Rust on black steel
Rust on black steel
(OP)
C-Floor Systems is a new composite-action structural floor system using cold-formed steel. One particular client wanted "black" steel to be exposed. Now, naturally, the steel is showing signs of rusting. Is there any advice that anyone can recommend for my client to minimize (or even eliminate) the rusting process without having to paint the steel? I mean, is there some kind of 'oil' or resin that protects the exposed steel while maintaining its "cold steel look"?






RE: Rust on black steel
At any rate, the article acknowledges that reinforcing steel is routinely shipped to the jobsite with such lead time that it sits on site for months before being used. Thus mill scale will develop. The article notes when to clean and when to not to worry about it.
Regards,

Qshake
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RE: Rust on black steel
C-Floor Systems is comparable to Canam's Hambro... except, we use purlins instead of OWSJs.
The rust on the purlins should be avoided. I am not looking for the microscopic stress bonding between a rusted rebar and the concrete.
RE: Rust on black steel
You can use a light oil, but eventually that will allow moisture penetration and will attract dust.
RE: Rust on black steel
You can oil it- works in motors and the like. But the thing is, you'd have to keep oiling them, and it would be a mess. You wouldn't just have a "dry" coating.
On the clear coatings- check with a coating manufacturer. Normally, they'd recommend the coatings on a bare steel surface (ie, sandblasted), not a "black" steel surface.
On the comment as to mill scale up above- I think the mill scale is just formed as the product cools. What happens after that is rust, not mill scale.
Steel gun parts are normally "blued". This involves heating them (I forget, maybe 200 degrees F or so- not a metallurgical process) and applying some sort of solution. But even then, the parts must be kept somewhat oiled, and you couldn't very well do this after a beam is attached to concrete.
You might consider just using an epoxy that is more or less the original color.
RE: Rust on black steel
RE: Rust on black steel
I'm not sure how practical it would be, but it should be possible to use a Zinc "sacrificial" electrode and use the steel joist as the other electrode (not sure which one is the anode/cathode).
I believe they use something similar to protect the GoldenGate Bridge.
cfloor: I would like to "see" some information on the joists.
:)
RE: Rust on black steel