[TheForge] Removing Galvanizing (was: Posthumous Demonstration by Jim Paw-Paw Wilson)

[Bruce Freeman]

Jim Wilson's death is as tragic as anything I've recently heard about.  I'll miss him on this and other forums.

The worst of it is that it was entirely avoidable.  All metalworkers should know that there is a simple, cheap, safe (to the user) way of removing zinc from steel:  Pickle it off with muriatic acid.  

The acid need not be concentrated.  Dilute acid will work as well and will attack the iron more slowly after the zinc is gone.   (Always add acid to water, not water to acid.)   Hydrogen gas WILL be given off, so DO THIS OUTSIDE.  Pull the parts out of the pickling bath when the zinc is gone, and before the iron is much attacked.  This means, don't go away and leave them - watch the process.  

The resulting liquid will be toxic with zinc, so keep it and reuse it for the same purpose, adding small amounts of muriatic acid as needed.  Eventually, the concentration of zinc chloride (sometimes called "killed acid" - but there's confusion in such common names) in the solution will be high enough that the liquid might be useful as a soldering or brazing flux.  Remember, though, that use of zinc chloride as a flux will result in zinc fumes.  So use very good ventillation and don't breathe those fumes.

If you must dispose of this material, DON'T dump it down the drain.  Consult local disposal authorities.  It may be a nuisance, but you don't want you dog to eat it, you don't want it in the water you drink or the fish you pull from a local stream.  Where I live, I have to make an appointment, but it costs me nothing to get rid of such wastes.

Bruce
NJ