Stainless steel oxide film

[EngineerDave]

Can you recommend any good treatment to remove an oxide film formed on stainless steel to restore it to a shiny surface? I have tried some chemical etchants but they dull the surface due to the darkening caused by etching.

Simply polishing the surface is difficult in this situation due to particles that are brazed to it.

 

[stanweld]

You may wish to try a combination of acids as follows:
1. 10-15% sulfuric/2% HF @ 120F - 150F for 30-60 seconds then Water rinse.
2. 10-15% nitric/2% HF @ 120F - 150F for 30-60 sec then water rinse.
3. 10-15% nitric only @ 120F - 150F for 30-60 sec then water rinse.

 

[TEV]

Anything with HF in it is going to give you some etching. If you need a bright, shiny surface, the best way is electropolishing.

I have seen chemical bright dips for stainless, some years ago. I don't know what was in them. Anybody else know?

 

[EngineerDave]

What about a mixture of sulfuric acid? I may try this as there is copper brazed to the surface and I don't want to damage it. I want to remove the scale on stainless, but don't want to damage the copper.

I will try this and report back. (Samples are relatively expendable)

 

[EngineerDave]

It damaged the copper. Then I remembered, sulfuric cleans pennies! DUH!