Thank you guys for these precious advices, I will try the cheater coat on the lam.
As for spackle or wood-oil, I do get these little craters either on the wood side or on the plain EPS surface, my wood is paulownia cheat-coated and very dry anyway. I also spackle the EPS side of the board and then I fine sand it (I will also start sealing it with epoxy from next board).
So it all boils down to accidental micro-contaminations I guess, the cheater coat on lamination sounds like it might fix my issue for good.
Also been tempted to try poly gloss for a long time, always been to affraid to, but I will have to do that, polishing epoxy is getting too time consuming and only looks good for sandad finish, semi-glossy finish with epoxy looks kinda plastic.
I use Resin Research for all my boards. There are strict rules to follow to try to get the hotcoats right. I’ve used other epoxies like, Green Room, Entropy, and Raka, that seem to have better hotcoating results, but there is a reason why RR is the industry standard. I’m a huge fan of xylene for prepping the boards between fill/ hotcoats. It seems to work the best for me, I’ve also heard of people using a fan to blow lightly across the surface of the board to avoid pinholes, but I feel you are risking adding more contaminates to the surface by doing this. When brushing the hotcoat, I use a bit more pressure on the brush and almost plow it into the board, I’ve noticed it tends to bond better and not reject the resin in certain areas. Another thing I do, is sand the board with 100 grit and that will expose the fisheyes, then fill those with a drop here and there or squeegee thickened resin into those areas, then finish sanding the board once cured. Either way, You’re not alone. The whole laminate, then hotcoat, and sand theory is a myth, when using epoxy. It’s simply not as production friendly and requires extra steps that you should be charging for.
GregTate your advice was pure gold, lightly sanded the lam with 120 grit and a very soft pad, then squegeed small amount of resin onto the board, no need to wait for it to settle, I just brushed the rest of the batch after that and not a single hole on a whole 8’2’’ longboard.