Mechanical wet polish with kerosene avoid any H2O. Water will react with the zinc ruining your sample.
Contact Dr. Tom Langill at the American Galvanizing Association
Thomas J. Langill, Ph.D., Technical Director
tlangill@galvanizeit.org
Phone: 720.554.0900 x14
Fax: 720.554.0909
Address:
American Galvanizers Association
6881 South Holly Circle, Suite 108
Centennial, Colorado 80112
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Here are a few etchants that are typically used for Zinc.
(1) 200g CrO3, 15g Na2SO4, 1000 ml H2O
(2) 50g CrO3, 4g Na2SO4, 1000 ml H2O
(3) 200g CrO3, 1000 ml H2O
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I have seen problems with cracks in the root of fillet welds on galvanized steel.
CLEANING PRIOR TO WELDING GALVANIZED STRUCTURAL STEEL
(1) Mechanically clean the surface with a grinder.
(2) With a neutral torch heat the surface to remove any zinc residual. (A small amount of zinc will be smeared on the surface during the grinding operation.)
Vita sine litteris mors est.