I have built many boards both sealed and unsealed on the inside. I have never had a problem with the unsealed paddle boards but you have to remember to close the vent. The only benefit to unsealed is weight savings. All customers boards are sealed on the inside as mistakes happen.

Here is the method I use:

1. I attach the unsealed bottom skin to the frame with PL Premium or 3M 5200
2. All the rest of the wood-to-wood joints are then made with Titebond 3
3. I seal the inside as my last step before the top goes on.
4. I seal the top skin with thinned epoxy (denatured alcohol)
5. Attach the top skin with thicken epoxy.

clayton
www.sliverpaddleboards.com