I am looking to make a small spray booth in my shop. My question is, do I need a special sort of fan “with an enclosed motor” or can I safely use a standard window fan? Also, are the fumes from lacquer and paint heavier or lighter than air: in other words, should I position the vent of my spray booth high or low?
Michael Dresdner: It all depends on what you plan to spray.
If you plan to spray flammable materials, you will need a special booth, fan, lighting, etc. In fact, you should start by visiting with your local fire marshal and your insurance agent to find out what they will require of you. On the other hand, if you are only spraying waterbased materials, a cheap window or box fan is perfectly acceptable, and entirely adequate.
Consider buying a 20″ by 20″ fan, and also pick up a 20″ by 20″ heating system filter to place in front of it. That will prevent overspray from building up on the vanes of the fan, which will eventually cause it to run lopsided, and destroy the bearings.
Virtually all finishing solvents, with the exception of water, are heavier than air, so I’d place the fan low. Incidentally, waterbased coatings also contain other solvents, heavier than air, in addition to water.