Rust‐Oleum Self Etching Primer is designed to prepare bare metal, aluminum and fiberglass surfaces to promote maximum adhesion and smoothness of the topcoat finish. Self Etching Primer is a rust preventive coating that etches and primes in one coat. Self Etching Primer features an advanced spray system that allows you to spray at any angle, even upside down for those hard to reach areas. A comfort spray tip with a wider finger pad reduces fatigue caused by continuous spraying.