Advice on "Pseudo" Spray booth

[David Huston]

I am trying to cut down on the overspray dust that gets all over my kids stuff when I spray in the garage. I have canvas drop cloths that I hang around the garage door tracks to create a "spray room" of canvas walls which takes up about half the garage. The problem is that there is no roof to the spray room. I am spraying with a Fuji HVLP so it isnt a ton of overspray but seems that a fine layer of dust covers everything. My thought is to get three 20 inch box fans and build a box for them that can go under one of the garage doors and then lower the door onto it for a good seal. I would cover the fans with some cheap ac filters so i dont just move the dust outside. Anyone think this might help? The specs on the box fan say it is 1710 CFM each and the garage is 25x25x10. I usually spray within a few feet of where the fans would be. Any thoughts are greatly appreciated.

[John TenEyck]

Your plan might work, but forget the filters, they will just clog up. Who cares if you blow a little white dust outside. As long as you are using WB products the over spray won't stick to anything and there's no risk of explosion as it goes through the fans/motors. However, it would be a really, really bad idea to use this approach with solvent based products. If your numbers are right, 3 of those fans will exhaust your "spray booth" (1/2 the garage) in about 0.6 minutes, which is pretty good. If you limit the area of the opening on the inlet side to something around 50 Ft^2, the velocity through the booth will be 100 ft/min which should be sufficient to carry away the over spray.

John

[David Huston]

Only spraying WB. The problem is that I cant limit the opening of "spray room" as there isnt a roof to that area just canvas drop cloths hung from the ceiling. That being said, there is a door to the outside of the garage that I can open if that will help. I know that I am not going to get the best conditions in this situation just trying to limit the dust a little. Thanks for the thoughts so far.

[Steve Kohn]

I've done exactly what you are describing with some differences. My approach has worked very well for me. I've screened off around the garage door except I've been using 6 mil plastic sheeting. I also put a piece of plastic to prevent overspray from hitting the partially open garage door. I have a Jet air filter directly behind the open end of the "booth" blowing filtered air into the booth. However the major difference is the fans. I went out and bought 3 of the low profile window fans at Menards. These are the type that each fan has 2 small fan motors pushing air out. I then enclosed them in a 12X24 plywood box and put a cheapo furnace filter in front of the window fans. I line up the 3 boxes with the 6 fans under the rubber seal on the bottom of the garage door and close the door on these fan boxes. I fill the rest of the opening with other plywood blank boxes.

With the bottom of the garage door up a foot off the floor and the fans pushing air out it creates a negative pressure at the small gap at the top of the door. The air entering across this top gap is pulled down along the garage door and back out the fans. The Jet air filter helps keep the volume of air against the door and going down. I liken it to a laminar air flow that does a very good job of exhausting overspray. It really does look very well.

I've posted this approach on this forum before. Just search for my name.

Best of luck.

[John TenEyck]

If you hang plastic sheeting all the way to the ceiling you will have eliminated most air flow into your "booth" except where you want it. That's what I do in my basement shop and it works well.

John

[Bill Neely]

I used to hang plastic sheeting from pvc pipe and greenhouse clips; recently I bought some Zipwall kits - works better and is much faster to put up and take down. If there is any way you can get a small attic fan installed over your door they really move the air out.