weight. Some experimentation may be necessary to get the proper viscosity of the mix with your chemicals. The correct consistency is somewhere around a slightly thickened pancake batter (depends on your recipe). After placing the top on the squeeze bottle, squeeze out about 25% of the air (to allow for expansion of the acetone vapor), hold your gloved finger over the spout and shake vigorously for two to three minutes or until everything is thoroughly blended. Depending on the size of the batch you are pouring, you might want to give the bottle a good shaking every once in a while just to keep everything in suspension (don't forget to squeeze some air out first). The tubes are then filled to the brim, ready for insertion of the fuse. It is a good idea to keep a toothpick handy to unplug the nozzle and some paper towels to wipe the nozzle and your hands.

The Fuse (The Secret)

Black match or any other potassium nitrate containing fuse probably should not be able to be used with aluminum Go Getters like it can with the magnesium varieties. This is because of the ammonium perchlorate and potassium nitrate reacting to form the very hygroscopic ammonium nitrate, which may result in a wet interface between the fuse and composition. The trick is to use Thermolite. The Thermolite will not react with the composition and provides a nice hot flame to light the Go Getters. Cut (carefully) the Thermolite in about 1 ¼ inch pieces, remove as much of the fabric-wound outer layer as you can, bend the fuse into a narrow "U" shape and insert it into the Go Getters, "U" end first, about half way, and lay them over against the side of the tube. Make sure you prepare enough fuses to complete the job before you mix the slurry. Once you pour the Go Getters, the stuff sets up rather quickly. After the fuse is inserted, set them aside to dry on a piece of plastic wrap until no odor of acetone is detected (about 3-4 days). As the Go Getters dry, they will shrink back into the tube a little because 1/3 of the slurry, by weight, evaporates.

By having two ends of the fuse exposed to the expanding flame front within the shell, ignition of the Go Getters is improved and more initial thrust is generated due to the two points of ignition.

Construction of a Six-Inch Round Go Getter Shell

A round Go Getter shell is constructed much like any other ball shell of comparable size with a few minor differences. The time fuse is cut to allow a delay of about 4 seconds between cross matching. A fuse extender made from three turns of 30 Lb. Kraft paper is rolled on a suitable former and only pasted on the last 1/4" or so of the trailing edge, just enough to keep the tube from un-rolling. The tube is then slipped over the cross-matched end of the time fuse and securely taped in place (remember, at this time you only cross-match the end of the fuse that goes inside the shell). The fuse is glued into the hemisphere and the fuse extender is cut off so that it just reaches the center of the shell. Two or three pieces of thin black match are inserted into the extender tube to quickly transfer fire from the cross match to the center of the shell (just like building a regular chrysanthemum shell).

The Burst

There are two theories behind the burst charge for Go Getter shells. The first is to use a relatively hard burst to scatter the stars and let them swim back toward each other. Since the stars are placed randomly in the shell, and they are not smart enough to know which way to go, the result is a big boom and Go Getters scattered all over the sky, with the distinct possibility that some of them will be driven toward the ground hard enough that they will not burn out before impacting the earth. My preference is to use a soft break, only strong enough to open the shell and light all of the stars. Meal powder on rice hulls works well for this purpose. A 3:1 or 3.5:1 ratio of meal to hulls works very well. Remember, they are self-propelled stars and don't need to be blown all over the place with your favorite "atomic" flash burst.

Putting It All Together

Two pieces of tissue paper are cut of sufficient size to line the shell hemispheres with enough left over to fold across the top of each shell half to hold the contents in the halves while assembling the shell. A hole is pierced in the center of one piece of tissue and the tissue is inserted over the time fuse and smoothed out against the inner wall of the hemisphere. The second piece of tissue is placed in the other half in a similar manner except for the hole for the time fuse. The Go Getters are then placed against the inner wall of the shell about half way up the wall. Care must be exercised not to obscure any of the fuses. Burst is now poured in to fill all of the crevices between the Go Getters. At this point, just enough burst is used to fill the crevices and leave a thin layer over the already placed stars. Stars and burst are added in alternating layers until the hemisphere is full. Remember to keep forcing burst into the crevices between the Go Getters as this is the only way to ensure shell integrity. The extra tissue that has been hanging over the edge of the shell and getting in the way is now folded toward the center of the shell, secured with a couple of pieces of masking tape. The other shell half is finished in the same manner and the two halves are joined using your favorite shell glue.

