[jan-jaap]

If there are voltages in excess of 320V present then the sealant is really the least of my problems ;-)

From the types robespierre mentioned I can get DOWSIL 738 (but not before August) and 3145 (immediately, but it's €90,- for 90ml). MIL-spec always adds at least one '0' to the price...

I get get DOWSIL 732 for an acceptable price which according to the DOW 'Adhesives and sealants selection guide' is (1) general purpose rather than specifically for electronics and (2) faster to cure. The latter doesn't bother me since I wont be assembling parts but rather just putting a blob here and there.

Alternatively I can get Tecbond 7718 hotmelt from work. It's like hotglue but resistant to 135c instead of the 70c for regular hotglue. It hardens beyond rubbery, but not like 2-component glue which basically becomes glass. I've used it in the past to stabilize Dallas RTC hacks: