Auto spray booths are very expensive to purchase and install. When painting a vehicle, an auto spray booth is the best place to paint to keep contaminants and debris out of the paint. A spray booth is also ventilated to keep the paint fumes from being breathed in by the painter. Since not everyone has access to a spray booth, a garage can be turned into a spray booth with a few items and proper precautions.
Remove everything from the garage, including everything on the floor, walls and on shelves near the ceiling. Sweep the garage with a broom to remove all dirt and dust. If the walls or ceiling are dirty or have cobwebs, sweep them down also.
Rinse the garage floor and walls, if possible, to remove all dust and debris. When paint is being sprayed on a car, loose dirt and dust in the air can land on the car's surface and show up under the dried paint. Use water to wash down the walls and floor to get rid of most of the dirt.
Cover all items that must remain inside the garage with plastic tarps. This protects the items from paint overspray and also keeps dust on the items from getting into the air or on the car's surface during painting. Dust and dirt particles in the air can land on the car's surface and become very noticeable after the paint has dried.
Place box fans in every window and door opening, facing them to flow outside. This pulls the paint fumes, dust and light overspray outside and away from the painter and the car.
Never paint inside a closed garage without proper ventilation.