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Conductive powder coat prep

2006

I work for a contract mfgr in Silicon VAlley, CA. and am repeatedly asked to provide a conductive ground point somewhere on carbon steel machine frames that are powder coated. The problem is that the customers don't want the bare ground spot to rust afterward and, don't want to pay for zinc plating before powdering. I've heard and read that phosphating is non-conductive and not suitable for ground points. If this is not the case, then my problem is solved. I've used Conductive paints (such as copper, zinc, and carbon filled) on the bare spot but find that two baking cycles are needed due to the differing bake temps. Is there a relatively inexpensive process by which a carbon Steel Frame can be completely cleaned of all oil and contaminants both inside & outside of the tubes, provide fair corrosion resistance, yet not leave behind a non-conductive surface that would need to be mechanically removed (scraped) for good conductivity? Cudos to anyone who can solve this!
Thanks.

Jess Craig

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October 2, 2008

We have used 50-50 lead tin solder paste on ground points like you describe. The powder doesn't stick well to the solder so around the edges we need to sand. The problem we have now is RoHS compliance. In semi-conductor the copper based solder is not acceptable.
We are currently looking for a substitute currently. Any suggestions?

Scott Huffman