Summary for e-coating specification Discussion
e-coating specifications for cold rolled steel in this thread focus on measurable adhesion and corrosion tests rather than a single universal standard. Richard Butler asks how to specify e-coated plates that will later receive polyester powder coating, especially for corrosion resistance and adhesion. Adam Adkisson recommends using a cross-hatch adhesion test, noting the 0-5 scale and saying his shop would reject e-coat below a 4; for corrosion, he points to accelerated corrosion testing such as scribed or unscribed salt spray fog tests and says e-coat with zinc phosphate should be able to pass 1000 hours of scribed salt fog ACT in his experience. In a later question, Roy Booth asks for a military, federal, or commercial specification for e-coating, and a reply identifies A-A-52474 Rev. B, "Electroplating Primer," as a specification to consider.
Q. We plan to source some cold rolled steel plates from China. We want to have them e-coated for corrosion resistance. Once we receive them we will top coat them with a variety of colors of polyester powdercoating. My question is how to specify the properties we want to achieve, especially corrosion resistance and adhesion.
Richard Butler
casual furniture – Granville, New York
2005
A. For adhesion, a cross hatch adhesion specification is the most common method of measurement. The cross hatch adhesion scale is from 0-5, five being the best and 0 being a total failure. You can research CHA testing on the internet.
For corrosion resistance, there are lots of tests that can be done, the most common test that I am aware of is the Accelerated Corrosion Test, that is a salt spray fog test. This test can either be scribed or unscribed, and is rated in hours.
E-coat (w/zinc phosphate) should score at least a 4 on the CHA test, anything lower than that would be grounds for rejection at our shop.
E-coat (w/ zinc phosphate), in our experience, should be able to pass 1000 hours of scribed salt fog ACT tests.
Adam Adkisson
custom coating – Seminole, Oklahoma
2005
Q. I work for a major defense contractor and am interested in specifying an Ecoating process. We usually call out Military, Federal or commercial specification to setup the requirements. I was unable to find a specification for Ecoating. Does anyone have an recommendations?
Roy Booth
– Grand Prairie, Texas, USA
May 23, 2013
A. A-A-52474 Rev. B “Electroplating Primer”
Blake Kneedler
Feather Hollow Eng. – Stockton, California
July 15, 2013