As was discussed earlier, you do not need a hard break for Go Getter shells. Consequently, you do not need to paste endless layers of paper on the shells. Four to six layers of 60 lb. Kraft paper will suffice. After pasting, the shell is finished in the normal manner with the final cross match, lift and leader. Good luck and SAFE SHOOTING!

MORE ON COLORED GO GETTERS

Subsequent to writing the original article, I have done some additional experimentation as explained below.

Colors and Catalysts

I didn't realize when I first started making the blue Go Getters that copper acted as a catalyst to increase the burning speed of the composition to make a more lively star. It is therefore quite easy to shift the color toward either purple or lavender by substituting the proper amount of strontium carbonate for some of the copper carbonate to achieve the desired color.

Other colors require a different approach since copper compounds are out of the question due to the blue tint imparted by them. The answer to this quandary may be found with the High Power Rocketry people. More specifically, an article in the Journal of Pyrotechnics # 3 entitled "Ammonium Perchlorate Composite Basics" which discusses, among other things, burn rate modifiers which may be used to control the burning speed of ammonium perchlorate propellants (remember, these Go Getters are baby rockets). Due to time constraints, little research has been done by this author on the suitability of these catalysts, but red iron oxide seems like a likely candidate.

Fuse Alternatives

While Thermolite makes an excellent fuse for Go Getters, its limited availability and high cost discourage its use in any but the smallest of projects. The most promising solution is to use an alternate form of fuse. My first thought was to use an H-3 based fuse (potassium chlorate and air float charcoal), but this is not a viable alternative due to the double decomposition reaction between ammonium perchlorate and potassium chlorate resulting in the formation of the rather sensitive ammonium chlorate (Lin Collins, private communication, September 1995). The next logical choice would then be match based on KP burst (75% potassium perchlorate, 15% air float charcoal and 10% sulfur with 5% additional dextrin). Because the perchlorate isn't particularly soluble in water, you end up with a slurry which must be stirred from time to time while the match is being made. Five strands of single ply cotton string works well for this purpose (you want a fairly small diameter match, like the black match used for cross matching). The slurry must be thoroughly worked into the string before it is drawn through the sizing orifice. When the KP match is dry, cut it into lengths of approximately 1 1/4" or so and insert them about halfway into the filled tubes as you would with Thermolite.

The final step is to prime the fuses to insure complete ignition. For this purpose, the Go Getter (fuse end down) is dipped in a N/C lacquer solution and then dusted with meal powder (home made meal is entirely adequate). Since no moisture is involved, there is no worry of the ammonium perchlorate/potassium nitrate double decomposition reaction occurring.

References:
Johnson, D. S. 1989. Go Getters.
Fish, T. 1981. Green and Other Colored Flame Metal Fuel Compositions using Parlon.
Issue VII, Pyrotechnica: Occasional Papers in Pyrotechnics, Austin, Texas.
Sobczak, R.R. 1996. Ammonium Perchlorate Composite Basics. Issue no. 3, Journal
of Pyrotechnics, Whitewater, Colorado.
Baechle, J. H. 1989. Pyrocolor Harmony, A Designers Guide.

