I found a source for new free corrugated 22 ga bare steel panels 3' wide. I'm going to use them for a shade. The guy said they were 602 or something like that, meaning that the coating on them deteriorates quickly and intentionally so that rust can form on the surface giving it the old barn look. Is there any spray I can put on there to hasten the process? I can get all I want and in lengths up to 16', and for a tip, the fork lift operator loads them for me.
Kind of humorous; all the country boys slapping Koolkote on the rusty roof to make it all new and silvery looking while the city boys are spraying salt water on the roof to make it look all old and rusty :-)
Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom)
It sounds he's talking about A-606, which is basically the same thing as Cor-Ten, except that A-606 is the designation for thin sheet.
This is a self-protecting "weathering" steel. If you're lucky, and if there isn't too much pollution in your air, it rusts into a nice, even, rich brown color in a few years, something like a browned rifle barrel. If you're not lucky, it looks like a rust-streaked wreck for around a decade.
The Picasso sculpture in Chicago's Daley Plaza, made of Cor-Ten, looked like holy hell for years and years. Finally, it started to look decent. I think the problem has been attributed to air pollution.
If it were me, I'd check with someone who knows what he's talking about before trying to accelerate the rusting. My guess is that it will fail. They didn't have much luck in the early days trying to accelerate rusting of Cor-Ten, but, as with nearly everything else, I haven't kept up. d8-)
Yeah, that's the kind of application that Cor-Ten was made for. It came out in the late '70s, IIRC, when I was covering materials for _American Machinist_, and it was being promoted for all sorts of structural and decorative uses. Here in NJ they used it for guard rails on the lower end of the Garden State Parkway. Like most applications, it looked like hell for a few years and then it turned a nice, rich brown. It looks pretty good, and it saves a lot of maintenance cost -- which is the whole point of it.
Because the rust has to form a dense and nearly impermeable structure, it matters how the rust is formed, and I think it matters how fast it's formed. That's why I'm skeptical that you can speed up the process. But maybe they've come up with a chemical treatment for it since those days. I haven't followed it.
I'd spray them with soap to remove any oil, rinse and leave them out to rust by themselves. Wet oak leaves discolor steel quickly. Once they have a rust film, spray on some diluted rust inhibitor such as LPS-3 to stop pitting.
A-606 doesn't pit, Jim -- if A-606 is indeed what Steve has. It's a high-strength low-alloy (HSLA) steel that's formulated to produce a protective coating of rust that, after it penetrates to a certain depth, stops rusting. The rust forms a dense, nearly impenetrable layer.
The Cor-Ten tradename covers a number of weathering steels. The first, Cor-Ten A (ASTM A242), dates back to the 50's. By the time I was taking my structural courses in the early 70's Cor-Ten B (ASTM A588) had obsoleted the earlier material. It was pretty common by that time, if you knew what to look for.
There's at least one more specification for sheet -- the stuff above refers to structural shapes.
We used Cor-Ten for the traffic signal mast arm structures in our town's downtown area, but we did not leave them bare. Instead, we had them painted them a color that was near to their final natural hue. The idea was that they would never be painted again, but we would not have to concern ourselves about pitting in any of the inevitable scratches inflicted during installation, and we would not have to wait for them to age to a pleasing patina.
Did a large steel sign last year. A36 with raised laser cut stainless lettering. They wanted a rusty finish. Knocked off the worst of the dirt and gave it three or four "coats" of the following with a cheap spritzer bottle----- a quart of 3% hydrogen peroxide with a quarter cup of hydrochloric pool acid mixed in. Pretty amazing how fast it works.
Yeah, I guess it was around a lot earlier, from what a couple of people have said. I probably was just on the receiving end of a big promotional push. US Steel was pouring on the PR for a few years, and they were sending us everywhere, from the steel mills of northern Indiana to the coal mines of southern Indiana.