Metal finishing Q&As since 1989

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Finish on a stainless sculpture

2007

I am completing a large stainless sculpture comprised of 6 interlocking SS convex disks about 7 feet in diameter each. it is constructed of 304 and welded with 308. The final finish is to be "semi reflective and non-directional". At this point I am blending the welds using an angle grinder [on eBay or Amazon] with 60 > 80 > 120 grit and then to a random orbital with 80 grit and then a course(brown) non-woven pad for the finish. This seems to be working ok. The problem is where the welds are blended out or where I spent more time the orbital(to remove scratches it is brighter. It looks like I have penetrated a layer of oxide...is this correct? 

and if so...

Will it all even out over time?

Should I wash it with citric acid before the final finish? or after?

Any suggestions would be great.

Thanks

Tom Stringham
- East Bethany, New York

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Try Stainless Steel Information Center webpage:www.ssina.com
Hope it helps and good luck¨!

Goran Budija
- Zagreb,Croatia
2007

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It's hard to say what the reason is for the effect you're seeing, but as for citric, we deal with many sculptors who citric passivate their stainless pieces. It does need to be done as the very last step, after all your finishing work is done.

Ray Kremer
Stellar Solutions, Inc.

McHenry, Illinois

2007