Notes from Harry Gilliam:

The ammonium perchlorate is the 200 micron variety
The uncoated atomized aluminum should be -325 mesh, average particle size 12-32 micron.
Thermolite is hard to get but worth it if you can lay your hands on it. The last place I saw it for sale was from Coonie Coyle: Coonie's Explosives & Powder, 512 East Lea Street, Hobbs, NM 88240, (505) 393-0166
Mix and dry the solvents EXACTLY as John has recommended. Do not skip the drying step. If you have any doubt that your solvents may have water in them, dry them before using. Removing the water from this composition is necessary for your safety. The presence of water in this composition could cause the mixture to heat up and spontaneously ignite. Removing the water will also help the Go Getters to dry more quickly.
I suspect you can substitute one of our flying fish fuses for a ready-made fuse, if you do not have Thermolite or don't want to make KP fuse. Try silver or crackling flying fish. I have not tried this, so consider it experimental.
For a time, John was using plastic ball shells, pasted with several layers of paper. My guess is that you can use plastic shells, glued well, and then add 2-3 "X's" of fiberglass reinforced strapping tape across the equator of each shell. These shells do not have to break hard. So the extra compression added by the layers of paper may not be absolutely necessary.
Acetone is both flammable and poisonous. Either use it outdoors or in a very well ventilated area. The acetone in your Go Getter goo will dry out quickly while you're squirting the stars. Keep some more solvent on hand to add to the mix so that you can thin it as need.

How to Make Strontium Nitrate Sparklers

2007-10-02T06:05:31-07:00

The very popular fireworks making book, Introductory Practical Pyrotechnics provides a neat project for making sparklers. Problem is, we can't ship barium nitrate. What to do? Here's a sparkler project formulae that doesn't need either barium nitrate or potassium perchlorate. Thanks to one of our readers, who wishes to remain unanimous.

A Sparkler Made with Strontium Nitrate

Strontium Nitrate Steel Sparklers

Component:	Parts:
Strontium nitrate (CH5543)	200 grams
Sparkler-grade (or any other) steel powder (CH8300)	120 grams
Aluminum, bright flake, -325 mesh (CH0174)	32 grams
Airfloat Charcoal (CH8068)	2 grams
Boric Acid (CH8042)	6 grams
Dextrin (CH8107)	40 grams
+90 ml 25% aqueous ethanol (alcohol) solution

Grind unground components (if any) separately. Mix together all components except dextrin. Add 25 ml of 25% aqueous ethanol (25% alcohol, 75% water) to dextrin and stir until it becomes a paste. Break up or discard any large clumps that form. Add paste to dry components and stir. Add 65 ml more ethanol solution, with stirring. Dump mixture into 41 mm OD x 12" long test tube (or pipe, whatever). The wet sparkler composition should be 7" to 8" deep.

Dip sparkler sticks (or wire/whatever) into mix and let dry 24 hours. Then apply 2 more coats in same manner. If needed, add about 5 ml ethanol solution to re-wet mix. Let dry 24-48 hours.

The slag from the sparkler dip is fun to let dry in a pile and light on fire on the ground, too.

Notes:

You may have to adjust the volume of ethanol solution to make the consistency right; it seems to be slightly more or less every time I do it.

Sparklers may be difficult to light. Propane torches or those butane cigarette lighters held on for a minute tend to do well. They can also be lit off each other. I sometimes use a prime just for the tip that uses perchlorate [or try a black powder/dextrin slurry].

When the slag dries, you can notice rust from the steel. This may indicate that coating the steel with linseed oil first may be the way to go, though I haven't ever had any problems with it. These were made in the Missouri summer, so they had plenty of humidity around.

The paste can come out a bit clumpy. Larger batches will even out the coatings a bit. I haven't tried, but thorough mechanical mixing once slurried would probably help, too. It doesn't affect the sparklers' burning at all.

I have enclosed a picture of one of these sparklers burning. They burn very nicely, actually a little better than the commercial grade sparklers that one can buy, and they last longer, too. I think this is from a chemistry demo we did in a lab, which is why it's indoors. Usually I burn them outdoors. Note the safety goggles on the user.

The formula isn't mine originally--I just modified it slightly. Hopefully this will give you something to tell the people that whine they can't make sparklers without perchlorates. I've actually tried several formulations, including those with perchlorates, and the ones with perchlorates burn too fast, too erratically, and a little too energetically for using as a full coating.

I have found one or two of these perchlorate formulae are useful though, that I will use to coat the tips of the sparklers with just to get them going, since they are easier to light and burn hot enough to get it started.

