Letter 30522

Clear coat finish over rusted metal

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I am a PM and have project with a situation and was looking for any information I could find on clear coat. I have a 20ga colded rolled steel that has been cleaned (w/soap & water) and then we applied a solution of water/acid to speed up the rusting process. We then applied a semi-gloss lacquer (3 coats / interior applicatoin) using a "Deft" product. Now that the metal is in place some of the finish is coming off and taking the rust with it (rusted look was the desire) Is there a product that we can put over the lacquer that will stand up to abuse (prefer clear coat) or do we have to take off the lacquer before we can put anything else on it.

Thank you for any assistance you can offer.

Ed Smith
sheet metal subcontractor - Blue Springs, MO, USA

I have the same interest as Ed in clear coating over a rusted surface. In my case it is for steel sculpture, as I do fairly large pieces for indoor and outdoor use. Many times I want to keep the rusty look. Any suggestions?

Thanks,

Ken MacDonald
- N.Kingstown, RI

Like Ken and Ed I am interested in an exterior clear coat that will work on rusted metal. We are expanding our signage to include etched and distressed metals and need a durable clear for exterior use.

Thanks,

Steve Halmhofer, shop manager
- REDDING, CA, USA

I think that you can use proprietary polyurethane paint or spray. Some of them contains rust inhibitors (Krylon spray). Good luck!

Goran Budija
- Zagreb , Croatia

I have been using the same approach to accelerate rust and have been experiencing the rust peal you describe. It is my belief that the acid causes the rust to happen too fast. I suggest you experiment a little with vineger. That seems to work fairly well and quickly. Also be aware that the texture is different than with the acid.

Allan Polinsky
- Lodi, CA, USA

I am interested in the how much vinegar to mix with water to give me a mottled rusted finish on steel and then clear coat.

John K. Martin
- Rockford, IL, USA

Duh, why coat it with anything? If you want a rusty finish, just leave it alone and it will take care of itself.

Bob Weber
- Shawnee, Oklahoma

If any one knows of a clear surface film finish that could be used over rusted metal I'd really like some feed back on this. I know that you could use Linseed Oil [link is to product info at Rockler] and maintain it every year. the project that I'm working on is Rusted Iron Gates and handrails and its all exposed outside to the weather. Thanks,

Jim Popp
custom painting - Post Falls, ID, USA

I am trying to find a way to clear coat artificial patina without creating bubbles in the clear coat. I am guessing that the chemicals are gassing beneath the surface. Is there a way to neutralize the acids and prevent the gassing?

Olivier M. Odom
metal work - Asheville, NC, US

In Response to neutralizing.... baking soda will neutralize acid. Wipe the surface with water/baking soda mix and drying it fully, quickly. it will stop the patina process.

Kristina Kozak
- Brooklyn

I've been through all the threads, and I didn't manage to find any definitive answers on a clearcoat finish on rusted steel.

I have an old steel welding bench from the 60's, it's rusted to a perfectly natural (almost uniform) rust pattern, and I am using it as a counter in my kitchen. I want to protect the rusted finish with a clearcoat that can withstand plates and dishes and such abrasive surfaces & wet/oily substances.

Is there a product out there that I can use to simply seal the surface the way it is now thus clearcoating it?

Thanks for your help, and for all the info in the threads - very useful indeed

Cheers
Rich

Richard Belliveau
- Fernie, BC, Canada

Hi, Richard. I suspect the reason you couldn't find a clear answer is that there isn't one :-(
It's said that a chain is only as strong as its weakest link. Here we have a link of steel (your welding bench); then a link of loose, powdery, non-adherent rust. Then a link of clear coat. And people report that as stress is put on the clear coat, the clear coat pulls off "taking rust with it".

I suspect that if the rust is quite thin, such that the clearcoat can "wet" it all the way through to where the clear coat can actually grab sound steel, you may get marginally acceptable adhesion.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

I have the same problem as the other people. Have a rebar viewing fence with stucco wall at the bottom. It's supposed to be rusty. But the clear coating the fence people used is washing off allowing it to further rust on the stucco, my flagstone patio and the front sidewalk. Need something to seal it with. Hope you can help. Deborah

Deborah Dillon
- Gold Canyon , AZ

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