Re: gEDA-user: pcb anti-environment coating?

["Bob Paddock" <bob.paddock@xxxxxxxxx>]

   On Wed, Dec 31, 2008 at 12:49 PM, Bill Gatliff
   <[1]bgat@xxxxxxxxxxxxxxx> wrote:

   DJ Delorie wrote:
   > What's a good thing to coat my built boards with, to protect them
   from
   > the environment?  I've got a temperature/humidity sensor outdoors on
   a
   > small pcb, but I just got done cleaning some corrosion off it.
   Epoxy?
   > Spray paint?

     The product term I've heard is called "conformal coating".  Don't
     know
     precisely what the fundamental stuff is, but there are lots of
     different kinds based on what you need protection from.

   A very common misconception is that Conformal Coating is a Hermetic
   Seal.
   It is used a lot in the Coal Mines, and the Electronic Industry in
   general,
   to keep the caustic dust off circuit boards.

   As Conformal Coating is not a hermetic seal, what real happens is the
   impurities in the water are kept away from the circuit, but the water
   itself reaches the traces. Since the water is now fairly devoid of
   contaminates the water acts more like a dielectric insulator. You
   never notice it in a low impedance digital circuit, but unless
   debugging is an obsession don't let it get near a RF tuning circuit or
   a high impedance circuit.
   --
   [2]http://www.wearablesmartsensors.com/
   [3]http://www.softwaresafety.net/
   [4]http://www.designer-iii.com/
   [5]http://www.unusualresearch.com/

References

   1. mailto:bgat@xxxxxxxxxxxxxxx
   2. http://www.wearablesmartsensors.com/
   3. http://www.softwaresafety.net/
   4. http://www.designer-iii.com/
   5. http://www.unusualresearch.com/


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user