Dude, go to swaylocks.com and just read through the millions of ding repair threads and you will learn everything you need to know. If this is a board you care about and want it to come out as good as new I would say get it done by a pro, by the sounds of it you don't have the tools/experience to do it right. Just a suggestion though.
I learned ding repairs on some old beat up yellow boards and they turned out pretty bad at first. After a while you'll get the hang of it and now I feel much more comfortable repairing my nicer boards.
Get a power sander if you don't already have one, it will save you A LOT of time and will do a much better job.
So I just got done putting a second layer of glass/cloth over top. Tommorow I'm gonna hot coat and then call it done. Few more questions tho... Today I noticed that the more hardner you add to the mix the more yellow the resin getts. Won't that look badd?? Am I supposed to add extra hardner to the mix with the hot coat or is that just for poly hot coats??? I'm not loving the way it looks now.. I just used epoxy resin to fill the ding (mistake) instead of Q-cell. So now its water tight but not pretty. Don't get me wrong I don't care if its perfect or even a little ugly but I'm hoping you guys have some tricks to make it look a little better then it does now. I've got a couple ideas. Can I put q-cell overr top then hot coat over top of that?? or maybe theres some kind of white paint I can put on it and then fiberglass over that??? Any tips would be greatly appreciated as always guys. Thanks for all of your help so far.
P.S. West Marine is a great source for supplies. Thanks for the tip :)
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.
this is kind of irrelevant to your question but did you ding the wood?
lol.. no disrespect