: What? I'm doing it all wrong? Inconceivable!

: Okay, spill it - what type of 'dust blower' are you talking about?

I'm pretty sure he means a dust collection system. Harbor freight has some decent prices on their bottom-of-the line machines. I just got a similar one from Menard's (local hardware chain in the Mid-west) and I'm pretty happy with it.

A shop vac has the motor inside the can. The dirty air in the can is all that cools it. As the can fills the air flow changes and the motor can overheat. They are designed for intermittent use.

With a dust collection system the motor sits outside the stream of dirty air. It is designed for continuous use, much like the fan in you home furnace. It spins a blade, rotor or impeller which sucks in air and sawdust at one end, and blows it into a cloth bag at the other end. On less-expensive units the bag collects the dust. On more expensive units the cloth bag is set up over a plastic bag, or a garbage can. The motor can move a large volume of air, so it picks up a lot of dirt. The dirt can't pass through the weave of the cloth bag, and it is too heavy to stay suspended, so it drops down into the bag or can for easy disposal. Some dirt will stay with the fabric and eventually clog it, so it would be a replaceable item-- but that can take years. More efficient, and more expensive systems use a conical collection area to create a vortex (tornado-like) which gets more of the dirt into the can. The cloth bag lasts longer. More powerful motors, or quieter ones increase the price.

Picture below is from Harbor Freight. The actual motor is not clearly visible. For more details on this, check their website: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97869

: And a few details on the big box filters/ plans would be
: invaluable. I have time now - not much epoxy work at 12 degrees
: fahrenheit. Thanks.

Consider buying someone's old furnace, and throw away the burner and AC part. Just keep the blower and the sheetmetal that it sits in. Or, go to a repair parts shop that sells parts for home heating systems and get a furnace motor and fan. Then make a plywood box for it to sit in. Buy the best (or the cheapest :) ) furnace filters you can get, and make a frame to hold them in front of this. When you turn the fan on it will suck air thru the filter, trapping airborne dust, and blow air out, back into the room. You can filter this output air, too, to get a greater reduction in airborne dust. Replace the cheap filters with electrostatic filters and you'll send more money and remove more dust.

For a quick way to get into this, get a 20" box fan from the local department store. Get a 20 inch square filter and attach it to the intake side of the fan, sealing it on well. Duct tape is the material of choice here. Turn on the fan and set it somewhere in the shop. Whatever air it sucks in will have to pass through the filter, and airborne dust will be trapped. Keep this close to where you are sanding and a lot of the fine sawdust will get trapped on the filter. Hang it from the ceiling and it will circulate air in the shop. When the filter is full, rip it off, and tape on a replacement with more duct tape.

Hope this helps.

PGJ