The Voice of the Finishing Industry since 1936

  • PF Youtube
  • PF Facebook
  • PF Twitter
  • PF LinkedIn
1/30/2013 | 1 MINUTE READ

Coating Cast Zinc Jewelry

Facebook Share Icon LinkedIn Share Icon Twitter Share Icon Share by EMail icon Print Icon

I would like to comment on “Coating Plated Zinc Jewelry” in your November column. We have been producing plated zinc die castings for 50 years and have been successfully applying clear e-coat to them for 12 years. We apply copper and nickel, followed by brass, bronze or gold, and then apply a 20-micron-thick clear e-coat and bake at 350°F for 40 min.

Q. I would like to comment on “Coating Plated Zinc Jewelry” in your November column. We have been producing plated zinc die castings for 50 years and have been successfully applying clear e-coat to them for 12 years. We apply copper and nickel, followed by brass, bronze or gold, and then apply a 20-micron-thick clear e-coat and bake at 350°F for 40 min.

The key, of course is a dense, porosity-free casting, which we strive to produce continuously. I would greatly appreciate you forwarding our name to your reader—maybe we can help. L.J.

A. In response to that question about using e-coat on cast zinc jewelry, I agreed that high baking temperatures could cause problems with zinc castings, and suggested the reader find a durable, clear e-coat finish that would cure at lower temperatures or use a spray coating with a low baking temperature instead. I referred him to PFOnline to find e-coat paint and equipment suppliers.

As L.J. points out, the key to his success in baking on a clear e-coat is a dense, porosity-free casting. Coating porous castings using baking paints can be a problem because porous castings of most metals can release trapped gasses during the baking cycle, resulting in blisters in the coating. Two solutions to this problem are degassing the casting before coating and producing denser, porosity-free castings. 

RELATED CONTENT

  • Waterborne painting process is a first at South Carolina BMW plant

    PPG launched the first use of waterborne compact paint technology in a U.S. automotive manufacturing plant at the BMW assembly plant in Spartanburg, S.C. This painting process has turned out to be a 2012 award winner and has opened up a new way for auto manufacturers to go leaner and become more efficient in their operations.

  • What is Electrocoating?

    E-coat can produce uniform finishes with excellent coverage and outstanding corrosion resistance.

  • Conveyors and Paint Systems

    Choosing the right conveyor system, coating technology, and ancillary equipment.


Resources