Topic: Zinc Phosphate Stripping

I would like to know more about stripping zinc phosphate coating TT- C 490 type 1 from steel panels, for the purpose of verifying the coating weight on the panels. For the longest time our company sent those panels to labs, but now the customer wants the process to become more frequent and internal. I know that we need to purchase a calibrating digital scale and some chromic acid, but i'm not sure if there is another way for recording the coating weight. Your advice would be greatly appreciated