“SLICK” E-Coat Revisited



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In the last Electrocoat Clinic there was a question regarding the availability of an E-coat material with a lower coefficient of friction than standard cathodic epoxy electrocoat materials. The writer was looking at the possibility of changing from a dip-spin liquid paint to E-coat. However, the E-coated parts were causing a problem during assembly. There was a “chatter” caused by a stick/slip characteristic of the standard E-coat film.

I made reference to a recent project that I was familiar with where we located an E-coat material that was referred to as a “slick” E-coat. It passed the tests and did not have the chatter. However, processing required racking of the parts, and the added labor kept the cost from being competitive enough to justify the change.

Since then, we have discovered that this material is being economically applied to fastener-type parts. We are grateful to have the following comments from Brian Lowry of Curtis Metal Finishing Co., who has extensive experience with “slick” E-coat. Here are his comments.

“We are quite familiar with standard cathodic epoxy E-coat and its propensity to cause stick/slip or chatter upon installation, both as a fastener coating as well as a bearing surface. PPG has marketed a friction-modified cathodic epoxy e-coat specifically for fasteners that we have had in production more than four years. This process solves the stick/slip issue. It is applied via bulk barrel processing, and is quite economical compared with rack. It also compares favorably in cost with most current dip/spin coatings. This cathodic system replaces the barrel-processed anodic and oil systems that have been around since the late ’70s.

There are three automotive specifications for the cathodic system, offering two levels of friction modification. General Motors uses GM6047-M Code G (Coefficient of Friction 0.13), Chrysler uses PS7902C (CoF 0.13) and Ford Motor Company uses WSS-M21P41-A2 (CoF 0.11). All three of these are in widespread use.”

Brian, we thank you very much for sharing this information with our readers.