Coil Winding on Cantex 6 inch PVC Electrical Conduit

A first attempt at winding with 3/32" wire

2019-09-30T13:45:00.001-07:00

Before winding, the tube is cleaned and blue painter's tape is applied at one inch intervals around the entire section. A thin coating of DAP Alex Plus acrylic caulk is applied to the spaces between the tape lines and allowed to dry for 24 hours. The caulk strips will hold the wire in place during and after winding.

Here the tape is removed in preparation for winding. The wire transport used in prior projects has been rebuilt using wood instead of plastic parts for weight reduction. The sheave on the headstock has also been replaced with a wooden disk.

This is the test setup for the new drive. The bulky old pulley fixture had no speed control and is replaced by the Harbor Freight variable speed polisher , HF item number 60626. The polishing pad is replaced by a small pulley from a clothes washing machine sized to accommodate the 1/4" drive belt shown here.

The polisher has a speed range pot embedded in the handle

which can be set to any speed the operator likes.

The drive is attached to carton for easy alignment with the drive sheave. It's own weight is enough to provide medium tension on the drive belt.

A door hinge attaches the drive to the carton. Now the optimum location for the drive is set directly

underneath the wood sheave.

The wind at the half way point. The 3/32" wire bites into the acrylic strips for consistent alignment.

The finished piece is 9 feet tall, sports 500 turns of wire, and is even free standing !

Here's a closeup of the finished coil.

A homemade wire guide is shown here. The clear plastic tubing has a 1/8" id and comes from the stem of a bottle of spray cleaner. The yellow base is a shim used to align ceramic parts.

The two are held together with Harbor Freight Super Glue.

As the coil form rotates, the wire is drawn through the tubing and the space between the turns, or pitch, is maintained by the edge of the shim rubbing against the previous turn, held in place by the operator's hands.

The latest version is up and running...

2018-09-02T20:35:00.000-07:00

The .045" stainless steel wire version is finished and set up. The new base section keeps the XLY's flowers out of harm's way.

Have an opinion or observation ? Please let me know. Thanks.

showman_44221@yahoo.com

At the Half Way Point

2018-09-01T02:13:00.002-07:00

The first half of the project is completed. It took about 5 hours to wind at a surface travel speed of 138 inches per minute. DC resistance is measured at 295 Ohms. The wire is 309 stainless, .045" diameter.

The adhesive used on the original job with this Cantex section is still pliable, and will hold the wire in position. The best tool I've found for pruning the coil is the human fingernail. If you have a better idea, please let me know.

Setup Complete

2018-09-01T02:03:00.001-07:00

The new setup includes idle support wheels that float the tube in an X/Y pattern as opposed to the old wheels which simply rotated in one direction. The 6" tube has a tendency to travel in one direction, the the newer idlers minimize the motion.

The brick shown above keeps the main rotation motor stand from moving as coiling progresses. Over three of four hours, the drive will move on it's own enough to require operator intervention if not held in place securely.

The new wire guide is the cartridge from a ballpoint pen. It's ID is .046 - .048 " and it's wall is .024 -.025". It seems to be made of tough material, and it's perfect for closely spaced wire winding. The goal is to stuff 15 turns of wire into 1 inch of coil form. This translates into approximately 1388 feet of wire per half of the dipole antenna using .045" wire.

Beginning a New 6 Inch Project, August 2018

2018-08-28T16:17:00.001-07:00

The wire from the old vertical dipole antenna is stripped off, and the 10' Cantex tube section is ready for a new life.

The support brackets have extra height due to the addition of another carton on each end. The tube is now at eye level for the operator, affording better control and inspection of the winding process.

To accommodate the operator, an extension has been added to the plain end of the tube.

We'll be winding close to the end of the tube, and the idler wheel set has always been in the way.

Adding an 18" extension solves this problem.

The photo on the left shows the 18" piece with an internal alignment mandrel placed on a viewing stand. The arbor is 48 inches long, and fits inside both the extension and the tube. It's made of 2 x 6 scrap lumber, cut into three pieces to form a cross. The wooden assembly is held together by pressure from the extension, and has a sliding fit inside the main tube. For rigidity, the insert should be set at least 2 feet into the main tube. As the main tube rotates, the extension rolls at the same speed and there is no chatter or vibration. Assembly and disassembly are both quick and easy. And the price is right.

