Our Knot Block Wood Primer & Undercoat completely stops wood knots and wood resins showing through your paint. This primer and undercoat also covers bold colours, dark marks and helps your paint to stick! It makes sure you get a flawless finish that won'y yellow, crack or peel. Perfect for knotty wood like pine.|Guaranteed to completely block wood knots|Ready to paint over in 4 hours|Use on bare or previously painted wood