>-----Original Message----- >From: Doug McKean [mailto:dmck...@corp.auspex.com] >Sent: Monday, March 25, 2002 6:16 AM >To: EMC-PSTC Discussion Group >Subject: Re: Masking - was: chassis bonding - star washers enough? > > > >Very good question. > >In my experience, the corrosion issue with >regard to masked off areas has never been >a factor. Yes, it will corrode, but the teeth >will cut through that. The masking off of >areas has also been internal to the product. >Yes, I've also used the star washers on painted >areas (non-conductive paint at that) without >a problem, but my *preference* is masked >off areas. > >If you're subjecting your product to some >extremes in environment other than normal >office environment, then corrosion will most >definitely be a concern. > >If you're going to use star washers on surfaces >painted with non-conductive paint, then you >may want to consider using a torque wrench >for securing the nuts or bolts during assembly. > >Regards, Doug McKean
The military generally doesn't like toothed lockwashers because: 1. As the teeth cut into the surface, you generate bits of paint and base metal particles. That's not nice, because the particles can cause mechanical and electrical problems. 2. Any fault current is conducted through the relatively small cross-section contact points. This can result in arcing and even vaporization of the conductive path. Look at MIL-B-5087 for typical military bonding and ground stud practices. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
