We have a hybrid powder coating (epoxy-polyester) that we apply to our products over an iron phosphate. How much iron phosphate should we deposit onto the substrate to obtain 1,000 hours of salt spray (per ASTM 1654-92)? R.S.
I got into too much trouble answering this same question before. But if you refer to my December 2002 Powder Coating Clinic column “Minimizing Rust” you will see some guidelines. Remember to substitute the symbol ~ for the symbol > when using the suggested coating weights.