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Products used by the pros in the '70s

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#1 brucefl


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Posted 01 March 2012 - 07:53 PM

I old enough to blame my memory so guys if you can help me remember the product names and companies that sell them from the old days or any improved materials for the same use

Items: Dupont single component epoxy for armature rewinding

Jim Greenaway used to use it; it requires heating in oven to cure (I called Dupont last year but since then I lost the info and no one there now remembers). Koford says they have a 800 degree F epoxy; Dupont says that's impossible since epoxy is organic and so far organics can't get to that threshold.

Magnet wire: I've got SML wire which goes up to 240 C but i've heard about Kapton wire going to 275 C. Anybody hear anything about that. Also I've heard about a ceramic-coated magnet wire which goes up to 1200 F, very expensive and possibly too fragile. Any info? guys.

Commutators: for the '70s vintage style arms pro quality and armature blanks (also for Group 7 modern cars comms and blanks).

Thanks, guys, any help is appreciated.
Bruce Schwartz

#2 Old pink can guy

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Posted 01 March 2012 - 08:24 PM

Bruce in the late 60's I think Mura sold shafts, Arm stacks and the rest. Kirck wood com's were the go to. Belden wire. After I wound a few and used Dubro epoxy and cured them in Mom's oven I did not do any more. That Rolling pin up side my head put that process out of the equation. We need Pdl to chime in for you. Ken.
Ken Botts

#3 havlicek


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Posted 01 March 2012 - 08:42 PM

-You can get magnet wire in pretty much any wire size and half size now and 200C temperature rating is good for about any arm, you can 220C rated magnet wire and it will cost some more...up to you.

-There are several types of epoxies (single and two component) that will handle the heat.

-Actual arm components are difficult to buy. The manufacturers I tried (and I think I hit all the bigger ones) just won't sell them. I tried several years ago when I was getting back into winding and only Mura was willing. The Mura coms are great, but they're very wide. The Mura .007" lam arms I bought had just "OK" coating on them and I had several arms that had internal shorts until I took them apart and recoated them. Also, the .007" lams I got from them are not the same as those used earlier...but they did seem to work very well. Mura will not sell you loose lams to press yourself. In short, getting arm components can be very frustrating. Figuring out how to recycle arms can be a solution but that's also a difficult and frustrating thing. Like anything else, you get better at it with time.

-Good to really good to excellent 2mm shafts are all available. I suggest you buy as few as possible from a supplier until you find out how straight, round and hard they actually are. These make a huge difference.

-Old Mabuchi arms seem to work very well for many applications. The steel seems to be a good alloy and the lams seem to be very concentric (easy to balance). Of course, these are uncoated and rely on fiber end insulators, so you have to keep that in mind when winding...although those end insulators can be modified to work much better. You can also figure out a way to do your own insulating coating on there and just toss the insulators, but it's not as easy as you might think to do a fairly thin/even coating that will effectively prevent shorts.

-Unbalanced modern D motor arms work OK. They have a thinner web (more room), but the Mabuchis seem to work at least as well if not better for most things. YMMV


PS...I forgot to add that, if you plan on doing anything "hot" (say anything hotter than a #29), you should find out about welding/brazing the com connections.
John Havlicek

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