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Corroding steel as a decorative effect

I am involved in the furniture/home furnishings industry, and would like to obtain, on standard sections of square and round steel rod, the appearance of heavy corrosion, the sort of appearance you might see on an old iron gate, left unpainted for decades. I thought that nitric acid would be strong enough to eat away mild steel, but I am not sure how to get the appearance of haphazard pitting. I would be very grateful for any suggestions.

Adrian Parke
product designer - Woodbridge, Suffolk, UK
2007

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2007

Be very careful with that nitric acid idea, Adrian. If you immerse the steel it will evolve clouds of noxious NOx; and remember that nitric acid will ignite flammable materials you apply it with or clean it up with.

But despite what you see in movies, a drop of acid cannot drill deep holes in metal because the dissolution capacity of a drop is very limited (dissolving the metal rapidly consumes the acidity). So I don't think that's the way to deep pitting. How about grit blasting or water jet cutting to 'inflict the damage', followed by a rusting treatment with bleach ⇦ bleach/sodium hypochlorite in bulk on eBay or Amazon [affil links] or one of the dozens of solutions you will see in a very patient search of this site? Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey