bassin dave,
I finally figured out where the video was, and watched it.
That booth is slick as snot!
The guy said he used a 1000cfm furnace blower, and two 4"/4' long spiral ducts so that enough air was being moved to insure that the airstream was diluted far below the explosion level.
He certainly sounds like he has done his homework, and putting that video online makes him responsible if someone copies him and has a problem, so I don't think he was "blowing smoke" when he said it was safe.
While I don't know what the safe level is, his basic point is to have way more air flow than you need just to catch overspray, in order to insure that there's no danger of a solvent buildup.
I'm not sure you can go smaller than what he made and achieve that.
If you're painting water based paints, you can use a couple of box fans, with washable hvac filters in front of them, set at right angles behind your work piece, like Downriver (I think) uses. That will more than catch the overspray. And you can wash the filters in hot water and soap periodically to remove the dried airbrush paint.
If you're using solvent based paints with that setup, there might be a danger that the overspray will build up on the filters and become a problem. At a minimum, you would have to use disposable air filers, and there is still the posibility it could be dangerous, due to the open motor design of the box fan. But it's not a sealed system, so there would probably be enough dilution of the fumes to make it safe. However, it doesn't remove the dangerous-to-breat fumes from the air, so that system, if used with solvent based paints, should be used in an open garage or shop, with the fans near the door blowing out.
In view of the liability issue, that homeowners or renters insurance won't cover a fire that results from a home built system that isn't UL approved, I'd think twice about any sealed system in my basement or garage.
I use two 1000cfm fans in my garage sawdust collector system, because sawdust is heavy, and it takes a lot of air speed to move it up 8' and over 20' he blower/collector location. These fans were designed to move air through a 10" diameter duct, so two of them drawing air from an 8" pipe that reduces down to 4" at each of my locations means a lot higher air speed, which I need.
If I were following his advice to build a paint booth, I'd only use one, and have the two 4' sections of 4" duct to actually allow the suspended paint particle to precipitate out in the duct on the way to the fan. That's the opposite of what I wanted for my dust collector, which needed to keep the sawdust in suspension until it reached the collector, a 30 gallon plastic trash can below my fan/filter assembly.
Quote:
Originally Posted by bassin dave
what size blower motor or how many cfm's do i need to make a smaller version of the paint booth found in the video clip "building a spray booth for painting fish carvings"?Same concept and design just smaller.
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