Popular Woodworking 2001-12 № 125, страница 19

Exhaust fan

Commercial spray booth

Flexner on Finishing

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a spray booth, could affect your homeowner's insurance, here's how to build a safe, inexpensive spray booth that will be adequate in the volume of air and over-spray exhausted and take up very little space.

The spray booth consists of a fan with a separate motor connected by a fan belt, one or more furnace filters and plastic curtains.

Your choice of fan is determined by the amount of air, measured in cubic feet per minute (cfm), you want to move and is a trade off between better exhaust of over-spray and reducing the need to supply heated make-up air on cold days. In other words, the more air your fan moves, the better the exhaust but the more windows you'll need to open at the opposite end of your shop and the faster the heat in your shop will be lost. Generally, the larger the fan and the more sharply angled its blades the more air it is capable of moving.

To mount the fan, construct a box from plywood or particleboard approximately

one-foot deep with both ends open. The dimensions of the four sides should be adequate to hold the fan at one end and furnace filters, which should be efficient enough to trap all overspray particles before they reach the fan, at the other.

Cut a slot on the top of the box large enough for the fan belt to pass through and mount a motor adequate in horsepower to

drive the fan on the outside of the box. A ^1/4- to ¹/2-horsepower motor (1,725 rpm) would be typical. If you are going to spray solvent-based finishes, an explosion-proof motor is best. A standard TEFC (totally enclosed, fan-cooled) motor will do if you are going to spray only water-base finishes. Either way, the motor needs to be en-continued on page 36

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