[TowerTalk] Bentonite

[bthorson at 4smps.com]

Somebody mentioned Bentonite as a good filler material to improve 
grounding a few days ago. I asked around about this a bit and one of the 
tidbits that I got was the following:

Commercial Bentonite comes in two general varieties (at least for 
construction purposes), High Solids and Low Solids. The High Solids form 
was reputedly  good for grounding while the Low Solids form was not. The 
story is that the Low Solids form, while absorbing water as any good 
Bentonite should, would still not be very conductive. However, the High 
Solids form was indeed very conductive when water was absorbed.

The other bit was that it is Thixotropic, meaning that even after 
hardening, it will liquify with a good shaking. So it may be a bad 
choice to have around a tower base, especially in an earthquake zone.

If anyone has any more information on this stuff, I'd be interested to 
learn more.

Ben