Here the extension is attached. The screw that secures the end of the coil wire is close in length to the wall of the tube: about .238".

Connected and Ready to Go !

2018-06-08T18:56:00.000-07:00

The finished part is set up in an out-of-the-way corner so as not to be obtrusive. This is the quintessential all-band ham radio antenna for restricted lot use. The simple neighbors' unwelcome curiosity is kept to a minimum by the low profile, and the XYL can still populate the area with her nefarious green things.

2018-06-08T18:50:00.002-07:00

The tooling is removed and a completed dipole antenna is ready for action. Weight is about 70 pounds, so exercise some caution.

2018-06-08T18:48:00.000-07:00

With any garage project using junk parts, unwanted variations in alignment and fit up make their way to the finished product. The Lash shims, or "Wedges", shown here are indispensable for correcting and fixing minor things that need adjustment. A bag of 50 pieces is available at The Home Depot for around $9.00. A very good deal considering...

www.LASHspacer.com

2018-06-05T14:58:00.000-07:00

Half of the dipole is complete: 53.5" of wind with .062" (1/16") wire. Approximately 742 feet. Measured DC resistance is 58 ohms.

2018-06-04T16:35:00.001-07:00

The head stock and drive motor are lined up and ready for winding. That 14" section from the first slide adds the extra length for winding at the tube base. Now we need the rubber hammer for end-to-end alignment.

2018-06-04T16:21:00.000-07:00

Both ends of the 10' tube section are marked every 60०. These indicate the centers for Dynaflex 230 adhesive strips (6) which will secure the wire windings on the tube. It's available at The Home Depot. Although sold as a window sealant, the all-weather characteristics of the '230 make it ideal for this application. See the manufacturer's web site for usages and safety data; http://www.dap.com/dap-products-ph/dynaflex-230-premium-indooroutdoor-sealant/
Use 3/4 to 1 inch spacing for the sealant strip width. Blue painter's tape is used to set the space. Use your fingers cover the gap with a very thin coating of sealant. Disposable latex gloves come in handy for this job.
Allow the goop to set up for at least 4 hours before removing the tape. These strips will secure the wire in position by forming small landing pads that stay flexible for a long time. And it's inexpensive.

2018-06-04T15:56:00.002-07:00

The new 6" flange is mounted to the original sheave. The 14" tube section on the right will serve as the connector between the head stock and the coil form. It's cut from a junk piece of schedule 80
tube. Normally it would be glued to the flange socket, but not in the case of 6" tubing.

2018-06-04T14:00:00.000-07:00

Both the socket seat and the end insert are coated with automatic transmission fluid. The ATF compound has tremendous film strength, and keeps the insert from seizing in the socket seat for quick disassembly. Final alignment of the fixture involves using a rubber hammer, so glue is ruled out.

2018-06-04T13:30:00.000-07:00

The blue painter's tape shown here defines the channel for the Dab adhesive. Chalk lines are helpful for siting the tape position but are not necessary. The glue is applied by hand for a thin coating along the entire length of the tube. Wait at least three hours before removing the tape. The wire will find a permanent seat on the sealant immediately as winding proceeds.

2018-06-04T13:00:00.000-07:00

The operator's mobile station is in position. The on/off control line is behind the fixture so as not to be run over by the transport wheels. There is no brake on the motor, so rotation will continue for 2 to
3 seconds after the power is turned off. The control switch can be seen just to the left of the wire spool.

2018-05-16T08:18:00.001-07:00

The Ugly Balun is attached to the dipole. It's wound with RG6/U.

The 20 footer goes together

2017-06-28T16:30:00.002-07:00

Monday, June 26, 2017

The new schedule 40, 4 inch, 20 foot section arrives from Mars Electric.

Getting the piece off the truck and carrying it into my garage, I learn one thing immediately;
it's too big for me to handle.

The first thing to do is to trim it down to 15 feet.

