So I seem to issues with bubbling whenever trying to repair pinholes or small cracks in EPS surfboards. I've heard spackling is used to seal EPS before glassing. Can it be used for repairs also?  Any quick fixes? (Epoxy suncure doesn't seem to work due to the bubbles)

make sure the board is in a cool spot. If you are outside and the board might be in sunlight the foam is expanding and will create gas bubbles which escape out the crack...might want to put a little suncure over the spot first (let it dry) which will seal the hole.

lightly warm in sun then use resin and put somewhere cool and it will draw the resin in? don't over stir resin ' let it sit a min or 2 before useing? little thing's like that!

make sure it's dry!!!!!

EPS sucks water even when you thik it is dry there is still moisture in there. Set The board out side in the sun for a few days to gas off the mosture.  Then do as other have said. 

a pal of mine brought me his delam'd Farwar, I routed out he deck, fitted in 2 pound EPS and started to lam over the area. The cloth above the repair kept lifting up like it was a balloon, I'd squeegee it back down and up it came. The board had a gill from the factory, but obviously they don't work, so I stabbed the board with an ice pick about 6" away from the repair. The cloth fell like a cake that had the oven door slammed. Seal any EPS with a thin coat of epoxy, preferably when the temps are dropping, then try to glass.

You're joking right?