# Coil winder



## doc1955 (Jan 26, 2019)

Well started winding my first coil I wound the primary which went pretty good and started on secondary (12,500 wraps).
I've got a plan for the vacuum  chamber in mind and going to start as soon as I get the first one wound up. The wider that I built is working well.


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## tornitore45 (Jan 27, 2019)

Hats off to anyone tackling a 12,500 turns winding with a hair sized wire.
My experience with HV suggest to use a multi section bobbin to lover the gradient.


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## doc1955 (Jan 31, 2019)

Well did get my first coil done AND IT WORKS.  I now need to incase it I'm planning on a box a smaller version of a model T  coil. Here is a pic I took from the video.


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## Ghosty (Jan 31, 2019)

Doc, it looks good, this is what I use as a vacuum chamber, made from a glass dome from an old outdoor weather proof light fitting. Made the base of some alloy plate, with a rubber seal glued to it.
I have an old Robinair vacuum pump to run it.
Cheers
Andrew


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## doc1955 (Jan 31, 2019)

How do you keep a constant temp? With the process I'm doing I have to hold a temp between 185F to 205F depending on the vacuum pulled.


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## Ghosty (Jan 31, 2019)

I use it to pull the lacquer into the coil and than bake separate. You could set the whole thing in an old oven to keep the temp.


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## doc1955 (Jan 31, 2019)

I don't think the wife would allow that LOL. Plus the temp boils off any moisture the reason for trying to get wax sucked in mainly to keep out moisture.


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## Ghosty (Jan 31, 2019)

Doc, put a glass of cold water under vacuum and see what happens, moisture is not a problem.


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## Ghosty (Jan 31, 2019)

doc1955 said:


> I don't think the wife would allow that LOL. Plus the temp boils off any moisture the reason for trying to get wax sucked in mainly to keep out moisture.


I did say old oven, not the good wifes one


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## doc1955 (Feb 1, 2019)

Yes you did but I would have to use hers and that would go over like a lead balloon LOL 
  The crock pot actually worked great for what I wanted and now that I have that setup thats the route I'm taken the only thing I might change is get a longer hose for the pump. 
   I'm going to wind another coil and shoot for  3 to 4 volt and see if I can get it that low and work ok.


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## WOB (Feb 1, 2019)

You are overthinking the vacuum chamber.  A simple Mason style canning jar with a hose barb in the lid makes a perfectly good one. If you need temp control, simply immerse the jar in a water bath.

WOB


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## doc1955 (Feb 1, 2019)

Yes I do that some times LOL. But I have it all set now. 
   Thing is with a jar I would like to know the vacuum value and to get a gauge on it it would have to be a small gauge or a hose to a gauge.


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## barryc (Feb 1, 2019)

When I used to wind HV coils for vehicle Capacitor Discharge electronic ignitions units back in the 60's, I'd immerse the coils in a jar of lacquer then put it into a depressurisation chamber. (The chambers were used to calibrate altimeters - I was in the RAF at the time - so they were pretty handy!) The reason for employing a vacuum is to remove all the air from between the windings to prevent movement ("singing") of the coils during use. It has nothing whatsoever to do with moisture!


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## doc1955 (Feb 1, 2019)

That might be but I am going by the book Bob Shores and he sounds like he was a much smarter individual  than I when it comes to mags and coils. So that is what I was going by it is a very interesting book that he wrote and I did learn a lot by reading it like figuring out the length of wire needed to obtain the resistance of a primary winding. Before I read the book I had no clue.


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## tornitore45 (Feb 1, 2019)

The vacuum is pulled to remove the air so the varnish can reach every place trapped air would impede the impregnation. At that level of vacuum moisture boils off and leaves with the air.  If any air is left a corona discharge takes effect, not a spark just corona. Corona is ionizing and leads to early failure, then you get a real spark inside.
To test for presence of corona we used to connect the shorted secondary to the HiPot AC 60Hz   and the secondary to the HyPot return by means of a 1kohm resistor. Then we look at the V across the resistor with a scope.  The 60 Hz is hardly visible but the presence of corona is indicated by high frequency burst appearing on the top of the 60Hz crests.  If you see that the coil or transformer is going to fail prematurely in continuous use.  A model engine coil may not fail during the few hour the engine is run if that is how long one runs his engines.


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## dsage (Feb 2, 2019)

Tomitore45 - You wrote:
_To test for presence of corona we used to *connect the shorted secondary to the HiPot AC 60Hz* * and the secondary to the HyPot return by means of a 1kohm resistor*. Then we look at the V across the resistor with a scope. The 60 Hz is hardly visible but the presence of corona is indicated by high frequency burst appearing on the top of the 60Hz crests_.
     Was there a typo in there? I'm not understanding that setup. You said you shorted the secondary and connected it to the Hipot tester than you also connected the secondary to the Hipot tester. I'm confused. I'd like to try this test. Could you elaborate.


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## tornitore45 (Feb 2, 2019)

My bad.   The second word "secondary" should read "Primary".
In other words the HyPot is connected BETWEEN primary and secondary to stress the insulation between them.  With this method there is no stress between layers of the secondary, to do this would require a HF induced voltage.
The idea is that if one does not detect corona in the insulation between primary and secondary there is good hope that the varnish has penetrated the secondary as well.


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## mohavegun (Feb 2, 2019)

Made my vacuum chamber as a "bell Jar" using a sheet of rubber mounted on an aluminum plate.  I bought a large clear glass bowl like one would use in the kitchen.  A hose barb was fitted through the bottom of the aluminum and rubber plate and hooked to my vacuum pump receiver. ( I use a receiver to build a vacuum reserve)  It works very well for degassing investment plaster used for lost wax castings and would be perfect for the coil builder as well.  The spherical shape of the heavy bowl is safe enough to support the vacuum.  Will send some pics later.


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## doc1955 (Feb 14, 2019)

Here are some pics of the finished coil. It puts out a nice spark at 6V. The primary resistance is 3.0 ohm and the secondary is at 5600 ohms. I'm happy with the way it turned out one more thing I can cross off my would like to build if I could.


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## mayhugh1 (Feb 14, 2019)

Your photos didn't show up here, but I found them on the other forum. Interesting project and nice final result. I noticed your comment about wanting to rebuild a Model Z buzz box. While watching some of your videos I bumped into one by a guy who showed how he rebuilds the 100 year old Model T boxes. He claims the most common failure is the internal capacitor, and shows where it's at under the tar and how he digs it out. There is also a glass separator plate that has to come out to accommodate the size of a modern replacement cap. I can't begin to recount the number of  high voltage projects I built around those boxes when I was in junior high school. Even today the smell of ozone brings back fond memories of those days. - Terry


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## doc1955 (Sep 21, 2019)

Ok I've wound a few coils now and it is getting easier and easier as I gain the ability. I have ordered some different gauges of magnet wire just experimenting. The last one I wound will give a decent spark at 4 Volts a weaker spark at 3 volts. Runs my Atkinson engine really good and makes it a good starter just barely   flip it over top dead and shes off and running. The one I just finished is about the size of a c size battery. Was going to use the shell of a c size battery but changed my mind and am going to stay away from a metal casing and using pcv instead.  I'm thinking of using a couple of them on my Mini Hog engine.


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## awake (Sep 22, 2019)

Doc, I am very interested in your coil-making. Do you have any plans or resources that you could point me to to find out more about how to do this?


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## doc1955 (Sep 22, 2019)

It is in  the Bob Shores book   Ignition Coils And Magnetos In Miniature
 It is a very well written and interesting book. I do recommend it to anyone that desires more knowledge on coils and ignition systems.


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## awake (Sep 23, 2019)

Excellent, thanks! I have located a copy and look forward to reading it.


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## doc1955 (Sep 26, 2019)

Ok here is a video of the 3rd coil I did it is about the size of a c size battery.


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## awake (Sep 27, 2019)

Enjoyed the video - great job on the coil! Have you made any videos of the actual making of a coil? I'm about 120 pages into Bob Shore's book, and for the most part it all makes sense ... but it would be great to see how it actually works in practice.

