Spoke with some folks at the surf expo about hot coat problems and they suggested to try .
1) put cheater coat on blank before lam coat and let cure for 2 couple of hours before you start to lam, Even though you are using cores that are not suppose to offgas , they will.
2) mix hardener 70fast/30slow so it will have enough time for bubbles to rise and pop and melt back in.
3) use propane torch to heat hotcoat up when you start seeing bubbles form , keep flame 4 to 6" away from epoxy and make 2 passes across board.
4) use Methyl Alcohol in spray bottle , light mist cross whole board after hot coat has set up for a little while this will suck out air from epoxy.
5) keep epoxy warm when you are working with it and let it heat up in the cup before you apply.