Aluminum & Aluminum Alloys Steel & Cast Iron Brasses, Coppers, Bronzes & Monel Martensitic Stainless Type 410 Austenitic Stainless Type 302/304, 303, 305 Zinc & Galvanized Steel 1 2 2 3 3 3 Aluminum & Aluminum Alloys 1 1 2 3 Never Recommended 2 Steel & Cast Iron 1, 4 1 1 3 3 2 Brasses, Coppers, Bronzes & Monel