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On Sun, Jun 03, 2007 at 04:48:12PM +0000, Peter P. wrote:
> Thanks, I know that it crackles, and I assume that because of that something or
> other changes in it so it is less reversible than before (loses capacity when
> cycled like this or something like that). I also found a large desiccant bag
> marked 'activated bentonite' in a packing carton once. I did not know that
> bentonite could be used as a desiccant (only as absorbent). Imho really wet
> bentonite behaves like wet clay ... or mud. In fact it *is* a kind of mud. I am
> not sure what would happen if the Tyvek bag would tear with wet bentonite in it
> next to a piece of equipment that is supposed to be kept dry. At least silica
> gel does not become any less silica gel when wet. It's still a solid.

Read the wikipedia entry on bentonite... It's interesting stuff, lots of
engineering applications for it due to it's properties in slurry form.

The desiccant I got was actually tyvek bags of bentonite. If you (with great 
difficulty) tear them open it's a fine powder that of course turns into a slurry 
when wet. Trying to get the bentonite wet while still in the bag
though... Well I've had one sitting in a bucket of water for three hours
now and it still feels bone dry.

The tyvek bags are rated to cleanroom 100 standards so from the sounds
of it the dust inside just isn't that likely to get out, the pores of
the tyvek are just too small. If you somehow got them soaked, I'd
suspect whatever was packaged with them would be wrecked anyway.

- -- 
http://petertodd.ca
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