Metal-Prep provides adhesion for POR-15 on any metal surface. Gently etches metal, neutralizes rust and creates an ideal anchor for coatings such as POR-15, while leaving a zinc phosphate finish to ensure chemical bonding of paint and steel. Metal-Prep must be used on galvanized metal, aluminum, stainless steel and smooth, polished or new metal surfaces prior to applying POR-15. Metal-Prep is water-based so it is not caustic, corrosive, toxic or flammable.