Sand Throughs Soak Water?

I was told as a kid that a sand throughs on a board will soak up water into the foam. Is this true? It was a reputable shaper that told me this so I didn’t dare disagree then, but now that I think about it the cloth should be saturated and hardened, so I wouldn’t think it would happen. Any thoughts?

basically any disruption in the finish that you can feel when you scratch a nail over it will soak up water and should be sealed. a board is not water tight after lamination…that’s what the hotcoat is for…it fills in the weave.

 Howzit joel, exposed fiberglass will wick moisture and wil eventually get to the foam. the fastest fix is to seal with spray acrylic. Aloha,Kokua