Q&A: Pentacryl and Polyurethane
I have a piece of wood which I turned green, then treated with Pentacryl. I then let it air dry about 4 weeks, and then resanded it, and applied a coat of polyurethane. It has been three days, and the coat of coating is still not dry, even after putting it in a stream of air from a fan for hours on end. I feel reasonably confident that the wood was dry as it was not distorting or cracking any. Should I expect a longer drying time for polyurethane, or could there be another problem?
We’re not sure what type of wood or the wall thickness, but it appears that the wood may not have been completely dry before the polyurethane was applied. There may be still moisture in the wood, and the solvent vapors from the Pentacryl have not completely dried – which is preventing the polyurethane from drying.
We recommend you wipe the wood clean with acetone and depending upon the wall thickness and moisture content, let the wood dry for several more weeks prior to applying another coat of polyurethane. The wood should dry slowly, so no air movement, sunlight or heat source – inside a cardboard box is ideal.