At 01:43 AM 5/30/2013, Mark Hanchey wrote: >Whenever I see projects for outdoors that need temperature stability=20 >I think one thing, bury it. Buy a short length of 3-4" PVC drain=20 >pipe, 1 end cap, 1 clean out fitting. Place one cap on the pipe=20 >and bury the pipe vertically. Drill a hole near the end of the pipe=20 >nearest the surface for wiring and seal with silicone. Put project=20 >in pipe and screw on clean out. > >You now have a project enclosure that is temp stable and water proof=20 >for outdoors too. There is a site where you can find out what depth=20 >you will need to reach the standard of 50f/10c , most places is about 2 fe= et. >http://www.wcc.nrcs.usda.gov/scan/ I do something very similar for an apparatus that hangs beneath=20 helicopters: its a short chunk of 4" ABS pipe with one end sealed=20 with a glued-in end cap. The other end cap is machined so that it is=20 a sliding fit over the pipe and the pipe has two grooves cut into it=20 for neoprene "O" rings. There is an extra groove machined below the=20 O-ring seal grooves to capture the screws that hold the end-cap on. Everything is lubed with something slippery (DOW Vacuum Grease, I=20 think) and the end cap is just pushed on. Four short screws on the=20 side of the end cap protrude into that extra groove on the pipe and=20 prevent the end-cap for coming off. The center of the removable end-cap has a hole with 10-32 threads=20 that is plugged with a screw and O-ring. When we need to disassemble=20 the unit, we remove the screw and twist in a standard 10-32 barbed=20 air fitting. A quick bast of air pops the end cap off. The field connections are machined right into that removable=20 end-cap. We use hex (1/4") hermaphrodite spacers, 1/2" long, 8-32=20 thread. We use our CNC machine to cut hex-shaped openings in two=20 concentric rings on the flat face of the end-cap, then drill=20 clearance holes for the male part of the spacer. The depth of the=20 hex opening is about half the thickness of the end-cap. It just so happens that the bottom of the hex opening is tapered=20 towards the center hole - not sure why, but its a happy=20 coincidence. We place a small O-ring on the bottom of the hex=20 standoff (the male part), stick that into the hole, then use a=20 ring-tongue terminal on the inside of the end-cap along with=20 lock-washer and nut. That taper at the bottom of the hex opening=20 concentrates the O-ring towards the middle and seals the connection tight. Our initial trials with the enclosure had it sit outside at the=20 bottom of a water-filled 45-gallon barrel (50-gallon barrel for our=20 neighbors in the USA) for a week. Not a trace of moisture inside the=20 enclosure. We've had a few dozen of these in use for many years now. I=20 occasionally get one back for repair and there is not a trace of=20 moisture inside. The exterior usually looks awful but the stuff=20 inside the enclosure is pristine. The customer tells me that they=20 clean everything with a high-pressure wash gun - that includes this enclosu= re. They work very well for something so simple. dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .