Re: epoxy barrier coat sun exposure how long is too long?
I'm pretty sure those are just air bubbles left when the glass mat was laid up against the gelcoat. It is nearly impossible to get all the air out during layup. Note that non-woven glass mat is ussually the first layer against the gel coat so that the woven cloth pattern doesn't print through the gelcoat. When moisture gets into the glass mat it follows the glass fibers and the fiber changes color in a very obvious way.
Gary H. Lucas