"Dan " Dan@ wrote in message ...
Is this the same steel they use to build bridge beams out of? I was
somewhere that had the bridge beams rusted purposely so they don't
have to paint them. It was either Duluth, or San Diego. How's that for
getting old? Can't remember where.

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.

--
Ed Huntress


On Thu, 6 Nov 2008 10:03:38 -0500, "Ed Huntress"
wrote:


"Bruce in Bangkok" wrote in message
. ..
On Thu, 6 Nov 2008 07:57:19 -0600, "RJ" wrote:


"Randy" wrote in message
m...
On Wed, 5 Nov 2008 21:35:46 -0800, "SteveB" toquerville@zionvistas
wrote:

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.

Steve

WATER?
Add salt to that!

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 :-)

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. g

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-)

--
Ed Huntress