Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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How can I age steel quickly?
Q. Is there a way to give steel an aged "pitted" finish in a matter of a few hours, a few days or even a week or so?
Jeff Legg- Pineville, Missouri, USA
Q. I too am trying to find a way to pit and age steel quickly. Is there some kind of acid that will do the trick in a manner that would resemble 'natural' oxidation and pitting?
Jim Wooten- Medina, Texas USA
A. Daily misting with vinegar ⇦in bulk on eBay or Amazon [affil links] and salt has been recommended by some people, but try it on something unimportant first..
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. We have been trying to obtain the same finish. We have tried muriatic acid, battery acid ⇦ this on eBay or Amazon [affil links] , vinegar and peroxide. On Hot rolled steel which comes with scale, all we get is a de-scaled piece of Hot Rolled Steel. We were thinking of the salt and vinegar, but where do get large amount of that? I have to do this to thousands of sq. ft. of material in the end. Any suggestions?
April Yacksyzn- Las Vegas, Nevada, USA
September 25, 2012
A. Hi April. Although you can buy "vinegar" industrially as acetic acid ⇦ this on eBay or Amazon [affil links] , it won't work much differently than muriatic acid ... it's just not as strong.
Acid dissolves steel, but it dissolves rust even more quickly. That's the point about "daily misting": you can't dip the steel in muriatic acid because it will simply dissolve all of the rust and a tiny portion of the steel, as you have discovered. "Misting" implies that when the mist evaporates, the steel/rust that was dissolved in it cannot stay dissolved since the acid and water is gone, so it deposits as rust.
You can buy rust patinas, but they won't pit the steel. So maybe the best solution is to splash the steel with muriatic acid until there is some pitting, before thinking about the rusting. Alternately, ferric chloride ⇦ this on eBay or Amazon [affil links] may cause faster pitting than acid. Finally, application of electrolytic action may cause pitting better than immersion. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 25, 2012
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