How does Mastercoat Permanent Rust Sealer work and how long does it last?

Mastercoat Permanent Rust Sealer is a moisture cured urethane. The more moisture in the air, the faster it dries so it’s actually strengthened by moisture. The aluminum powder in the coating cuts off the oxygen so the coating itself is waterproof and air tight. It’ll withstand 8000 hours of salt spray. This product was originally developed in the mid-70’s as a bridge primer. Bridges coated with 2 coats of silver and one coat of color such as our AG111 Ultimate Finish Coating have a documented 20-25 year service life and will take up to 14,000 hours of salt spray.