Within the last few months, there was a discussion on rec.boats.building regarding the use of "CEPS" (? Epoxy Penetrating Sealer). Supposedly this stuff is specifically formulated to penetrate untreated wood extremely well, seal and provide a good substrate for the subsequent coats of epoxy and glass.

On the "down" side, the CEPS is highly toxic and the fumes require use of some heavy duty breathing protection.

You might try to use dejanews to find the discussion thread.