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Issues and Inquiries on Phosphating plus ED electrocoating

RFQ: I am looking for a plating company that can plate to this Ford Spec. Phosphate passivate to WSK-M3P1-C electrocoat to WSK-M2P149-A2 color Black. We are in production with this part and our customer wants us to change to this new spec ASAP.


Dan L [last name deleted for privacy by Editor]
a coil spring company - Lombard, Illinois

Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)

How can ED paint be applied to non-conductive zinc phosphate layer?

Q. Dear Sirs

As I have read in some articles about zinc phosphating of cold rolled steel,the crystalline layer on the steel is a non conductive layer.
Note to this fact, would you please explain that how ED paint adheres to this non conductive layer?

Best Regards,

Shahrokh Yazdani
Automotive Paint Shops Equipment - Tehran, Iran

A. Non conductive is always with reference to a maximum voltage limit. Every material is ultimately made up of electrons. Depending upon the thickness, each material has a breakdown voltage specification. And if the voltage applied is more than that, it most certainly will conduct electricity.

Zinc phosphate in bulk might be nonconducting but a 5 micron coating layer on metal is certainly not insulation. And for that matter even E-coating is insulating and it is this insulating property of E-coating that gives it the magnificent feature on uniformity and throwing power.

Any statement must never be studied in isolation.

Gurvin Singh
Mohali, Punjab, India

Q. What stops current from flowing through pipes in ED / CED / Electrocoating

I want to know what prevents current from passing through pipes and pumps on ED paint facility by dipping method.

Muhamamd Yaseen
- Dewan City, Sujawal. Sindh, Pakistan

A. Hi Muhamamd. Plastic pipe is inherently non-conductive. Where metal pipe is used, dielectric unions (or hose joints) break the current path. Good luck.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
July 2013

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