Coating Plated Zinc Jewelry
What is the best way to apply a clear hard coat for durability on plated pieces of zinc jewelry?
Q. I work for a U.S. jewelry manufacturer, and we are looking to add a liquid paint or electrocoating line to coat plated pieces of zinc. What is the best way to apply a clear hard coat for durability on jewelry?
A. For a clear coat on jewelry, I think electrocoating is a good process. To find suppliers of e-coat paints and equipment, go to PFOnline and click on “Suppliers,” then “Electrocoating” and then “Paint, electrocoating” or “Painting Equipment, electrocoating.”
Q. I was told that, since I am using zinc as my base metal, using electrocoating would not work, as the bake temperature would be too high and cause the air molecules in the pores of the zinc to bubble the paint. I was told I needed to use a spray coating because it has a lower baking temperature. What do you think?
A. Oops! I missed the “zinc.” Whoever told you was probably right. High baking temperatures could cause problems with zinc castings in the jewelry. You can use a spray coating with a low baking temperature instead. On the other hand, there may be durable, clear electrocoat finishes with lower baking temperatures that will not cause problems when curing the coating on the zinc castings. I suggest you ask the electrocoat paint suppliers for their recommendations for a lower-baking-temperature material. If that fails, you can always use a spray coating.
E-coat can produce uniform finishes with excellent coverage and outstanding corrosion resistance.
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Better adhesion, enhanced corrosion and blister resistance, and reduced coating-part interactions make pretreatment a must.