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How to protect an outdoor carbon steel forge from corrosion?

August 12, 2008

Can someone recommend a high temperature coating that will also protect carbon steel against rust? I'm working on a new propane forge, which will of necessity be located outside when it's finished. Most of the forge shell shouldn't get hotter than a couple hundred degrees during operation, but localized temperatures around the burner and exhaust ports may go much higher -- perhaps 1000 degrees F, as a guess.

Is there a reasonably affordable coating that will withstand those sorts of temperatures and still provide good protection against rust? I have not had very good success with high temperature grill paint in the past (I have read on this site that the elements of paint that prevent corrosion tend to burn off at high temperatures), and covering the forge with a waterproof tarp or the like only seems to trap condensation.

The ideal solution would be a SS shell, but that's not in my budget at the moment.

Matt Bower
hobbyist - Woodbridge, VA

You've got an annoying problem, copper plating would probably be a good solution. the copper is going to oxidize, so it would have to be thick. I don't know how the heating and reheating is going to affect the finish.
Powder coating could also be a good option, but as this is a gas forge I don't think that it would be a viable option for the burners.

Marc Banks
Blacksmith - Melbourne, FL
August 14, 2008

September 5, 2008

I finally remembered what's probably going to be the best finish for your forge.

Fireplace cement and silica sand.

It reflects heat well and it's watertight.
You can layer it in thin layers with 1/16" layers of kao-wool for extra strength and thermal efficiency.

Marc Banks
Blacksmith - Melbourne, Florida

There are a few places that sell a high temp stoving enamel that is used on jet engines that would probably work. Grill paint will not stand up to the very high temps.

James Watts
- Navarre, Florida
September 9, 2008

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