Monday, July 7, 2014

How to electropolish aluminum

I show a basic electropolishing technique that requires no special equipment and has proven to work well on aluminum (aluminium).


3 comments:

  1. Great stuff, I will give it a try!

    Have you looked at stainless steel cathodes and whether there's a possibility of generating hexavalent chromium in the process? I've come across a lot of conflicting information on the web about the safety of electrolysis when stainless steel is involved, but have steered clear out of an abundance of caution.

    I came across a recipe for electropolishing in the book "Building Scientific Apparatus" which calls for a copper cathode. It was specifically for polishing stainless, though -- 50 parts citric acid, 15 parts sulfuric acid, 35 parts water (all by volume), at 90 celcius and 100mA/sq cm at around 6-12V.

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  2. Brian, I'm pretty certain that home/hobby electropolishing will not produce any significant amount of chromium. The phosphorous compounds that will be formed by dumping the acid into the drain will probably be a bigger hazard if you plan to dispose of the acid in that way. Many municipalities have a local "household hazardous waste" collection center where they will accept acids and dispose properly.

    Thanks for the recipe!

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