Sounds like the makings of a good idea BUT ...

>  You now have a project enclosure that is temp stable
> and
            anything but
>                                     water proof

This ensures it is not pressure sealed:

> Drill a hole near the end of the pipe nearest the surface for wiring
> and seal with silicone.

Hope that the water table is deep :-).

Silicone Rubber is not water vapor proof and will presumably not hold
a pressure seal either. I have NOT tested its pressure sealing ability
but I am sure that , despite it excellent performance as a sealant,
that it is a poor vapor seal.

If you sealed a tube at the top with a solvent attached cap and added
wire entry near the bottom you have a pressure sealed tube which water
level "cannot" [tm] rise in.

Note that the various food storage boxes with clamp down lids and
rubber edge "seals" may be exceedingly non-waterproof in some cases.
In NZ a locally made brand has most of the market and their seals are
not woth being considered as seals.



 Russell
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