Stuart Longland wrote in
:
I can't remember the details, but I
think he found a part-answer in using lots of PFPE grease to exclude
water. The stuff is often used on vehicles because it tends to stay put
and not form a grinding paste with all the grit that lands on it.
Interesting concept, I wonder how that affects conductivity…
Not a lot, I think.

I just did a test, I smeared a bit of Krytox on the
tip of my index finger, trying to get it even and about 0.25mm thick, then
zapped it with a peizo gas ignitor. It took several shots to get a spark to
find a weak spot through it, or any sensation of electric shock, so I'd say
it's pretty good, and likely to protect against ESD too if you fill a Dsub
pin shroud with it.