Rust-Oleum Stops Rust Primer Sprays provide a sound base for applying Stops Rust enamels on heavily rusted metal. Primers promote topcoat adhesion, help prevent chipping, cracking, and peeling, and eliminate the need for multiple enamel finish coats. It features a comfort tip with a wider finger pad to reduce fatigue caused by continuous spraying and the any-angle tip, which allows you to spray at any angle. Not for use on galvanized steel. 7769 Rusty Metal Primer is designed for heavily rusted surfaces only. 7780 Clean Metal Primer is designed for lightly rusted, bare metal, or previously painted surfaces.