- Sep 17, 2008
The etching process (phosphoric acid) leaves millions of microscopic pits for the primer to mechanically adhere to. The alodine process converts a very thin layer of the aluminum to an inert material, resistant to corrosion.This is good. But after the metal conditioner treatment (containing phosphoric acid) prime with epoxy (PPG DPLF). This term "Etch" the metal or apply "etching primer" is stupid. You are "Cleaning" the metal. You ALWAYS want clean metal and the metal conditioner will do it and then it's ready for the primer coat.
Paints of any sort don't stick well to aluminum. It has to be clean, for sure, but it also needs a mechanical bond. Those pits do that.