The bell end of the tube is resting on the idler roll in the background. The cut end is in the foreground
and will be fitted with a Cantex 4" coupler, P/N 6141632.

The coupler has perfectly trimmed edges and with the face of the headstock fitting the two edges form a channel for the headstock support wheels. Now there is no travel of the tube in the fixture.

Next, the A52EA42 will get all taped up in preparation for applying the Dap Dynaflex 230 (clear)
caulking compound. The blue painter's tape is used to make 3/4" channels every 60 degrees of rotation, or 6 channels, on the entire length of the tube. The Dap material goes on white and is spread on the channels with the fingers to form a thin coating.

When it drys to a clear finish, it's time to peel off the tape.

Four holes are drilled next; two for each half of the dipole. A one inch space is left in the center
for mounting the coaxial cable retaining clamp.

Above, one half of the winding job is complete. The aluminum .062" (1/16") wire goes on smoothly and the Dynaflex 230 holds it in place perfectly. Coiling time for the 82" section is about 3 hours.
The on/off switch is mounted just to the left of the wire spool. There are always frequent starts and stops, and this is a convenient place for the operator. Also notice the glasses on the seat behind the spool. These are 3.5 dioptre in strength, and are necessary to pinpoint the exact location of the wire
and the guide tool.

To end the job, we'll start the second half from the opposite end of the tube, close to the headstock.

Finally, we're done winding, and only the coaxial cable connection remain.

Standing next to the garage, the finished product. The vertical dipole has two coils each 82 inches
long. 779 feet of wire cover each half.

Note !

The XYL's plants must be protected at all costs !

Another approach for wire stability

2016-11-16T06:45:00.001-08:00

Today we'll tackle the problem of coil stability in a new way.

Here is a new 10' section of schedule 40 4" Cantex, ready for cleaning. Scotch-Brite and windshield washer fluid are used to remove small surface nicks and dirt.

The two black plastic brackets holding the tube are called base spacers in Cantex-speak, part number
5355969, and are not very expensive. They come in very handy if you do any work with 4" material.

After cleaning, a protractor is attached to the bell end of the tube.

We'll make hash marks every 60 degrees, for a total of six on the circumference.

The protractor is fastened to the other end of the tube, and six more hash marks are drawn. Now we
have two end points for the next step, snapping a chalk line.

Next, we uses blue painter's tape to make a 1/2 inch channel.

Half of the tape is shown here. We remove the chalk line before putting on the second tape border.

With both tape lines in place, we're ready to apply the wire stabilizer. This is a very thin coating of DAP
Dynaflex 230 caulking compound, purchased from the Home Depot. Please read the instructions on the container. This stuff sticks to PVC and is useful over a wide temperature range. You may want to make a practice run first. Try putting down a bead about 1/10 of an inch in diameter.Then use a latex glove or wrap your index finger in plastic wrap and smooth out the caulk manually. The goal is to make a small adhesive pad for the coiled wire. Give the Dynaflex 5 minutes to set up before removing the tape.

The thin caulk line presents a low profile on the tube. Next, we wind the coil.

Another approach to coil stability.

2015-11-04T19:11:00.000-08:00

The brake on the wire spool hub is set to hand tight plus three quarters of a complete turn. This yields a very high wire tension on the coil feed wire. The results are a uniform wind and no shift of wire on the form.

It doesn't get better than this. The whole 10 foot tube shows this consistency !
Here is another lathe shot:

This is a picture of the wire spool stand and the tube, at the half way point in construction.

And here is the finished antenna;

I fired this coil up on the low end of forty meters and was pleasantly surprised. I found three resonance points on the tuning capacitor on my MFJ antenna turner, and each time I changed frequency slightly on my transceiver, I had to reset the MFJ unit.
The next step will be a twenty footer !!! Must wait for the return of warmer weather.
A quick note to the coil builder. Stay with the Cantex conduit. I had occasion to try to use brand x PVC electrical conduit for a test trial and ran into serious problems;
1. Check for rigidity. The "x" 10 foot section took a bend on the way home in the back of my car. Not good.
2. Try drilling holes for tap positions. I drilled six holes; two were difficult and four went through the material like butter. Not good.
3. Here's the show stopper. The bell end was not sized correctly. It seized on my sheave mandrel and was an absolute nightmare to remove. Really not good.
In fairness to the conduit industry, I must point out that their product(s) are not designed for my applications.

