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Paint booth extractor fan

Simon Hitchen

Simon Hitchen

Well Known Member
Hi Guys,

Does anyone know of a suitable fan to use as a paint booth extractor fan? Im rebuilding my paint shop and need a bigger fan.

Many thanx,

Simon
 
simon,
for a small roll your own room, i used two gable fans and louvers from lowes. they move about 3600 feet of air each. they clear the 13'x20' room quickly. they are easy to mount and come with a temp/humidistat controller that i removed. the louvers however will stick after a while due to the paint being sticky.
 
There always seems to be a lot of discussion over the need to use a purpose built, non-sparking fan. I've painted several cars, constructing my own booth from pvc pipe and plastic. To avoid the expense and availability of a non-sparking fan, and the issue of a posssible explosion, I've always used standard box fans, but installed them to blow into the enclosure instead of out. A simple square slit on three sides of the poly serves as an exit flap and blows open from the air forced into the enclosure from the box fan. Tape an air conditioning filter to the suction side and then tape the discharge of the fan to the enclosure and start painting.
 
I've painted using 2 of the 20" box fans from WalMart. I buy the furnace filters by the carton from Lowes/Home Depot. I set the fans up to blow OUT, and use filters on the opposite ends of the booth for inlet air, and also place filters over the fans. The fans hold the filters just by suction. In a typical paint job I will go through about 30-40 filters. The inlet ones usually don't need replacing, but the ones on the fans get replaced quite frequently. I'm sure it doesn't meet OSHA standards, but it hasn't blown up yet. I use Dupont products (imron and Vari prime).

Vic
 
I've used a Lowes gable fan on the outlet, painting with Poly Fiber products for fabric. Most of those are high VOC (lots of MEK and the like) and I put lots of overspray in the air with an old Binks #7. Obviously no explosion (I'm still here), but heavy overspray will gum the fan and motor bad enough to kill it due to overheat. So, a catch filter before the fan is a good idea.

The new shop got two Dayton explosion proof fans and catch filter boxes as a permanent installation. The boxes are welded from 1/2 steel angle. Each holds (6) 20x25 and (2) 20x20 filters, just the cheap long-strand variety for a home furnace inlet. With that much area you can spray a long time without loss of airflow.
 
Why not an old furnace blower--centrifugal fan with the motor mounted outside the airstream? An HVAC guy told me that they get them quite often when they replace furnaces.
 
Fan

I used a Home Depot 36" round fan for my temp paint booth. I don't think it's explosion proof but I never had any issues with it. Put a filter over it a you're good to go. I could never put it on high because it would suck the plastic right off the walls. I had eight 20"X20" filters on one end and the fan on the other. It worked very well and would clear the booth in a minute.
 
We used a portable car cover from pep boys, with the side curtin, and a {Heat Buster} fan from sam's, total set up was $400..., if we could attache pictures i would show it but . . .
 
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I've never understood the exhaust vs pressurize issue, except that pressurizing might create a stronger stream of air in front of the fan.

If the box is pressurized, a filter can be placed before the fan & trap all the trash being sucked in. If the fan exhausts the air, pressure in the box is lowered so air (& trash) can enter at any air leak in the box, not just through the filter.

What am I missing?

Charlie
 
rv7charlie said:
I've never understood the exhaust vs pressurize issue, except that pressurizing might create a stronger stream of air in front of the fan.

If the box is pressurized, a filter can be placed before the fan & trap all the trash being sucked in. If the fan exhausts the air, pressure in the box is lowered so air (& trash) can enter at any air leak in the box, not just through the filter.

What am I missing?

Charlie
Click to expand...


The primary issue is air velocity inside the booth. A fan blowing in will push high velocity air into the booth, stirring or carrying dust. Fans blowing out give you the same air exchage rate, but without the downside of high velocity air in the booth, assuming you provide a large enough (filtered) air inlet.
 
other alternative

I built a downdraft spray booth using marine bilge blowers to remove air from the booth. The intake air passes through 2 furnace filters mounted at the top of the booth. The outlet is on the other side of the booth near the floor. The exhaust air passes through two furnace filters and two charcoal filters before it gets to the bilge blowers.
 
the goal is to control the mist as well right? i mean I"m making a rattle can spraybooth, and my primary reason for exhaust vs pressurize is that i want all of the mist pulled onto the air filter
 
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