Here are some shots of my spraybooth. I made two wooden frames to hold the furnace filters. Vinyl siding "J" channels where attached to the frames so I could slide replacement filters in as they got loaded with paint. One frame was attached to the box fan and the "J" channels sandwiched the plastic sheeting to seal the whole frame, filter and fan assembly. The other frame was attached to the plastic with "J" channels to mount the exhaust filter.
I blew filtered air into the booth to provide positive pressure to keep dirt from getting sucked in. This also kept fumes from going through the fan motor, lessening the chance for a fire or explosion.
Flood lights attached to firring strips provided light on the sides and I hung several flourescent shop lights from the ceiling.
I used 4 mil plastic for the walls and attached it to the framework made from 2" PVC. I used tape, tiewraps and clips to hole the plastic in place and used a large zipper from Home Depot for the door closure.
This booth was built in our hangar, which is attached to our home. During painting, the hangar door was cracked to allow the fumes to exhaust out the hangar door. We move our cars out to keep any overspray that might escape off of them. Paint fumes did not linger and did not intrude into the house. After painting, were were able to safely close the hangar door to maintain heat during winter painting sessions (we live in Wisconsin). We had no problems with fumes or paint getting on anything in the garage/hangar. The booth kept the paint contained and the plane parts clean during painting.
I successfully painted two airplanes this way. My SeaRey was awarded "Outstanding Homebuilt Seaplane" at EAA '02.
I used a Citation HVLP unit with fresh air supply. I liked using the half mask under a hood. The positive pressure under the hood kept all paint and fumes out and I never smelled any paint while in the booth using this setup.
The whole thing cost less that 300 bucks, including wiring and lighting.
Hope this helps and good luck with your paint project.
This is an overview of the booth in our hangar.
This is looking into the booth. The fan and filter are just fastened to the plastic with the "J" channels and the fan sets on some blocks. Keep it simple and cheap.
This is looking out the booth. You can see the exhaust filter and the wood frame that holds it.
Here is a shot of the fuselage being prepped in the booth. You can see the zipper for closing the booth.