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How to do Stainless Steel No. 4 finish touch-up?

I would like know how to do touch-up on SS No. 4 finish if there is scratches on the surface?
Please advise process or tools to use ?

Josephine Lim
Production - Singapore
October 13, 2009

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First of all, a scratch is a variation of some surface material. That means that that the surface is uneven along a point or points (line). The only way to eliminate that problem is to change th surface. That means that you must either change that surface or blend in the surrounding surface to minimize the appearance of the points. The best way to do that is mechanically through some abrasive process. The fastest way to do that is with a wheel system; however, that may also mean re-doing the entire surface to blend in the entire surface to a new surface pattern/texture.

AF Kenton
retired business owner - Hatboro, Pennsylvania
October 14, 2009

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Well in a way a #4 weight finish is sort of crappy. We see it all the time on stainless firearms and just about every stainless kitchen appliance we use. It is somewhere between 150wt and 320wt depending on whose definition you use. The problem with the finish is that it is fairly easy to scratch or burnish. Light scratches can be removed with red Scotch Brite pads by polishing in the direction of the original finish. Deeper scratches must be polished out with wet and dry paper or cloth with a carrier or lubricant or a mechanical polishing system. Some times just blending is impossible and the whole unit has to be re-polished. Every job is different.

Rod Henrickson
gunsmith - Edmonton, Alberta, Canada
October 15, 2009

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Thank you for your reply.
Is it possible to polish #4 finish manually?
We are able to manually polish Hairline to blend with the existing finish. BUT We just unable to be able to attain the #4 finish, Is there a certain pattern of stroke or cycle to attain the #4 finish? Any good ideas for us to try? Thanks.

Josephine Lim
- Singapore
October 23, 2009

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I'm afraid the answer is no. Your best bet is to stay with Hairline finish at least you can remove light scratches with the appropriate scotchbrite pad and sand it in the direction of the grain.

Michael Liu Taylor
specialty stainless steel distributor - Dallas, Texas
October 28, 2009

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I have a countertop business and from time to time a piece of stainless gets scratched in the field. It is easy to remove the scratch and get the grain back, but the area that has been worked is shinier than the rest of the panel. I have been told that oxalic acid ⇦this on eBay or Amazon [affil links] can oxidize the stainless and help blend the reworked area into the old. Is that correct? What might you suggest for this purpose?

Andrew Zlot
Countertop repair and refinishing business - Delta, BC, Canada
May 10, 2010