Now you're gonna' think this sounds nutty as Hell, and I've never used West System to try this out, but it worked extremely well with several, clear, epoxy
resins I've used years ago.
In the late 1980s I used to make some really neat tables from slabs of black walnut, most measuring 7 to 8 feet long and 18 to 24 inches wide. The walnut was sanded with 400-grit wet/dry automotive sand paper, vacuumed, then tack-ragged to remove the tiniest particles, which is imperative.
resin was then mixed, poured on the table's surface, and squeegeed to an even consistency on the entire top. Within a few minutes, bubbles began rising to the surface, thousands of them. The next step, which the first time I did this scared the hell out of me, was to fire up a propane torch and play the flame lightly over the surface. Each and every bubble popped, the finish layed down flat, no dimples were created and the surface dried bubble free. The guy that taught me how to do this said what occurs is the bubble quickly expands and pops before the epoxy
is anywhere close to being cured.
I'm not sure if West System is flammable, therefore I would suggest trying this on a small patch of metal or fiberglass somewhere where it's safe to test. If it is, the technique may still work using a heat gun, but I've never tried using one for this purpose.
I don't believe heating the surface prior to applying the paint
will do anything, but it may be worth a try, again on a small test strip of fiberglass or metal.
Hope this helps,