Summary for phosphating plus ed electrocoating Discussion
The phosphating plus ED electrocoating thread starts with Dan L. asking for a plating company that can meet Ford-style requirements: phosphate passivate to WSK-M3P1-C and electrocoat to WSK-M2P149-A2 in black for a production coil spring part. The technical discussion then shifts to how ED paint can adhere to a supposedly non-conductive zinc phosphate layer. Shahrokh Yazdani asks how this works, and Gurvin Singh explains that “non-conductive” is relative to voltage and thickness: a thin phosphate film on metal is not true insulation, and e-coat itself is insulating, which helps produce uniform coverage and throwing power. Later, Muhamamd Yaseen asks what prevents current from flowing through pipes and pumps in a dip ED facility. The reply says plastic pipe is inherently non-conductive, while metal piping can be isolated with dielectric unions or hose joints to break the current path. Overall, the thread clarifies that thin phosphate films do not stop electrodeposition and that equipment isolation is used to control current paths.
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.
Thanks,
Dan L [surname deleted for privacy by Editor]
a coil spring company – Lombard, Illinois
2003
Ed. note: This RFQ is outdated, but technical replies are welcome, and readers are encouraged to post their own RFQs. But 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
2006
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
2006
Q. What stops current from flowing through pipes in CED
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
2007
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.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
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July 2013