Lautard has a pic of a homemade unit in one of his Bedside Readers.
It was meant to be hooked up to a Shopvac so that the stuff inside
didn't make it outside. Not sure how long a Shopvac would run with
silica dust and other stuff running through the motor, those filters
don't catch it all. You'd probably want to vent the thing to the
outside anyway. In the powdercoating biz, we had a cyclone separator
to catch the fine stuff along with a bag house for final filtration.
You could make a cyclone separator and one of those woodworking
bag-type dust catchers might work for a final filter.

Stan


A centrifugal air cleaner canister like the ones on earth-moving equipment
might help. The bigger stuff swirls out of the air and collects in the
bottom of the canister where it can be drained off.

WJ