I would like to build an 8′ x 8′ x 6′ deep spraybooth (for shellac and lacquer), with an 8′ x 6′ filter wall (can’t afford a commercial unit). By my best calculations it needs to move 4800 cfm, and an 18″ 1 1/2 HP fan will do the trick. All I have been able to find is a Grainger tubeaxial fan, #7F954, for $747.00 +SH. Any ideas on a less expensive way?
How deep should the chamber behind the filter wall be leading to the fan opening (my space is very limited)? Should there be baffles in this chamber, or can it be left open?
Thanks for your time, and any ideas you can offer. Rand
Edited 10/15/2005 12:28 pm ET by randhall
Replies
Your 18 inch fan being mounted at the top of the plenum probably decides how deep the chamber (plenum) will be. My guess is 20 inches or so. Put 4 x 4 welded wire mesh up on metal studs 20 inches on center and standard filter media will fit against the mesh which should have 4 wires cut sticking into the spray room to hook the filters on to. Its very easy to make with cheap materials. Turn the fan on, paint laden air gets sucked through the filter media and voila-pretty close to legal. aloha, mike
Mike,
Thank you for your quick and informative reply. I can picture the plenum construction easy enough-great idea with 4x4 mesh. Haven't begun checking local sources for filter material, tho, and am not sure what you are referring to. I was envisioning something like a replaceable heater filter. Your idea sounds more like a full size sheet of something? Source?
Again, thanks for all your help. Rand
Rand, the filter media is standarized for this use and available at automotive paint dealers. I prefer the fiberglass type over the woven paper or styro. They are 20 x 20 inches, hence the recommendation. You just push the filters onto the 4x4 mesh with the occaisional bent forward wire. I like 4 wires sticking out to me per 20x20 for easy placement and removal when they are full. Have fun! aloha, mike
randhall
I am in the process of building a spray booth in the back corner of my shop. The dimensions are 8'x10''x7'. I will have to check the specs on my fan but I am turning the air about five times a minute. The fan cost much less than the model from Grainger. It has the louvers that open when the fan is turned on. I am using fifteen square feet of paint booth filters for the air coming into the booth and I am covering the fan with a furnace filter that is about four square feet.
Below is a website for the company that manufactured the fan I am using.
http://www.trianglefans.com/gpx.html
Good Luck
Grits
Edited 10/16/2005 3:12 am by Grits
Edited 10/16/2005 3:13 am by Grits
Grits, that fan will work but..... if there is a spark or heat build up in the motor it could be dangerous. A tubeaxle fan usually has a belt drive with the motor outside the air flow. There is no contact with volatile solvents to motor or arc sources. I have seen these used though and have personally used a couple KMart breezebox $15.00 fans in a pinch but extreme care is necessary. aloha, mike
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