[lincpimp]

Well the fans are mainly used to evacuate the overspary, which is the main issue with a closed area. The overspray tends to linger in the air and then fall on the paint as it is flashing off, causing a dry look. The homebrew end draft booth is what I described. It pulls fresh air over the vehicle and sucks the overspray out. Only issue is that you have to paint from the filter end first, so that you do not get the overspray drawn over the fresh paint. Not really a big deal, but it is something to remember.

I have a down draft booth, a big fan draws fresh air inthru a pre-filter, and pushes it thru a giant flat filter above the vehicle, while a second fan draws the air and overspary thru the floor grate and out the exhaust stack. It also has a massive natural gas heater, so that I can heat the incomming air in the winter, to 80f, or bake the vehicle at up to 300f. I usually bake at 140f though, and it recycles the heated air in the bake mode, so not to waste gas.