Paint booth exhast

[slant6]

I need some help making a simple a possible exhaust system for my paint booth. I read a post recently about paint fumes igniting and exploding due to the fan used and would really like to avoid that.

Here is my paint booth.

and here's a shot of the window nearby, it still has the old dryer exhaust in it, so I assume I can use that.

Im mostly concerned with not blowing myself up, but also the best/cheapest way to get the fumes out.

[Art Anderson]

Slant6

Best is not always the least expensive, especially where your safety, and that of your house is concerned. You are correct to be concerned about the potential of an explosion and fire here.

A properly set up exhaust system for drawing paint fumes and overspray out of your basement should have an explosion-proof motor that is completely outside the airstream. The best type of blower to to that would be a small squirrel-cage unit, with the motor on one end, the airflow going through the squirrel cage completely away from, indeed blocked from even reaching the motor. The best explosion proof motors are sealed induction motors, which have no commutator or brushes to cause sparking. For example, motors that work like that in your electric drill, a Dremel tool, have brushes on a commutator, and if you look through the cooling vents in a dark room while one is running, you can see the blue flickering light of sparking. But, squirrel cage blowers aren't exactly cheap though, check suppliers such as Grainger for one that will work with 4" ductwork on both inlet and outlet, as that is what a dryer vent diameter is.

Depending on the costs involved, your best bet might well be to just bite the bullet, buy a ready-made model spray booth--that would be a one-time buy, should last for years and years.

Art

[AzTom]

It's amazing how many times this topic comes up. I agree with Art on this one, except for the Explosion Proof motor part as they are designed to operate within the hazardous location. You DO need to have a fan with the motor outside the exhaust fumes. You also may want to use a better lighting system, a broken lamp can cause a serious spark.

Here's the type of fan you want, at 180 CFM. They also sell an adapter for 4" round duct. $82.00

Fan Motor Sale

Here is what my Badger model looks like for mounting ideas.

AzTom

[slant6]

Well, I guess Im not gonna get outa this cheap. I live in a rented house (not that I d wanna burn down one I own either), so I really dont need a fire. I do have a couple more questions, if you guys dont mind. It sounds from the description that the fan should be outside the window, am I right with this assumption, or no? I only bring it up because this is a basement window, and in the winter the snow piles up next to in, and also, being outside, i would need something more or less watertight. As for the lighting, the light you see is a brand new neon light, but it sounds like you think I should be using something else, do you have suggestions for that?

[Doughnut]

No, you don't need to have the fan motor outside the window. You should just have it outside the area where the actual blades of the fan are, like the squirrel-cage motors shown. You don't want to us an old range hood as they suck the paint fumes directly through the fan and motor area. I used a large squirrel-cage motor meant for a hot water heater that I purchased from Axman Surplus for $15 new. It has been great and sucks hard enough that I don't even have over spray in the booth (but not so hard that it moves the model pieces). Since it was not mentioned, make sure you use some sort of filtration between the paint booth and the fan. I use small furnace filters which capture all the paint. You can tell if they are capturing it all when you remove the filter and see if there is any paint on the fan blades. Good luck.

Edited September 8, 2010 by Doughnut