TotalBoat Rust Primer converts rust into an inert substance, stopping rust in its tracks and inhibiting new rust spots. Use it on both rusted or new metal. Using it on new metal ensures superior paint adhesion. Our rust remover is a phosphoric acid-based metal treatment ideal for rusted cars, bikes, boat trailers, campers, farm equipment, tractors, machinery, motorcycles tools, steel doors, steel garage doors, outdoor metal railings, pipe, and other metal surfaces made of steel, stainless, or cast iron. Stop rust right away and make sure it never returns without the need for expensive, time consuming, tedious sandblasting, grinding, or scraping. It's incredibly easy to use. First, use a wire brush to remove loose scale, rust flakes, grease, dirt, and paint. Then brush this thin metal treatment / rust inhibitor on and let it dry overnight. The rusty metal turns black to indicate the chemical change has happened. This means rust has been transformed into an inert state. Brush off any white powdery residue the next day. The surface will be ready for primer. Available in both quart and gallon sizes. Compare to Skybrite or Skyco Ospho, Corroseal Rust Converter, Krud Kutter Rustex, Rust-oleum Rust Reformer, VHT Rust Converter, Gempler's RCQ, MROChem Black Star, CRC Rust Converter, Rust Bullet ProPLUS, Naval Jelly, POR-15, Star Brite Rust Eater, Permatex Rust Dissolver, Evapo Rust, Loctite Extend Neutralizer, Eastwood Fast Converter, and Plastikote.