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Polishing of welded s/steel to a satin finish

We have had to make a canopy in our sheet shop out of 316 stainless 1.2 gauge. We've tig'd the corners on the condensate tray and ground them flat, and discoloration has been treated. Now I need help, how do I get back to my original satin finish without sending to a specialist polishing shop.

Neil David
- Berkshire, UK
2002

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Probably the best method would be to use a non-woven wheel. Depending on pressure, you should be able to match or blend in texture.

AF Kenton
retired business owner - Hatboro, Pennsylvania
2002

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If your parent metal had a 2B finish, commonly described as satin, you cannot imitate it or even approximate it with any finishing or polishing, either in-house or by sending it out. The problem is that 2B is a mill applied finish with the last pass being a cold roll and the surface has absolutely no directional markings whereas removing any weld bead requires grinding and no matter what grit you use, there are always scratches, and if you go too fine the lustre no longer matches. The nearest result may be to mirror finish the effected zone then acid etch or pickle at least that area, but best, the entire workpiece. There are other industry accepted procedures such as "masked passivation" or "strip grinding (or polishing)" that might be acceptable to your clients.

Mick Elmes
- Howick, Auckland, New Zealand
2002