I would not bother to seal the hole. I would just stick some masking tape inside trhe pant around the edge. When applying the gelcoat go up to the tape. The hole will be cut out anyway.
Ed, I'm having trouble visualizing what you mean. Do you mean that I should run a strip of tape from the inside, but not completely covering the hole? If so, does that mean when I use the parting board, I'll still have an opening in the pant? So I'll apply the gel coat (or tooling resin I assume) up to and incuding the tape. Then when I apply my glass cloth, it will "bridge" the opening? Sorry for the dumbfounded questions.
Do not take chances with mold release wax. I use only wax that is specifically meant for mold releasing. I will not take a chance with any other product.
Ed,
Do you use PVA too, or just the mold release wax?
Also, I see that West Marine carries Evercoat (Polyester) and Shurhold PVA. Are they OK to use, or should I just go with one from an online source?
Thanks again.
-Jorden