plating, anodizing, & finishing Q&As since 1989
Clearcoat sealing and finishing of steel
I am looking for way to seal steel. I would prefer an organic approach, but any suggestions would be appreciated. The application is an architectural appearance. The intent is to leave the steel exposed and let the natural beauty of the material show through. Some coloration/discoloration may be okay. I would appreciate any help I can get.Dennis Brun
- Portland, Oregon
Hello, I was searching for natural steel sealers myself on the Internet and came across your inquiry. I see that it is old. Did you come up with a solution? If so, I'd appreciate your sharing it with me. I want to place natural steel in a bathroom setting and I have been told that a lacquer/polyurethane coating is sufficient to protect it. Is this what you heard also? Thanks for any help you can provide.Carol Bronder
- St. Paul, Minnesota
September 2, 2009
it is September 2009 and I am looking for the same answer. I has a black steel mantel made for my fireplace and need to seal it. Did you find an answer to your question?Kerry Ringle
- San Diego, California
September 3, 2009
Hi, folks. There are a number of different single-component and two-part clearcoats available. The banner at the upper right corner of this page shows several brands you can apply yourself, or a local auto body shop can clear coat your parts with a two-component system.
But if you look at the best finish available, i.e., the paint on cars, it consists of --
- galvanizing the metal (dipping it into molten zinc to resist rust), then
- phosphatizing it (to neutralize galvanic hot spots, prevent undercutting corrosion, and add tooth), then
- electrocoating it with a primer (to make sure there is proper coverage in every nook and cranny), then
- painting and curing at least one coat under carefully controlled conditions, then
- two-component clear coating it.
The car companies do all of these sequential and very expensive steps because that is what is required to prevent corrosion in difficult environments. So, will a clear coat alone on bare steel survive? If the conditions are benign, yes, for a few years; if environmental conditions are poor, it won't last a month.
So, my opinions? Dennis: not a chance of clear coated steel surviving an exterior architectural application. Carol: bathrooms are wet and I doubt this will last long. Kerry: I think the mantle will be okay for a reasonable period.
Ted Mooney, P.E.
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