I used a few 9v batts and PhDown. I didn't tweak the voltage for any specific colors, but just aimed for a protective coating. The results were disappointing an

I used a few 9v batts and PhDown. I didn't tweak the voltage for any specific colors, but just aimed for a protective coating. The results were disappointing and probably produced more value in hydrogen than anodization. I might try again if I ever craft something else of aluminum that requires protection.