I build outside, Southern California, not too many problems (the builder needs more upgrading than the shop.....)

Here's a tip on dust. I used to have a darkroom (ask grandpa if you don't know). In the first darkroom in a photo studio, I would vacuum, and wipe, very clean-- and the dust just never went away. Then I thought about static electricity. I stopped vacuuming, and just wiped everything down with a wet paper towel. The water coming out of the sink fixture is full of extra electrons. End of the problem.

When I moved to California my darkroom was in an small barn. Sometimes mud and dirt would be on the floor. Almost never a problem with dust, if something did find its way to the negative, just blowing some air would dislodge any.
I used a shop vac, but kept the machine outside and attached a second hose to the outflow and ran it around an outside corner. Vacuum cleaners are notorious for grinding up dust into even smaller particles then spewing them out the outflow. Even if the microscopic dust coming out can't be seen, the positive charge seems to spread to dust in the air.
If you're having a dust problem before your epoxy sets up, there are two types of sources. The obvious one, air blowing dust, knocking it off anything hanging above, the less obvious second source is static charged dust desperate to get those missing electrons replaced. In my experience wet epoxy seems to not be as much of a dust magnet as varnish is. Wetting down the floor can help a lot.

My sympathies for the car paint.
Will

: Unless you like bugs, seed pods, dust, leafs and other items that
: muck up a perfect finish, don't build outside. Considering
: painting the bottom of my canoe, because many more bugs than I
: expected now grace the bottom. I guess I should have built some
: kind of shelter for this instead of just a tarp. Also, on the
: night I fiberglassed, it dewed pretty heavily and turned the
: epoxy milky. The sun got it out, but still.

: I sure wish I had my old shop back.