A new vertical antenna.

2015-10-26T15:37:00.002-07:00

Today a new 10 footer went up, wound with 1/16 inch aluminum wire. The 5356 alloy winds consistently, as shown below. Winding time was approximately 4 hours. If you try this assembly technique, please remember to use loose-fitting gloves and safety glasses !

The finished vertical antenna has continuous coil of 1025 feet of wire !

A New Approach to Winding Aluminum Wire October 8th, 2015, rejected October 11, 2015

2015-10-08T17:54:00.000-07:00

The tried-and-tested techniques used with stainless steel wire do not work with 5356 aluminum 1/16" wire.

The wire kinks and changes position on the coil form after it exits the guiding tool. Any small amount of slack is immediately translated into random wire movement. Back to the drawing board.

We'll start by eliminating the wire bending tool on the feeder stand. Tension on the wire is set by the spring-loaded brake in the wire spool spindle. So far so good. However, the black ABS glue pads that worked well for stainless steel have no effect on the soft aluminum. Time for a new approach.

Here is a test piece with an end-to-end chalk line. This line is the guide for a new tool, the router.

Before routing, we need a tool guide to keep the router from wandering on the tube. Cantex makes a coupler, p/n 6141632, that's just right for riding the tube surface. Here the coupler is cut in half and the inside stop is ground off. The shell is fastened to the router base plate, and we're ready for action.

The router is set up with a 1/2 inch straight bit, and is set for a 7/64 inch deep cut. The theory is that the hard edges made by the router channel will slightly deform the aluminum and hold the coils in place.


The rice-like crumbs from the process fly everywhere ! Keep that ShopVac handy.

Four cuts are made on the tube, each at 90 degree intervals. Next, we roll !

Sunday, 10/11/15; The tensile strength of the wire is such that the grooves proved worthless.
On to plan C.

2015-09-20T08:22:00.001-07:00

Setting up the new 24 inch sheave...Slower surface travel speed and increased torque will yield high-quality coils with uniform spacing between the turns.

The tried-and-true drive assembly is placed in the worktable base.

The support rack idler wheels are centered over the drive pulley and pulled away from the table edge to accommodate the new sheave and flange unit.

The new head stock resting in place and waiting for a new 72" drive belt. C-clamps, a rubber mallet, and shim stock make the project gel in minutes.

Remember to clean thoroughly the bell end of the new tube section. Dirt and other corruption make the joint between the tube and the flange connector difficult to assemble and take apart. One go-around with a 10' section of tube and you'll realize immediately why 4 inch is as large as it gets for this project.

Weight with hardware is 22.2 lbs., and the new travel speed on the 4" work piece surface is 171 inches per minute.

The new travel speed is ideal for 1/16" 5356 aluminum wire. Removing one of the shims, shown stacked to the right of the pulley, allows the operator to rotate the sheave by hand during set up.

Before winding, we'll put on four adhesive strips. Here is the "before" shot.

And here is the "after" result, with the blue painter's tape removed.

General information, September 2015

2015-08-22T09:00:00.000-07:00

The tube section shown above displays the first of four pinstripes made of black ABS glue, each at a 90 degree interval. The edges of the stripes hold the coil wire even on hot, sunny days. When the pipe is free-standing, it will bend slightly in the wind. The wire will move a finite distance on the coil form! The black adhesive will keep the wire secure.

Be sure to have lots of ventilation if you use this stuff !! Most hardware stores

sell Oatey ABS cement in several flavors. Be sure to get the black version.

The data sheet from Oatey is recommended reading;

http://www.oatey.com/doc/medium-black-abs-cement.pdf

Blue painter's tape defines the black channel. Allow the cement to harden for a day before winding wire on the form.

PVC electrical conduit is inexpensive and available everywhere. It's ideal for Tesla coil projects and RF coil forms.