Making colored smoke using Skylighter's Smoke Mix Kit

2007-08-28T05:52:47-07:00

You should use protective gloves when making colored smokes, and cover all surfaces with newspaper or some other covering to be thrown away later. Working with smoke mix can be very messy no matter how careful you are. The dyes will stain anything they come in contact with, so lay down newspaper over your work surfaces and protect your hands with rubber gloves.

Skylighter's smoke kit is already pre-measured and ready to go. If you mix all of the dye mix and oxidizer provided in your kit, you'll end up with

about 1.25 lbs. of finished smoke composition. Just mix the smoke mix with the potassium chlorate oxidizer.

Mix the chemicals

An easy method for mixing small amounts of insensitive composition is called "bag milling."

Use a plastic bag big enough so it is not more than half full after adding all the chemicals. If you are going to mix the whole kit at one time, dump all of the smoke mix and the potassium chlorate oxidizer into the bag. Use your fingers to break up any lumps while mixing the composition. Once mixed, the material should be a consistent color and have no sign of any lumps. If you're not sure if it's mixed enough, keep mixing. The more you mix, the better the generated smoke will be.

If you want to mix less than the contents of the whole kit, the proportions should be 27% potassium chlorate and 73% smoke mix by weight. You must use an accurate gram scale to weigh them.

Once mixed, your smoke is basically ready to go. It will actually burn just fine in the open without any containment. This is a good way to test how well it's mixed. The composition should light easily with a match or fuse, and burn with little or no visible flame. But to use your smoke for anything practical, you’ll need to build a container for it. In the instructions that follow, that canister will be a paper tube with cardboard end plugs.

Build a smoke canister

Place a small bead of white (Elmer's or carpenter's) glue around the inside lip of the paper tube

and press the plug into place. Using your fingertips, seat the plug flush with the end of the tube. You can insert the plug either way into the tube. Once this is done, set the tube aside to dry for several hours.

Make a fuse cap

Holding a paper plug between your fingers, poke a hole large enough to slide a length of visco fuse through. The fuse should be cut long enough so that you can push the fuse through the

cap and all the way to the bottom plug. Set the fuse cap assembly aside for now.

Load smoke composition and cap the tube

Using a small scoop, loosely fill the tube with smoke composition up to about one-quarter inch from the top. There is no need to compact the smoke composition. Keeping it loose and fluffy will increase the burn rate and also improve the color of the smoke produced.

In the same way that you glued the end plug in, place a small bead of glue around the inner lip of the canister and slide the fused plug in place. Once done set the canister aside to dry for a couple of hours until the glue is dry.

Once it's dry, just light the fuse and let her smoke!

Enjoy.

Suggestions & troubleshooting:

Q: After lighting, the bottom or top plug pops out.
A: Be sure your plugs are thoroughly glued in and that the glue is dry. If they still pop out, increase the size of the smoke vent. Bigger smoke devices need larger orifices for smoke to vent. Try punching several holes in the top plug.

Q: How can I make the smoke comp burn faster?
A: In some instances you may want to generate a lot of smoke very quickly. The best method is to add 5% dextrin and dampen the mixture slightly until it just holds it shape when you squeeze it in your hand. If water comes out when you squeeze it, it's too wet. Then press the dampened composition though a 10-20 mesh screen to granulate it. Once dry, load the granules loosely in a smoke canister.

Q: The smoke is vivid in color for awhile, but then fades to gray.
A: The ash is trapping the sublimed dye. You can either make a smaller or shorter device or mix 15% fine sawdust (-40+60 mesh) into the smoke mix. Either should resolve the problem.

Make a Festival Ball Fiberglass Mortar Rack

2007-06-06T15:09:00-07:00

The Mighty Fourth is closing on us and you haven't even begun designing your fireworks display, right? "I've got plenty of time," you say. And every year, you think to yourself, "Man! I need to buy more mortar racks." And every year you wait 'til the eleventh hour, and end up either reloading your mortars during the show, or worse, using the cheap cardboard mortar tubes that come with your reloadable shells! Well, why not invest an hour or two right now to get ready? Here's a nice little "do it yourself project" that you can finish in about an hour if you have everything ready to go. This year you can get started early and paint the sky with festival balls the night of the Mighty Fourth of July!

