Originally Posted by
John TenEyck
IMO, a 60 CFM fan is of no value unless the open area of your booth is only the size of a shoe box. Spray booths are designed for something like 100 fpm of velocity over the work to carry away over spray. For a booth with an open area of just 2 ft x 2 ft you need a fan with 400 cfm. The open area on my temporary booth is about 4 x 7', meaning my fan should be at least 2800 cfm. So even though my fan may seem large at 1200 cfm, it's not. I'm not sure I follow what your friends at work said about lowering the temp. in your shop. All I can say is that my 1200 cfm fan has minimal effect on the temp. of my shop even after spraying for an hour. Some of my makeup air comes down the chimney (I always turn off the furnace before spraying.), some comes from upstairs via the basement stairs. I think most comes down the chimney, but whatever might be coming from upstairs is already at 65 - 70 deg. If all of your makeup air were coming directly from outside, you might experience more drop in temp. than I have, but I still doubt it would be a problem unless you want to spray non stop for hours.
John