Decided to start a spin-off thread. I have an electrical engineering background, an am not a metallurgist or chemist. I spend a lot of time looking at industrial machinery and their control panels. Often, to get a good protective bond (aka safety earth / safety ground etc.) builders scrape off paint (steel) or anodizing coating (alumin[i]um) on part of the machine or cabinet, before attaching either bonding lugs/staps or another part of the machine. (For example, when attaching a control cabinet to a pedestal and both need to be bonded to each other.) This leaves a safety connection with bare steel (or, less common, aluminum). Especially in an industiral environment, the exposed portion will soon oxidize - but what will happen to the conductivity of the connection? If the mechanical connection was made tight soon after the metal was scraped, can I assume that a good electrical connection will exist say 10 years or more from now? If not, what methods should or could be used: - DO NOTHING: scrap to bare metal, connect tightly, no other precautions ? - leave paint in place, instead penetrate paint with star-washer (but I suspect these come loose due to creep) ? - petroleum jelly [e.g. Vaseline brand] ?? - other NON-conductive grease ? - carbon conductive grease ? - copper conductive grease ? - conductive paint ? I'm looking for something that a machine builder can obtain in reasonable quantities at reasonable cost and delivery time. For example - don't like to mention brand names but what about "DeoxIT ® M260Cp Grease (formerly CaiLube), copper particles", www.caig.com <http://www.caig.com/> and distributors. I've never used it. Data sheet looks promising. But is it needed? PS: This started from the earlier thread on Conductive Paint. In searching for "Galvafroid" (zinc rich coating) on the web, I stumbled across "Zinga" anti-corrosion zinc coating system. They say it's not a paint. I couldn't yet figure out if it would be another option.
Regards, Glyn Garside - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
