Few woodworkers can afford a purpose-built spray booth, especially one that meets health and safety codes for spraying solvent finishes. At the other extreme, waiting for a fine day and spraying outside also is fraught with problems. The wind blows the spray back in your face, and every bug in the neighborhood dive-bombs the wet finish.
The spray booth here should cost less than $200 and will allow you to spray indoors in a controlled environment. The booth is designed just for water-based finishes, however. I advise you not to spray flammable materials indoors unless you have a dedicated room outfitted with an explosion-proof fan and explosion-proof lighting fixtures.
The booth design
When spraying indoors, it's important to evacuate the overspray produced by the gun, not only for health reasons but also to prevent the atomized overspray from settling on your furniture and creating a rough surface. The booth shown below accomplishes that.
A basic booth. Three rigid-foam insulation panels form the sides. A fourth panel makes the top, holding everything stable with furring strips. A furnace filter and box fan provide ventilation.
Cut a hole in the center panel about 30 in. off the floor. Slide a furnace filter in front of the hole, and rest a box fan on sawhorses on the outside. Use a cheap, open-weave filter. The more expensive kinds designed to trap minute particles will get clogged with finish too quickly.
The booth in use. The box fan draws fumes and overspray outside. To do that, there must be a source of fresh air, such as an open door or window behind the operator.
When spraying, you will require bright lighting in the booth to differentiate between wet and dry areas. I like to use halogen work lights on a tripod.
The 4-ft. by 8-ft. foam panels can be cut easily to fit any location. When folded for storage, the booth is less than 2 ft. deep and light enough to be carried by one person.
Photos: Mark Schofield. Drawings. Vince Baback