A 10' piece of Cantex 4 inch schedule 40 electrical conduit, part number A52EA12, ready for coiling, is shown below. A plastic scouring pad and windshield washer fluid are used to clean the section prior to winding.

Electrical conduit is designed for above-ground and below ground service, and is stable over a wide temperature range. The Cantex formulation is consistent from lot to lot. The tube does not exhibit "chalking", or surface weathering.

References;

PVC Pipe Association; http://uni-bell.org/

All kinds of useful data here.

Here are two sites that outline the dielectric properties of different plastics, including PVC.

http://www.pupman.com/listarchives/1998/April/msg00337.html

http://www.professionalplastics.com/professionalplastics/ElectricalPropertiesofPlastics.pdf

Cantex pipe data sources;

http://www.cantexinc.com

A thoroughly developed web site; easy to navigate and packed with information.

A copy of the Cantex catalog; http://www.cantexinc.com/resources/product-catalog

http://www.mars-electric.com

My local source for all things Cantex. The company has several stocking facilities in northeast Ohio. Call 800 288 6277 for more information.

Here is an all-band vertical dipole antenna for my ham station. The stand is a discarded safety sign base, and brings new meaning to the term "portable". The wire is 309 stainless steel, .045" diameter.

Above, a re-wound single wind on the same 4" coil form as was used for the dipole.

The wire spacing is determined by the tool shown below.

Several readers have asked for more specifics on the winding guide. The tool shown above is a 3" piece of 1/4" Teflon(R) PTFE tubing with a 1/16" inside diameter. I buy this from McMaster-Carr in Ohio. The part number is 8547K22. It's sold by the foot and is not very expensive.

Two sets of cuts are made on the tubing with a razor blade. The first set is made for the tubing to conform to the coil form as it rotates under the operator's hand.

I use 2 cuts, each at 30 degrees with respect to the tool end, on opposite sides of the tool. Configured this way, the tool rests on the coil form surface without twisting or turning.

The second set of cuts is made on the right and left sides of the tool. These determine the distance between the wire on the coil form and the wire exiting the tool, in other words, the coil spacing.

As shown above, I'm experimenting with a 1.5 times wire diameter spacing for a trade off between the amount of wire on the form and the capacitance between the turns.

http://www.w8ji.com/loading_inductors.htm presents some interesting data on the subject.

http://www.kennethkuhn.com-students-crystal_radios-designing_inductors.pdf has compiled an insightful primer here.

http://www.g3ynh.info/zdocs/magnetics/appendix/self_res/gallery.html has a fascinating article on coil phenomena.

http://www.crystalradio.net/professorcoyle/professorcoylecyl.shtml has a calculator that every Coil Builder will find useful.

As to the type and size of wire shown on theses pages, the best wire is the wire you can get your hands on at the right price.

Adhesive tape is wound on the Teflon(R) tool as a grip pad for the operator. Five or six layers of tape should be sufficient for the operator to hold the tool between the thumb and index finger of one hand without interfering with the winding process.

The Teflon(R) tool material has a very low wear rate. I've used the one you see on six 10' coils and have yet to see any appreciable wear.

2012-12-16T16:04:00.000-08:00

Let's get into production. Always wear loose-fitting gloves and safety glasses.
The motor start switch is mounted just to the left of the wire spool. As the wire is wound on to the tube, the operator moves the wire transport with his/her feet.

2012-12-11T16:54:00.001-08:00

Here is the prime mover for driving the headstock. The wood pillars are not fixed in position; other pulley combinations can be plugged in to give different shaft speeds. Ideally the surface speed on the 4" shaft will be between 175 and 200 inches per minute.

The two small blocks on the bottom allow space for the operator's fingers. Portability and flexibility are key to the construction process.

The small 1 1/2" pulley is fastened to the major 10" pulley with J-B Weld. Scrapped clothes washers and dryers are good sources for pulleys and drive belts of all sizes. In my experience, Maytag and Westinghouse are the brand names to look for.

The motor is a Westinghouse single phase 115 volt workhorse with a 25' cable for the remote on/off switch.