Wood Hardener for Rotted Wood | R400092 Strengthens an reinforces deteriorated wood Extends the life of rotted wood Interior and exterior use Solvent-based Size: 250ml Rustins Wood Hardener for Rotted Wood - 250ml | R400092 A solvent-based moisture-curing polymer solution designed to penetrate deeply and harden rotten or decayed wood. Once fully dried, it strengthens and reinforces the deteriorated wood to support the use of wood filler and provide a seal against further moisture penetration. Suitable for interior and exterior use. Rustins Wood Hardener extends the life of rotted wood, therefore being a cost effective alternative to wood replacement.