Originally Posted by crashtech
Please provide links to back up these questionable assertions, because I have never seen any epoxy tech sheet that restricts allowable substrates in such a way. The only restrictions I have seen have to do with TPA (lacquer), type of metal conditioning, and acid-etch primers, and of course the normal requirement for adhesion promoter over certain types of TPO, etc.
All epoxies I have dealt with are IDEAL primers for application over plastic filler.
I've done it both ways and a few I wont mention.If anything ,the bondo will suck up the epoxy and dri FASTER than the rest of the car,so I start off by putting two coats on the body work then do the whole car with two to three coats so really the body work gets 4-5 coats but then again I'll sand and block my body work all the way to 320 therefore eliminating the need for any 2k spray on bondo,preperation is everything