20 shot, festival ball, fiberglass mortar rack

Materials needed:

Baseboard: 1 pc. 1 x 5 plank, 23 inches long.
End boards: 2 pcs. 1 x 5 planks, 11 inches long
Center rails: 2 pcs. 1 x 2 furring strips, 21-1/2 inches long
Side rails: 4 pcs. 3/8 inch thick plywood, cut
2-1/2 x 32 inches
20 fiberglass festival ball mortar tubes (#PL3182)
46 pcs. 1-1/2 inch drywall screws

Tools Needed:

Wood saw (table-saw or chop saw if you cut your own wood pieces)

Assembly:

Figure A: Use mortar tubes to support
1 x 2 furring strip center rails while attaching to base.

Attach the end boards. Screw the two 5 x 11 end boards to the outside edges of the 5 x 23 base board. (Set your screws through the bottom of the base board into the each end board--see figure A and B.)

Figure B: Screw placement for 1 x 2
center rail

Next, install the center rails. Place one of the 21.5 inch furring strips on its edge, directly in the center of this base (see figure A). It's helpful to lay the base on its side and use several tubes as spacers to support this bottom center rail. Then attach the rail by screwing through the ends and bottom, as shown in figure B. Attach the top center rail frame as shown in figure A, screwing into it from the end boards.

Figure C: Mortar tubes should fit flush
with each side of the base board in the unfinished frame

Check your spacing. You should now be able to place mortar tubes on either side of the center rails with the edges of the mortar tubes flush with each edge of the base board as shown in figure C.

Figure D: Placement of lower side rail

Attach upper and lower side rails. Stand your mortar rack up on its base (see figure C). Screw one of the 2-1/2 x 32 plywood side rails to the base and end boards as in figure D. Once the lower side rail is screwed in place, attach one side of the upper side rail flush with the top corner of one end board as shown in figure E. If the rack is not completely square, pull in the opposite end flush with the side rail to square the sides--attach that end. Flip your mortar rack and attach side rails to the other side as well.

Figure E: Plywood side rails
screw attachment

Test fit the tubes in the finished frame. They should fit snugly, but you should be able to remove them for cleaning later on.

Safety:

The mortar rack you just finished may feel stable on a perfectly level, flat surface. But it will need to be supported when it is in use. This can be done by adding support legs or braces to the ends of the mortar rack, or staking the mortar rack in place, or screwing several mortar racks together to form a larger footprint. It's not important how you secure your mortar racks, just that you do secure them.

The orientation of your mortar rack to the audience is critical to their safety. If a shell explodes inside a mortar tube, it will tend to blow out the weakest part of the mortar rack. The weakest part of this rack are the plywood side rails. And if the side rails are blown out, this could mortar tubes to fall over. So, it is important to orient your mortar rack so that any falling tubes would be aimed away from your audience. This prevents mortar shells from being fired directly into the audience, which can be very dangerous. Therefore, when you set up your display, orient your mortar rack so one end board is facing the crowd. See figure F below.

Figure F: Safest mortar rack orientation toward audience--perpendicular to them. In the
event of a failure the mortar tubes will fall parallel to your audience. Note stabilizers
on each end and stakes holding the mortar rack in place.

Connecting Electric Matches to Visco (Cannon) Fuse

2007-06-05T14:24:12-07:00

About this time of year we get lots of questions about attaching electric matches to consumer fireworks. That's because more and more people are using electrical firing systems to fire their 4th of July consumer fireworks shows, even at home. Here’s how to do it.

The Problem:
Electric matches made using Skylighter’s Electric Match Dip Kit (GN5050) and Electric Match Blanks (GN5040) put out a good amount of fire and can directly light visco fuse when connected end-to-end. Visco fuse is the green fuse used in most consumer fireworks (it is also called cannon fuse). But just taping the electric match to the visco fuse is not 100% reliable, so the connection technique you use is critical. Here's a little trick that works quite well for me when connecting electric matches to visco fuse and has given me 100% ignition so far.

