Where the
world gathers for metal finishing
Q&As since 1989


-----

Must rust steel. Restoration project at stake!

ooops!really anyone,how do you make new 16 mm rd bar look 200 years old. An entire listed building restoration project is at stake here!

Andrew Stevens
engineering contractor - Wrexham N.Wales, United Kingdom
December 2, 2010

---

Hi, Andrew.

What does the existing 200 year old steel (come to think of it, it's probably iron rather than steel) rod look like? I would imagine that it is not merely rusted, but is cracked nearly all the way through in some areas, with a thick crust, and thinned down to pencil thickness in some areas?

Do you have photos of what you want it to look like? Spritzing vinegar [in bulk on eBay or Amazon] and peroxide on it will make it rust, but if you actually wanted to get deep cracks, crust, and uneven thickness, it's probably difficult.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 2, 2010

Try 1,5-5 % iron(III) chloride solution; Teds advice is good too, you can treat it with very diluted hydrochloric acid, and then with peroxide(3% is ok), instead of acid you can use kitchen salt solution (or even sea water) too. Your object must be grease free! Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia

Andrew

Ted's method should cause rapid rust on mild steel.
But for a conservation project it would be ideal to surface rust and then stop without needing further protection. I would consider CORTEN steel. Outdoors, Wrexham weather should do the rest! (I believe the Angel of The North is corten).

Geoff Smith
Hampshire, England

Consider powder coating that mirrors natural weathering.

Terry Hickling
Birmingham, United Kingdom