PB: I assume from your post that you are trying to seal the wood before final finish. Is that correct? Here is a medium that painters have used for years. 1/3 turp, 1/3 blo, 1/3 varnish. Mix all together and give it a few "spit coats" of that. Let it dry for a couple days before finishing. PS... Make sure your varnish is good, that stuff will go funky once in a while. Hope this was your question, if not just take it as the rumblings of an old man.