I use automotive clear and hardener ( diamont dc5100 clear dh55 activator ). 3 coats makes it just about bulletproof. The problem is getting the wood dry enough to work before the bark falls off. My average is 1 good bark box out of three that doesn't check before I can seal the ends and finish it. More error than trial, but it does make a cool look'n box when everything goes right. thanks for the good comments.... Savage