Charles,
     
     Is the PCB totally open to the elements, or is it just that the 
     enclosure it is in isn't totally waterproof?
     
     For the waterproof handheld PCs I design in my present job, it's the 
     enclosure that is totally sealed.
     Most military electronics I worked on in my last job had the fully 
     populated PCBs sealed with a environmental barrier sealant called 
     'humiseal', and the enclosures (which aren't portable) weren't sealed 
     totally along the underside, so that any moisture ingress dripped 
     straight out the bottom.
     
     As for epoxying, it should work so long as the epoxy is UV resistant, 
     and waterproof, and adheres fully to any cables coming through to the 
     outside world. Some potting epoxies give you better heatsinking 
     properties than unpotted boards.
     
     For my home projects, thou, I just stick it in a waterproof box with 
     sealed connectors, or connectors shrouded on the underside if fixed in 
     position. That way I can alter / repair the unit. (without having to 
     dig out the epoxy first!)
     
        Steve Lawther
     
     http://ourworld.compuserve.com/homepages/steve_lawther/ucindex.htm 


______________________________ Reply Separator _________________________________
Subject:      Encasing Pic in Epoxy
Author:  PC:cjoachim@HOTMAIL.COM at INTERNET-HUSKY
Date:    30/01/98 16:42


Hi Guys
     
Just doing a little thinking here and I was wondering what my options 
are to protect circuitry from the elements.  I was thinking of encassing 
the whole controller (PIC, crystal, regulator, adc, etc..) in epoxy to 
protect it from rain, snow, etc...  I'm just curious if this would cause 
the components to overheat and eventually breakdown. Please, if you have 
experience with this sorta thing let me know what you've tried and whats 
been succesfull.
     
Thank you
     
Charles
     
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