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Old February 21st, 2012, 10:30 PM   #13 (permalink)
teleplayer1000
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Join Date: Feb 2012
Location: San Antonio, Texas
Posts: 79
Quote:
Originally Posted by jeffbos66
All,

I live in northern Alabama and the fluctuations in temperature and humidity makes year around guitar finishing a problem. So.....

I'm building a paint booth in the corner of two walls in one of the rooms (8’X12’) in my shop. The walls are covered with plywood (instead of sheetrock). I was going to encase a 4'X4' area around the spraying area with walls made out of heavy plastic. I'm going to install a filtered fresh air vent and a dehumidifier in the room. I was going to control the winters with an electric heater. The summers, I'm not sure of yet. This room is usually 15 degrees cooler than the outside air temp so I would like to see if just running the dehumidifier will do the trick. I'm installing the heater & dehumidifier outside of the spraying area encased in plastic.

So the questions I have are concerning venting…

One idea based on reading the forums was using 20" box fans with filters mounted to the intake. I would install a sheet of plywood across the corner (forming a triangle with the other two walls) to mount the fans and act as a manifold for the fumes. I was going to use two vertical fans and possibly one overhead fan that will blow the fumes directly into the manifold. I would then vent the fumes out of the shop using dryer ducting. I am aware of the explosion hazard using the fans but I have read where they are safe using household filters on the intake. I’m not convinced a common manifold is safe with all of the fumes blowing around the back of the fans even if I put a filter on both sides of the fan. What are your opinions? Should I run the vent line (dryer vent line) out the top or bottom of the manifold, or does it matter? The fumes seem to naturally rise but with all that air pressure in the manifold seeking an exit point, I wasn't sure it really mattered. Should I encase the manifold with plastic to prevent the fumes from permeating into the plywood?

2. The other idea I read was to pressurize the room with filtered intake air (blown in with a fan) and then a simple exhaust duct venting to the outside. This seems safer but not as effective in exhausting the fumes. Thoughts on this idea?

Thanks
You cant really achieve a positive pressure booth only blowing air in. You would basically have a crossdraft booth at that point. You have to be able to control the air exiting. The only way to do that is with an exhaust fan drawing the air out and both intake air fan and exhaust fan must have baffles you can open and close to adjust air flow to achieve positive pressure. I own a collision center and ive been doing this for 26 years. I have painted cars in garages and got great results. The main causes of trash in paint is to much air movement (ie:turbulence), dirty painter or dirty project. Make sure you are clean, whatever your painting is clean, your air is run through desicant filter and oil and water seperator. Ideally a compressed air dryer (refrigerated air) is the cleanest driest air you can paint with. Also leave your booth on till solvents are finished escaping. Lot of people turn booth off cause overspray is gone but you still have solvents floating around you cant see which will land on your project and give you solvent pop or dye back.
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