Rust-Oleum Stops Rust Rusty Metal Primer bonds tightly to rust to form a surface that topcoats can easily adhere to. This formula drives out corrosive air and moisture other primers leave behind.From the ManufacturerRust-Oleum Stops Rust Rusty Metal Primer stops rust and prevents corrosion. Apply to heavily rusted metal (use Rust-Oleum Stops Rust Clean Metal Primer on clean or lightly rusted metal). Bonds tightly to rust to form a surface top coats can adhere to.