Brite Dip for Aluminum?

[TomJones]

I have noticed there are a few messages on polishing tread plate and then anodizing it. I use to do a lot of display one of a kind items, including a lot using tread plate. They were never given a polish, weld was left (customer request because I do beautiful welding and then sent out for cleaning, a brite etch and then sealed. When they came back they had a look of being polished. Anyone known how that is done? I did take care in not scratching the metal while fabricating and welding.

[M_D]

It's done with various mixes of acids that are usually heated. Acids have different ways of eating away the metal, a bright dip mix tends the eat the high and thin spots on the surface, thus chemically polishing it.

Most use nitic acid as one main ingredient, which is kind of nasty stuff. I may need to set up a bright dip tank myself, but hate the thought of doing so.