Metal finishing Q&As since 1989

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Grainy look under my polished stainless steel

Hello.I have been restoring stainless steel mouldings for my 1965 pontiac. I sanded progressive grits 120, 150, 220,320, 400, 800, 1000, 1500, 25000. Pieces are highly polished with barely a surface scratch visible. It seems though, deep in the part is a grainy look that is not desirable. I wonder what I did ? how can I fix it ?

Boyd Robinson
- Waterford, Michigan
February 3, 2009

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You didn't completely remove some of the coarser scratches. It's difficult to see if you polish following grits in the same direction. If you polish each grit @ 90 degrees to the preceding one, you'll eliminate all the coarse scratches and it will buff out mirror bright.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
February 4, 2009

Thanks for the response.I worked on another piece.Alternating grits and sanding directions.Very confident all sanding scratches were gone.After polishing,a very nice finish appeared.Still leaving a unattractive underlying finish.Is it possible I'm past good metal and into a pitted layer.They do not look appear as pits on top.they look really nice but not like virgin automobile stainless.

Boyd Robinson
- Waterford, Michigan, USA
February 8, 2009

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You haven't mentioned buffing. Are you buffing after the final 2500 grit sanding? You should be using a sewn cotton buff, mounted on a bench grinder, drill press, or even a hand drill, and white stick compound.

No, there is not a surface skin on stainless car trim. It's good quality all the way through.

There is no reason you can't restore them to a near flawless condition as good as new.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
February 9, 2009

Stainless steel is never going to polish up as bright as chrome. Neither will aluminum. Stainless is inherently gray by nature. Are you sure the moldings weren't chromed in the first place, and you just buffed the chrome off? You're probably looking at a nickel underplate...

George Brackett III
- Saco, Maine
February 9, 2009

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Hi Ted, in response to the letter above, one reply was to the effect "stainless will never look as good as chrome". I've seen this comment before, by you, I think. I beg to differ. Here's my 13 year old Caddy.

The bumper is chrome, and the overlay on the lower fender is stainless. I can't tell them apart. Can you? Regards, Jeffrey

Jeffrey Holmes, CEF
Spartanburg, South Carolina
February 13, 2009

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You can polish stainless trim to look almost like chrome. If done properly most people can't tell the difference. However it takes years of experience to learn this art. Trying to tell you how to do it in a few sentences won't work. Learning how to polish requires visual referencing. This skill is usually learned by having an experienced polisher overlooking your work. You have to be shown how it should look after each step, not told.
Take your parts to a good custom plating shop and have them done professionally by an experienced polisher.

Frank DeGuire
- St. Louis, Missouri, USA
February 13, 2009