Chemical Polishing (Bright Dipping) of Aluminum

A. The typical material of construction for bright dip equipment is 316L stainless steel. Be very careful of the L portion; it stands for extra Low carbon. If you don't use all 316L you will get chromium carbide precipitation in the heat affected areas adjacent to welds, which will corrode quickly.

A. Hi, Nathan.

An additional aspect to consider is the need for a special ventilation system. This solution evolves clouds of mustard color toxic NOx, and lip-style tank exhaust is probably not adequate. The bright dip tank and the first rinse usually need to be installed in a "garage" ventilation system, and may require a two-stage fume scrubber rather than a conventional one.

Regards,

A. If you go the route of electropolish instead of bright dipping (its not so extreme in its temperature requirements if that matters, and because of its use of electrical means its more controllable). The problem with the electropolishing being that the only true tank material they've found to hold the electrolyte and maintain a reasonable lifespan is Kynar(tm). Apparently its life is very good, but a sheet of the stuff will set you back 1200-1500 dollars, so you're looking in the neighborhood of 5K+ to put a decent sized tank together. If they could figure out a way around this, they'd have more acceptance I'm sure, but it's a large hurdle to jump for any shop.