Materials needed:

Consumer fireworks
Electric matches ("ematches")
Roll of clear packing tape or masking tape.
Roll of quickmatch (GN3001) or Super-Fast Firecracker Fuse (GN1205)
Razor blade

Assembly:

Cut visco fuse at an angle. Cut the firework's visco fuse on a sharp angle (as seen in figure A). This will expose more of the fuse's black powder core. If your device comes with a long visco fuse attached, you may want to cut it down to about an inch to reduce ignition delay.

Figure A:
Cut visco fuse at an angle

Create a quickmatch sleeve. Using a razor blade, cut a length of quickmatch about 1 inch longer than the fuse supplied with the consumer firework device.

Note: It's best to cut quickmatch with a razor blade or anvil cutters. Quickmatch can ignite from the friction of scissors cutting through it.

Slide quickmatch over device's fuse. Carefully slide the device's fuse into the center of the quickmatch sleeve. Slide the quickmatch sleeve all the way down so it covers the firework’s entire fuse.

Figure B:
Slide quickmatch over fuse

Insert electric match into quickmatch. Outside and away from people, hold the device so it is pointing away from you and any flammable material. Insert an electric match into the open end of the quickmatch to a depth of an inch (as in Figure C). You may need to slide back the electric match's protective plastic cap.

Note: Removing the electric match's protective cap may make inserting the ematch easier, but can cause ignition by friction. Insert the ematch's head slowly and gently.

Figure C:
Insert electric match

Tape quickmatch, and electric match to device. Secure the electric match to the side of the firework with clear packing tape covering both ends of the quickmatch, as in Figure D. Add a couple of extra wraps of tape to secure the electric match in place.

The tape serves two purposes:
1) It confines the burning gasses, increasing the burn rate.
2) It secures the ematch in place.

Tip: If you've never done an electrically fired fireworks display, just imagine people moving about in complete darkness with dozens of wires all around. It's inevitable that if you don’t completely secure each and every electric match someone will trip on "that" wire and pull the electric match free causing a misfire.

Figure D:
Tape electric match in place

How does it work?
When the electric match fires, the ematch sparks for only an instant. If the ematch sparks and fire do not directly hit the visco's black powder core, the electric match may fail to ignite the firework device. The blackmatch inside the quickmatch sleeve prevents this problem by carrying the fire forward, and increasing the amount of fire given to the visco fuse. This ensures that the slightest spark from your electric match will pass fire to the visco. The quickmatch’s outer paper wrap directs the fire downward through the tube like a flamethrower, lighting everything in its path, including the visco.

"But, I live too far away to pick up quickmatch..."
Having quickmatch on hand does make this process faster, but all you need to make this work is blackmatch and a homemade tube to direct the fire. Skylighter's GN1205 is a great source of blackmatch, unless you want to make your own.

What is GN1205, Super-Fast Paper Firecracker Fuse?
Well it's our fastest, shippable fuse. It burns at 1 foot per second! It consists of 3 strands of blackmatch with a light tissue paper wrapping. This tissue paper wrapping gives it a controlled fast burn great for chaining candle batteries, adding leaders to homemade festival balls, even chaining up your finale.

Harvesting blackmatch from GN1205. Gently peel the tissue paper off of the Super-Fast Firecracker Fuse as shown in Figure E.

Figure E:
How to remove blackmatch from Super-Fast Firecracker Fuse

Make a thin walled tube. You'll need a thin walled paper tube to hold the blackmatch, visco and electric match all in place. For this cut a 3 x 3 piece of copy paper, and roll it on a 3/8th inch dowel or anything about that diameter (a Bic pen works well). Use glue or tape to keep it closed.

Insert blackmatch into thin walled tube. Insert 6 strands of blackmatch into a thin walled paper tube (as seen in Figure F). If the blackmatch is long, cut it flush.

