Well, I can second that a bit, but its not about alternators. Years ago, my employer tasked me with building and potting some electrode holders for an arc furnace. They used soft 1/2 inch copper tubes in a coil, potted with "Devcon" brand epoxy and a heat-conducting ceramic filler. The Devcon cost about 200 bucks a quart, and the electrode holders sustained thousands of amperes for months. If I was going to build an alt right now, that is the material I would use. It might be easier and cheaper to find West system epoxy and experiment a bit.