RE: Masking - was: chassis bonding - star washers enough?
-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
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 --- 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
Re: Masking - was: chassis bonding - star washers enough?
On Fri, 22 Mar 2002 16:53:27 -0800, Chris Wells cdwe...@stargate.net wrote: Masking As to all those who indicate masking off the metal what about oxidation? I'm concerned about the appearance of masking off the painted areas. To avoid corrosion of the exposed steel surface, plating (Zn, Ni, Cr, etc.) can be used. You can mask off only the areas of metal plates where they will be covered by the other metal plates when the enclosure is assembled (i.e. area where the metal surface will contact with the other metal surface), hence it can be designed so that it will not make the appearance poor. Regards, Tom -- Tomonori Sato vef00...@nifty.ne.jp URL: http://member.nifty.ne.jp/tsato/ xvkbd-2.2 (virtual keyboard for X) available --- 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
