[Milsurplus] Plated steel in WW II

[ed sharpe]

Hansen of Varian fame died of  cadmium poising as I remember.. real bad
stuff.. wear gloves!
ed
----- Original Message -----
From: "aGEnuine ham" <gl4d21@juno.com>
To: <jfor@quik.com>
Cc: <milsurplus@mailman.qth.net>
Sent: Thursday, January 24, 2002 7:28 AM
Subject: Re: [Milsurplus] Plated steel in WW II


> John:
>
> There were two processes generally used in that time frame, cadmium
> plating and galvanizing.  Zinc plating was not yet common.  Galvanizing
> (dipping prepared steel in hot molten zinc) was the process of choice for
> steel which was fully exposed; garbage cans, farm windmills and towers
> being my favorite examples of continuous exposure.  Cadmium, now
> classified as a hazardous substance as it falls into the heavy metals
> category, was easier to plate on complicated shapes, and was used for
> indoor stuff and small hardware.  Zinc in galvanizing provides an
> electrochremical resistance to rust, even when scratched or worn away,
> but cadmium must be a solid coating, like paint, to provide protection.
> Visually, it is often possible to identify galvanizing by the visible
> crystalline structure of the zinc, or by the obvious remains of runs
> while the zinc was still molten.  This is usually obscured in old
> surfaces, however.  New galvanizing is shiny, also, and it takes some
> weathering for it to develop the soft gray look.  Compare an old garbage
> can with a new one for the difference in looks.  Cadmium, on the other
> hand, was pretty dull from the get-go, or at least it didn't take long
> for it to become dull.
>
> I don't know if there are any cadmium platers left because of the
> hazardous materials problem.  Galvanizers still exist, but part of the
> preparation process is boiling in strong acid, so be sure the base
> material is up to that.  Zinc plating, a more recent process may be your
> best bet, but you will have to get some of the antique restorers to tell
> you how to turn it dull more rapidly.  Finally, cold galvanizing spray
> comes out pretty dull, and from a distance is difficult to tell from real
> galvanizing, but it has little resistance to mechanical damage, so it
> isn't satisfactory where parts rub together, or are walked on, for
> example.
>
> Zinc and cadmium respond differently to hydrochloric acid (muriatic acid,
> acid core solder, swimming pool cleaner), but I don't remember which
> response is which.   One turns black, while the other foams.
>
> George W5VPQ
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