What is used to seal wood that has weep and pitch?

• A. Shellac
• B. Varnish
• C. Polyurethane
• D. Wax

Answer: (A)

Sealing wood that weeps and pitches needs a barrier that blocks resin from migrating into the finish and provides a solid base for the next coats. Shellac does this effectively: it’s a quick-drying sealing layer made from natural resin dissolved in alcohol, which hardens to form a barrier over knots and pitch. Once dry, it accepts topcoats like varnish or paint and helps prevent sap bleed from showing through. Varnish or polyurethane are film finishes that sit on top of the wood and can still be affected by resin bleed, causing issues like staining or poor adhesion. Wax isn’t a reliable sealer for this purpose and can interfere with subsequent coatings. So shellac is the best choice for stopping weep and pitch from affecting the finish.