We use the Plastik70 from Kontakt chemie On Tue, May 15, 2012 at 1:23 AM, Michael Blazer <[email protected]> wrote:
> Here's comparison for various type of conformal coating: > http://mgchemicals.com/downloads/appguide/appguide0404.pdf.< > https://assist.daps.dla.mil/quicksearch/> > > I think there is a type that is 'serviceable' and removable with alcohol. > > Mike > > > On 5/14/2012 6:01 PM, [email protected] wrote: > >> The other option of course is to pressurise the box with dry air to ensure >> a positive pressure differential, such that the net flow is always >> outwards >> at all points, but it's probably easier just to provide a drain hole:-) >> >> However, whilst a drain hole will prevent the build up of a lake inside >> the >> enclosure it still doesn't prevent condensation forming on circuit >> boards, >> and powered circuit boards and condensation don't really go well >> together. >> >> As per earlier comments, it's quite difficult to keep any externally >> mounted enclosure totally moisture free, so it's much easier to accept the >> inevitable and allow for it. >> >> In a past life I designed quite a few circuit boards that were required >> to >> be fitted in externally mounted vented enclosures, so not a great deal of >> pressurisation there then:-), and I usually specified that both sides >> should be sprayed with a plastic coating following final test. >> >> I can't remember now exactly what this stuff was called, but it was >> readily available in the UK from both RS and Farnell as an aerosol >> plastic spray >> that provided a good barrier but was a bit more flexible than the usual >> MOD >> spec conformal coatings. >> It melted easily under a soldering iron, albeit with a foul pong:-), so >> reworking was no problem, and resisted moisture remarkably well..... >> >> problem solved:-) >> >> Nigel >> GM8PZR >> >> >> >> >> >> In a message dated 14/05/2012 23:10:30 GMT Daylight Time, >> [email protected] writes: >> >> The only solutions I think: >> Apply air pressure tight boxes having a breathing hole an the bottom, >> mount the >> box that no rain and water can penetrate from the top or sides. If the >> hole is big enough, >> eg. 2mm, no pressure difference is possible and no pumping effect will >> occur. >> (If the hole is too wide, small animals may penetrate). >> Or, >> when using a pressure tight box, it must be stiff and sealed to >> withstand under all >> temperature conditions more then 1 bar/ 100 kPa. Do not forget that all >> feed >> throughs must be of real hermetic type, normal coaxial connectors are >> not tight! >> Don't route cables directly in, because no cable braid or mesh is vapor >> tight. >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
