Originally Posted by
LBCrew
First... epoxy has to be mixed by the ratios the manufacturer says... EXACTLY. You can't deviate from the prescribed ratios or bad things WILL happen. Extra catalyst is used in hotcoats for poly only. Epoxy and hardener is not a catalytic reaction. It's an additive reaction... one particle of this matches up with one particle of that. A catalyst only speeds up a reaction that will happen on its own by creating a shortcut. Even hotcoats have limits on how much cat you can add before things get funky... yellow, brittle, hot enough to burn foam and fingers...
Second... there's nothing you can do about it now, except grind it all out and do it over. West Marine epoxy tends to be yellow anyway. Surfboard epoxy should have been the call. White paint won't match... it will be whiter to start and stay whiter as the board yellows. But... do whatever you think looks better at this point. Maybe a dab of white EPOXY pigment in the hotcoat?
Third... you should have just taken it to a ding guy, asked a lot of questions, and let him do the work. Maybe even watched, if he'd let you. You need some foundation of knowledge to start, even just doing dings.