"JB" wrote in message
news
Mineral Oil (available at your local drug store).

Just be prepared for some strange looks when you purchase a gallon of
mineral oil all at once. :-O

Is motor oil a conductor?

Might burn and sludge up your resistor. Lots of additives you just don't
need.

I had a cantenna for 20 years with light mineral oil. there was a little
seepage to the top of the lid through the vent. I actually had
transformer
oil but never used it because of the thought of that stuff seeping. It
really is a lot cleaner. Check feed stores, Vet supply stores, paint
stores, hardware. Check this out:
http://www.pugetsystems.com/submerged.php


When I was in the Navy, we had some gear that used a high power TWT. It was
immersed in a bath of a fluorocarbon called FC-75, trade name Fluorinert.
Good heat conductor, great insulator, totally inert. Supposedly, you could
drink it. It's still around. Google FC-75 and wikipedia will tell you all
about it. $68/ten gallons is a little pricey for my Cantenna but you might
not think so.

Here's a summary of that chemical family's characteristics for the curious:
http://www.acota.co.uk/products/fluo...tronic-liquids