Magneto coils rebuilt question of materials

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Model T Ford Forum: Forum 2017: Magneto coils rebuilt question of materials
Top of pagePrevious messageNext messageBottom of page Link to this message  By Vern (Vieux Carre) on Tuesday, August 22, 2017 - 10:34 am:

Sometimes a picture is just the status quo. The Bendix was removed first before the starter to protect the magneto but when I saw this I purchased a replacement magneto. After reading the manual, the electrical system, and three hours of threads here, I decided that no matter what the magneto should be rebuilt. This one has an open circuit which was traced to the taped coil (I wonder why) and both magnetos have shorts to ground. The coils need to be cleaned, insulated, wound, re-wrapped, inner tabs pointing is alternating directions, soldered, placed on insulators over the iron cores, and adhered down below the surface of the core.
crusty magneto
What materials to use?
I was thinking plastic tape as is used in transformer construction or Kapton tape?
The book calls for the coils to be wound 1/8" oversize in the center but that is for the old school cloth tape - what size with plastic?
There is some sort of card stock, one piece, laid
down, all around before the coils are placed?
Glyptal seems to be the preferred covering but what type of resin to use to keep the coils in place on their core?
Thanks guys!
Vern


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dufault on Tuesday, August 22, 2017 - 11:01 am:

Vern,

For starters:

http://www.mtfca.com/discus/messages/599638/685146.html?1476720158


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Tuesday, August 22, 2017 - 11:56 am:

Most plastic tapes are not going to hold up to the hot oil treatment. The cloth used to cover is not cloth tape, it's a strip of fabric that is wrapped around the coil then held in place by the coating. The winding's are not just wound then turned the other direction, half are wound clockwise and half are wound counter clockwise.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A Bartsch on Tuesday, August 22, 2017 - 12:14 pm:

I highly respect Andre's work. I've used McMaster-Carr Fiberglass cloth tape, p/n 7574A11 for both separating layers and overwarp of wound coils. It is 0.007 " thick, same as original paper strip separator, I use 1/2" wide to wrap coil and split it into 1/4" for separating the turns. (From the MM-C catalog: "Withstands temperatures up to 500 F. Commonly used as a protective wrap for wires and cables, this strong fiberglass cloth tape is conformable, flexible, and abrasion resistant.") Others have used other materials successfully. McMaster-Carr sells various thickness 'fishpaper' insulation for the washers separating coil backs from the ring, I used the 0.020" thick, 12" x 12" sheet, part # 8490K13 $8.62/sheet. good luck, jb


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Tuesday, August 22, 2017 - 12:35 pm:

James;
Is this fiberglass tape sticky on one side or just plain?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Cascisa - Poulsbo, Washington on Tuesday, August 22, 2017 - 01:09 pm:

Here are what they looked like originally.

these are New Old Stock coils.

Be_Zero_Be




Top of pagePrevious messageNext messageBottom of page Link to this message  By Vern (Vieux Carre) on Tuesday, August 22, 2017 - 01:48 pm:

Thanks guys,
Ordered red varnish, went with Kapton tape 1/4 and 1/2".

The fishpaper on McMaster-Car says Max. Temperature: 235 F and nothing of oil resistance?
Boat resin? I found some fiberglass resin in home improvement but still unsure of its usefulness.
Vern


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nicholas Lingg - Tarboro, NC on Tuesday, August 22, 2017 - 01:56 pm:

P D George This is the best you can buy!

http://www.elantas.com/pdg.html


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Tuesday, August 22, 2017 - 02:19 pm:

Vern, this doesn't affect how things work; it's just a little nitpicking on terminology. In the parts book Ford calls that thing the magneto coil assembly. It's commonly called the magneto coil ring, or just the coil ring. The term magneto refers to the whole works, which includes the coil ring and the magnets and other magneto parts attached to the flywheel.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Vern (Vieux Carre) on Tuesday, August 22, 2017 - 02:40 pm:

Steve,
Actually thanks...I had been wondering about that, having seen it used in different ways. The magnets have been sorted out, except for charging, which will happen in the near future.

Nicholas,
Elantas products seem elusive or I need to create an account to see any actual product specs.
Vern

(Message edited by Varmint on August 22, 2017)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Tuesday, August 22, 2017 - 03:05 pm:

Vern,

To make the washers I use 0.25mm gasket paper, as insulation tape I use a good quality masking tape, to warp the coils a 3/8 cotton lint, to fix the coils to the core a hot glue pistol and to finish a all two coats of polyester resin.
First one I did was in 2006 and till now there more as ten running with coil rings I have done , double and single rings, without any problems.
Before glueing the coils on the core I set the core for 30 minutes in an old kitchen oven at 270C to get all the grease and dirt out.

Good luck
Andre
Belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By Vern (Vieux Carre) on Tuesday, August 22, 2017 - 03:34 pm:

Andre, hot glue? wow.
I have a package of hot glue sticks in front of me right now. I'm over-thinking this thing or you're using a special glue?
So, the gasket paper is held down by the coil on top of it, the gasket is not wrapped as part of the coil with the cotton lint and there is no adhesive under the gasket paper. (guessing)
Thanks,
Vern


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nicholas Lingg - Tarboro, NC on Tuesday, August 22, 2017 - 03:36 pm:

Go to your local motor re-winder, They will know all about insulating windings.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Shirley on Tuesday, August 22, 2017 - 03:51 pm:

http://www.mtfca.com/discus/messages/179374/254783.html?1324481291 Shows the method I use.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Vern (Vieux Carre) on Tuesday, August 22, 2017 - 04:07 pm:

Thanks Bob,
That looks awesome. So, just pressed fit and shellac.
Vern


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Tuesday, August 22, 2017 - 04:39 pm:

Vern,
For each coil you need three washers. One is going (glued) between the finished coil and the core. The two others are at each side of the coil before the coil is warped with the cotton.

Andre
Belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Shirley on Tuesday, August 22, 2017 - 05:01 pm:

Thanks, looking back, I did not explain how I cleaned the copper. PreSoak the coils in lacquer thinner, then clamp the end and unwind it use thinner and scotchbrite, apply enough pressure to stretch the copper just enough to make it straight. It will take several trips to get it clean. I don't shellac the wire, many do, but that's why tape is used on both sides of the wire. When it's rolled there are two layers of tape between each layer of wire. Bob 903 824 1949


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A Bartsch on Tuesday, August 22, 2017 - 05:40 pm:

Mark: Sticky one side and total thickness 0.007", same as original paper insulation. jb


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nicholas Lingg - Tarboro, NC on Tuesday, August 22, 2017 - 05:47 pm:

"Nomenclature" Magnet wire is not coated with shellac, it is polyester based and if coated properly it does not need anything else. A good motor re-winder will show you how the wire is wound and then coated. The polyester is like epoxy and will hold everything together.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker, Oklahoma City on Tuesday, August 22, 2017 - 10:26 pm:

I'be always wondered about using Kapton tape. It's thin, inexpensive, good for high temperature (500 degrees F or so) and impervious to just about any chemical known to mankind. And very tough!

I was planning on trying it for my magneto when I get around to repairing it and putting it back in. I just haven't gotten to that point, yet.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Vern (Vieux Carre) on Tuesday, August 22, 2017 - 10:47 pm:

One coil is 11' long unwrapped x 16 coils is 176' of insulation and I bought 200 feet of Kapton, then another 100 feet for wrapping thru the hole. Hopefully, 8 oz is enough varnish for the project. Someone painted the metal backing plate black and it's pealing off but i don't see any reason to make it black again after stripping it because I'm thinking that the wet varnish should be enough to adhere coil to the bare metal core.
Vern


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