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Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Simulating the crystalline look of hand worn brass
Q. I have seen a crystalline look that brass developed over time from the handling, caused I assume from the oils in human skin. If you polish it, it's gone. Is there a quick process to duplicate this effect?
Mike Dunnhobbyist - Rochester, New York USA
September 14, 2016
A. Whether you can expose the large crystalline structure depends on whether it is there in the first place.
Some brass castings, especially large ones which solidified slowly may have a large structure which you can make visible.
Others may not.
Try cleaning thoroughly with solvents or detergent, then soaking in dilute HCl, say 10%, for an hour or two. You will then likely see the granular structure which may be micro-fine or large.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
September 15, 2016
Yes, I forgot to mention that I think it only occurs in the cast metal, but you knew what I'm talking about. I have some small parts that had a nice granular look that inadvertently polished away. I'll see if I can regain the look. Thanks!
- Rochester, New York USA
September 16, 2016
A. This is from the 1995 Metal Finishing Guidebook and Directory. It's by Nathaniel Hall.
Crystalized Brass or Bronze
copper sulphate
⇦ this on
eBay or
Amazon [affil links] 8 oz
Ammonium Chloride 4 oz
Water 1 gal.
Use either cold or warm. After a crystallized effect has been obtained a dip in a sulfide solution will bring out the crystal effect distinctly.
Dave Wichern
Consultant - The Bronx, New York
September 23, 2016
September 27, 2016
Dave,
Thanks for the reference and recipe. I'll give it a try.
Best,
Mike
- Rochester, New York USA
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