In particular, note "Nowadays it typically means hot-dip galvanizing"
a chemical process that is used to coat steel
As far as zinc being "poisonous", it might be noted that all of us
using commercially prepared gold alloys inhale a certain amount of
vaporized zinc already. I make my own 14K yellow alloys with 6.6%
zinc. When old golds are repeatedly melted, it is the zinc that
becomes depleted and forces the metal to begin to turn pink. Besides
improving the color, the zinc helps to reduce oxidation of the
copper in these alloys. My concerns are much more centered around
the use of cadmium in solders. Cadmium is a carcenogen.
Zinc is an essential element in human beings, necessary for
sustaining life. Deficiencies of zinc have marked effects on weight
gain in animals. Zinc is found in insulin
, zinc finger
such enzymes as superoxide dismutase
An over supply of zinc has been noted to result in "zinc shakes",
but removal of the subject from the source will result in recovery.
Hard soldering or welding of galvanized iron will result in the
vaporization of the zinc. This means that the zinc plating can no
longer do the job of protecting the iron.
Bruce D. Holmgrain
JA Certified Master Benchjeweler, CAD/CAM Services