Also, where did you source the magnet wire? And did you cut up a transformer for the core laminations?


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## doc1955 (Sep 27, 2019)

awake said:


> Enjoyed the video - great job on the coil! Have you made any videos of the actual making of a coil? I'm about 120 pages into Bob Shore's book, and for the most part it all makes sense ... but it would be great to see how it actually works in practice.
> 
> Also, where did you source the magnet wire? And did you cut up a transformer for the core laminations?



Check this playlist out  
https://www.youtube.com/playlist?list=PLp95TDxCzDrW89zqIXJfeRY5TK7dGSKD2

The wire I got off Ebay it comes from Tempco.

The lamination's came from an old transformer

After making a couple coils I found that I only need 2 drops of wax on the starting end of the wax paper and to not use to much wax. It has gotten easier to wind with every one that I wind I have 5 wound up now.


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## el gringo (Sep 27, 2019)

doc1955 said:


> It is in  the Bob Shores book   Ignition Coils And Magnetos In Miniature
> It is a very well written and interesting book. I do recommend it to anyone that desires more knowledge on coils and ignition systems.


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## el gringo (Sep 27, 2019)

I have an Autographed  Bob Shores ignition winding book I no longer need if there is any interest.
Ray M


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## bluejets (Sep 28, 2019)

doc1955 said:


> Check this playlist out
> https://www.youtube.com/playlist?list=PLp95TDxCzDrW89zqIXJfeRY5TK7dGSKD2
> 
> The wire I got off Ebay it comes from Tempco.
> ...


 
Hat off to you for taking the time to produce the videos.
Terrific achievement.

Only comment is there are times when you are doing things outside the range of the camera but in most instances the commentary covers what you are up to.
One again, great stuff.


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## awake (Sep 30, 2019)

doc1955 said:


> Check this playlist out
> https://www.youtube.com/playlist?list=PLp95TDxCzDrW89zqIXJfeRY5TK7dGSKD2
> 
> The wire I got off Ebay it comes from Tempco.
> ...



Many thanks!


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## doc1955 (Sep 30, 2019)

I wound 2 coils this morning thats 24,000 wraps of 44 gauge wire. I think that will be it for awhile. I'll finish up these 2 and put the stuff away again. The wax is warming up right now that takes about an hour or so to get to temp. I'm finding it pretty easy now after doing (I think) 9 of them now. Good luck and happy winding lol.


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## myrickman (Sep 30, 2019)

If your pulling vacuum on a glass container, you may want to consider wrapping a grid of electrical tape on it as a precaution against implosion. You can still leave some spots open to see what is going on...only takes a scratch to initiate a failure and ruin your day.


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## doc1955 (Sep 30, 2019)

I'm using a mall slow cooker with a thick plexi glass top that I installed a vacuum gauge and a check valve that I attach a hand vacuum pump to. I let the crock pot get the wax to 86 degrees c and then pull a good vacuum on it. So far it has worked out great. I can see the coils and judge when to release vacuum and then re pull a vacuum again I do that several times to remove the air and moister from the coil.


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## retailer (Oct 1, 2019)

Thanks for the videos - I know it takes time to make them.  I have a home made stepper driven coil/transformer winder after watching your videos I may well have a go at making my own coils.


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## bluejets (Oct 1, 2019)

myrickman said:


> If your pulling vacuum on a glass container, you may want to consider wrapping a grid of electrical tape on it as a precaution against implosion. You can still leave some spots open to see what is going on...only takes a scratch to initiate a failure and ruin your day.



Lid is plexiglass, a form of hard impact perspex, not glass as such.


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## bluejets (Oct 1, 2019)

doc1955 said:


> I wound 2 coils this morning thats 24,000 wraps of 44 gauge wire. I think that will be it for awhile. I'll finish up these 2 and put the stuff away again. The wax is warming up right now that takes about an hour or so to get to temp. I'm finding it pretty easy now after doing (I think) 9 of them now. Good luck and happy winding lol.



When we do casting. it tends to be much the same.


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