Well, I wasn't able to make an idiot proof part:
- I mixed/brushed on epoxy over the foam (maybe 2 coats);
- then sanded it and finished with bondo and spot putty;
- then high fill primer/sand/prime/sand/prime.
It was quite a respectable looking job after priming.
But since then I had bubbles appear in the finish. I hate doing finishing work.
