do you guys use a regular box fan for pulling air out of a booth, or is there any worry of igniting fumes? i have my heater set up to pull 100% outside air, filter it and the pressurize my shop, but i thought maybe the box fan would help.

thanks all sb

please be careful, I had a friend that had an explosion. he was lucky he didn't get hurt to bad. he was standing by a door that had visqween on it and apparently got blown out the door. but the shop and customers car burned up. if your going to use a box fan get one that has a sealed spark proof motor and grounded, not your Wall Mart widow fan. I also have a friend that has a pressurized booth it works very well he turns out nice clean paint jobs. if your having trouble with exhausting paint fumes you might think about increasing your pressure area and or your exhaust area this way your not pulling paint fumes through the fan.
Jay D.

Use those fans to push fresh air into the booth NOT to pull flammable fumes out.
My booth is a positive pressure booth, meaning I force fresh air into it that drives the fumes and overspray out.

Imagine how many shops and backyarders had, and still have woodstoves, pilot lights, LP furnaces burning, etc. in their shops without any issues. The concentration of vapors has to be very high to have an explosion. While I am not recommending a dangerous setup; proper flow, exhaust and fresh air intake will ensure you do not have an explosion.

I worked in a shop in the mid 80's that had a double drum woodstove in which we shot Macks and Peterbilts.

I admit to having done the same but always with good air flow.
Spraying a bunch and then turning the fans on or having not enough airflow is when the danger of an explosion comes in.