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Rust pitting

Posted: Fri Nov 13, 2009 12:19 am
by Shooting Kiwi
Calling all gunsmiths, engineers and welders...

Do you know of a way of building up very small areas of a steel surface, to build up a rust-pitted surface? I would think TIG welding would be the way to go, but can you run a tiny bead onto a relatively large metal mass, like a pistol frame? And can you do it so that the periphery of the bead is entirely proud of the surface? I've seen scored hydraulic rams built up with electrolytically-deposited chromium, and know about metal-spraying, but are there more delicate, and, preferably, DIY methods?

Posted: Fri Nov 13, 2009 7:46 pm
by JamesH
Need to know the parent metal, what the part is and what its used for, why you want to build it up, how you want to finish it afterwards.

Posted: Fri Nov 13, 2009 9:13 pm
by Shooting Kiwi
Material: steel, alloy unknown.

Parts: slide and frame of pistol.

Reason: cosmetics, but structural integrity must be preserved.

Finish: machine / file / emery paper / re-blue (salt bath).

I accept that this is a fairly pointless endeavor. In this application, it is purely cosmetic. The rust pitting is very local and is probably only a few thou (mil) deep, but it's not possible to take down the surrounding surface until the pitting is removed.

The point that really interests me is whether it is possible to build up a steel surface on a very small scale, say about one mm square, and keep the heating of the component to an absolute minimum. I'm familiar with (some) large-scale surface recovery methods. I was even wondering about local electrolytic deposition, but I suppose it would have to be pure iron, which might not be ideal.