Minwax High-Performance Wood Hardener is a quick drying liquid formulated to strengthen and reinforce decayed or rotting wood. The hardener penetrates deep into the wood and its special resin binds and reinforces the decayed wood fibers. High-Performance Wood Hardener seals from further moisture penetration and hardens to a rock hard solid base for filling. Apply with a disposable bristle brush. Allow to harden for 2-4 hours before filling the void with Minwax High-Performance Wood Filler. Cleanup with acetone. Use on windowsills, doors, woodwork, floors, decks, furniture and woodwork.