Figure F:
Insert blackmatch into tube

Continue by following quickmatch instructions above.

The preceding tip provided by,
Brian P.
Skylighter

Last Minute Tips for Ematch Makers

2007-05-25T17:47:21-07:00

HOMEMADE ELECTRIC MATCHES

This notice is to put you on notice that you should notice that July 4th is coming. Sooner than you think. And we researched this to be sure of what we’re predicting. “As far as we know”… July the 4th has come on the same day, every year, since it was invented by King George II back in 1776. Or was in 1789? Or George W.? Whatever.

Now, I am always asked many times around June 30th how come we A)ran out of a particular item and B)“how come you can’t ship it to me in time?” These are silly questions, silly rabbit. But we still get asked them between June 30th and July 3rd every single year! Hah!

One item that we run out of every year, no matter how many more we buy this year than last year, is kits for making electric matches.

If you want to buy ready-made electric matches in the US, you need an ATF license. And, even if you have the license, they’re still expensive. But if you make your own ematches, no ATF license is required. The fastest way to ematch nirvana is to use our ready-made ematch blanks and dip kits. Then just let ‘em dry, and faster than you can say “pop,” you’re ready to go.

Why dip kits and ematch blanks? Well, primarily because they let you make literally hundreds of ematches in just a couple of hours. You can even do it while you're watching TV. The ematch blanks are really ematch chips with two lead wires already soldered on. The dip kits are exactly the chemicals you need to make 300-500 ematches. They are premeasured, in separate bottles. You just follow the instructions and mix them up in a few minutes. You don't have to order larger quantities of chemicals than you need, which saves you a lot of money in excess chemicals and shipping. And you DO NOT NEED AN ATF LICENSE to buy or make your own ematches. In fact, the ATF has even sent customers to us for these ematch kits! We ran out of ematch blanks twice in the past 12 months. But the new ones are now available on our web site. On the Ignition Supplies page, order

GN5040 Ematch Blanks, 1 Foot Wires $17.94 for 40
GN5050 Ematch Dip Kit $39.95-enough for 300-500 ematches

Each Dip Kit is enough to make 300-500 electric matches. So, be sure you buy enough Ematch Blanks to make as many finished ematches as you think you will need. Procrastinators, do not jump on this stuff, right away. Naw, leave it for the pyros who prepare for the Mighty Fourth in time.

EMATCH MAKING TIPS

• Follow the directions in the dip kits to the letter. They work really well if you do exactly what the instructions say. Don’t try to improve upon them, rush them, or cut corners. You’ll just waste your money, time, and materials.

• Don’t forget to buy Shooting Wire, GN5010, to put lead wires on your ematches of the desired length.

• Homemade ematches are not perfect. Your homemade electric matches will not function 100% of the time—they are not as good as the commercially made, but considerably more expensive electric matches. But you can still make ematches which are reasonably reliable, especially if you test them ahead of time.

• Test your ematches. Commercial continuity testers will frequently generate enough test-current to fire your ematches. Instead, use our special, low-voltage Ematch Tester (GN5005) to make sure your matches are good before you use them.

• Don’t Over Dip. It only takes a very small amount of pyrotechnic composition on just the tips of each ematch to make them work. Keep your pyrogen thinned. Big, fat blobs of pyrotechnic composition are more likely to break off or crack.

• Use your Ematch Dip Kit all in one session. After you mix your dip kit contents, it is best to use it all up in one sitting. Two reasons: First, the stuff will eventually dry up if you try and store it. If it does, it’s then useless and you’ll have to throw away what’s left. The other reason is that the dry, mixed composition can ignite from friction. Friction--like that induced from screwing the bottle cap on and off. So the most cost-efficient thing is to use all of your dip kit up all at one time. This is a 2-4 hour project, but one you can do sitting in front of the television watching “Planet Earth” reruns.

Holler if you have questions. We are sitting here twiddling our collective thumbs, awaiting your bleating cries.

Harry Gilliam
Chief Cook & Bottle Washer