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How to stop the rusting process on iron WITHOUT altering the look of the rusted surface?

January 12, 2010

Hi all!
First of all, I've read through some of these articles and this site is damn great!

Well, I'm a French artist drawing on rusted metal sheet. I generaly use Hydrochloric acid to rust my sheets on purpose. I let it evolve and get some cool result...(See my site www.olivierdegea.com to check what I'm talking about... and if you like it, share it!)

But my need now is: how can I stop the rusting process without altering the look that I get with my multilayer Hydrochloric acid application? I tried different things but I can't get the result I'm looking for. For example If I use any kind of vernish the rust becomes dark and almost uniform and doesn't look cool anymore!
I red things about the need of low pH for the rusting process to start. can we stop it spraying some high pH solution on the piece of rusted metal?

Thanking you in adavce for your answers...

Keep up the good stuff!

Olivier de Géa
art - France

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First of three simultaneous responses --

Well when I was in Gunsmithing school back when the earth cooled in Colorado one of my instructors dryly remarked that the very finish that we were putting on our work, black oxide and red oxide was the very thing that would keep us from immortalizing ourselves. Even with coatings of oil and wax the steel somehow finds more oxygen and the rusting process continues be it ever so much slower. Blueing or browning actually slowly gets deeper and more durable with every passing year. And every year, be it ever so little the object gets smaller and smaller. I don't know what to tell you here. In my industry anyway we have never found a way to stop the rusting process and still retain the appearance. History shows that firearms began to crop up around 1100 in China and decorated firearms reared their heads around 1400 to 1500 so conservatively speaking we have been messing with rust base finishes for about 510 years. Some of our more learned and backward thinking colleagues who delve into smelly muzzle loading firearms that are traditionally coated with red oxide have taken to substituting the traditional oil and wax with clear isocyanate based two part epoxy paints. I must admit it looks just like the wax of old but they claim it protects the finish much better. These people also believe that smokeless powder is simply a passing fancy, so whatever! There was however an artist from Australia that posted in here about a year or so back with much the same situation and I know a few of us made some comments. I disremember who she was but perhaps Ted or one of the others can recall it and direct you to her posting. Short of that try some clear epoxy paint. Auto body supply shops carry it.

Rod Henrickson
gunsmith - Edmonton, Alberta, Canada
January 13, 2010

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January 14, 2010

Thanks, Rod. Not sure what thread you are referring to. Maybe 52160? Letters 16945, 17478-2 may help as well. As for Olivier's sketch, wow, what a wonderful piece of art!

Regards,

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

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Second of three simultaneous responses -- January 14, 2010

Olivier,

I must admit to not having a huge amount of experience in this field. Trying to keep it simple and safe, I would suggest a solution of about 5% bicarbonate of soda (sodium hydrogen carbonate) that should be available from your local grocery store. Spray a fine mist over the surface and leave a couple of minutes. Follow up by spraying with water to remove the bicarbonate of soda. Dry the surface, may I suggest a hair dryer ⇦ this on eBay or Amazon [affil links] or something similar to ensure you remove all of the water.

You should then be able to clear lacquer the surface without any further degradation.

Now, before going and spraying this on one of your pieces of work, may I suggest that you try a blank piece first. Make up a test panel and have a go and see how it reacts.

Brian Terry
Aerospace - Yeovil, Somerset, UK

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Third of three simultaneous responses -- January 14, 2010

Sir:

Perhaps you could try "CORE-TEN" weathering steel with 0.10% copper in it. In this case the rusting will be limited to a certain point and then virtually stop corroding. At least that is the theory. Also there are some surfactants (wetting agents) that prevent corrosion of steel. Thus treat your steel with HCl to get the desired amount of corrosion and then coat it with one of these surfactants. I am not sure what the "normal" overcoating should be. I like your art.

Regards,

Dr. Thomas H. Cook
Galvanizing Consultant - Hot Springs, South Dakota, USA

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January 15, 2010

Whaooo!
Thanks a lot for these answers. I'm gonna try some of your solutions and let you know as soon as I get some result...

And thanks for your comments on my art :)

Best regards,

Olivier de Géa
- France