Gary, These were stainless steel wires inside protective polymer sheathing, extra thick multiple coatings.
The wires were mounted on a "fence" and then placed under tension to make their resonance from wind, etc fairly high frequency - like the e string on a bass guitar. Seems the tension put so much internal stress into the wires and encouraged so much corrosion that the wires would only last a year, even 2 miles from an ocean. - Robert - On Fri, 10 Oct 2003 14:56:39 -0700 "GARY MCINTURFF" <mcinturff3...@msn.com> wrote: > Robert, > Thanks for the info. Do you mean stress from normal > nut/bolt torque or from a press-fit application. Here is > another small tidbit you might consider - a trick I got > from an aircraft mechanic. Even if the part is stainless > steel if you are working around it with non-stainless > tools you can compromise the stainless part with the > tool. It is the tool material that could be starting the > corrosion. In the particular instance I was discussing it > was stainless steel panels that were being sheared, and > the shear didn't have stainless "shoes" or whatever the > actually shearing components are. These shoes smeared > onto the stainless parts and viola corrosion. When they > put stainless shoes on the shear the problem disappeared. > This was a Boeing 747 crew chief so he certainly has > the experience to make him believable. Might want to > check your manufacturing plant just for grins. > Gary > ----- Original Message ----- > From: robert Macy > To: GARY MCINTURFF ; emc-p...@ieee.org > Sent: Friday, October 10, 2003 12:01 PM > Subject: Re: Corrosion tests - NEBS or Milspec > acceleration factors? > > > > Gary, > > From experience with security systems only "close" to > the > seashore (approx 2 miles away) it is best to *NEVER* > have > any of the metal parts under stress/tension, else the > corrosion rates are incredibly accelerated. > > The particular stainless steel part had been tested > real > time in worse environments with absolutely no > degradation > detectable. Yet, in the actual application under > mounting > stress the stainless steel part repeatably failed > within 1 > year even that far away from the ocean. > > - Robert - > > Robert A. Macy, PE .. m...@california.com > 408 286 3985 . . . .. . . fx 408 297 9121 > AJM International Electronics Consultants > 101 E San Fernando, Suite 402 > San Jose, CA 95112 > > > > On Fri, 10 Oct 2003 09:47:40 -0700 > "GARY MCINTURFF" <mcinturff3...@msn.com> wrote: > > Ernie, > > I know you received Naftali's email so I will > just > > clarify a little more. We test and pass the GR-487 > > outdoor enclosure requirements for the > telecommunications > > industry but I have a client who is non-telecom. > > Telecommunciations customers seem to accept the test, > > because past experience has shown in meets the > equipment > > and time needs (20 years). Non-Telecommunications > > customers not familiar with the tests kind of expect > some > > sort of acceleration factor for the hours under test > to > > demonstrate how long the equipment will work, rather > than > > a more or less pass fail salt fog test. He wants to > how > > long the equipment can withstand the elements at his > > coastal location. Is there any sort of acceleration > model > > used in the salt fog test, or the mixed gasses and > > hygroscopic tests? He is a little unhappy with my > > current response (understandably) that experience > shows > > the test satisfies the screening requirements or else > > they would have been changed long ago to something > that > > did meet the equipment and time requirements. > > Can you give me a little insight? > > Thanks > > Gary McInturff > 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc