MTFCA Forum

I’m almost ready to finish my field coil. Just need to trim the ends, connect and solder, then seal with glyptal. I bought a fairly expensive two-part epoxy for use in electrical applications. I’m wondering if this is necessary to fasten the coils to the insulating paper to the ring. Some coils fit tighter on the poles than others, but after hammering them on with the block of wood, I just don’t see any way of them coming off. I haven’t even gone all the way down yet on them. I don’t really want to remove them just to apply epoxy for fear of damaging the insulating tape in the process, and in the event I have a ground or anything after soldering which would require I remove them, I wouldn’t hold my breath on the tape or insulation staying intact after the epoxy cures.

I’ve never seen any rebuild use adhesive. It looks like the tight fit of the coils on the poles and the glyptal to be enough. However, that assumes that there is sufficient tightness for all coils. I don’t know what “sufficient” would be defined as, but so long as they require a number of hammer ons to lower all the way, I’d think that’s enough.

I’m looking to proceed without epoxying for convenience, cost (if I take the epoxy back), and the ability to undo any mistake down the line before installation in the car. I’m hoping to hear some opinions before I proceed.

2 part might be fine just be sure to read heat and oil exposure warnings or may be overkill. The epoxy should glue the coils to the base. Be sure NOT to coat the areas were it bolts up, contact button and surfaces of the spools. The unit would be fully assembled before coating. If they are really loose, maybe add a paper shim around the inside?

Thanks both.

Steve, I’ve been following your progress on the ring. That rivet that wasn’t counter sunk has made me triple check for my mag post installation. Still not there yet. How high does one need the post and the button?

I took another look at it today. I can remove the coils with my hand quite easily, which is to be expected. A shake of the ring upside down, and the coils don’t even rattle. They stay firm and tight. If that and a few coats of glyptal is enough, I’m happy to proceed with the soldering.

Ryan : Before you put your engine all together , do a test so you know that everything is working properly .
Toon

I’ve decided to do a small test. I’m going to glyptal a small piece of wood wrapped in the tape to a similar surface, and see how well it holds. If it’s alright, I’m going to go ahead without using the epoxy.

Ryan: You do not need epoxy unless the coil is loose on the post. If snug as it should be, liberally/brush coat the back side of the winding and coat the shank of the post w/glyptal and slip the coil on. I made a 'washer' out of 1/8" thick plywood a little larger than the post and laid a block over the washer and used a hand ratchet wood clamp to 'press' the coil on the post. The wood spacer set the coil firmly and squarely on the ring, 1/8' back from the face. I do not think hammering coils in place is ever a good idea. jb