As a solution to working with a wide range of materials including bare steel, aluminium, galvanized and zinc coated steels, fully cured paints, polyester body fillers and GRP, make sure you are using UPol's Acid #8. An acidic grey primer that promotes adhesion to metal surfaces and suitable for the repair of any damaged paintwork from small scratches to re-spraying of whole panels. A quick, clean and efficient solution that is chromate free.