Building a spray booth

Old saying No. 1: "There are old pilots. There are bold pilots. There are very few old, bold pilots."

Old saying No. 2: "There are old modelers. There are bold modelers. There are very few old, bold modelers."

No doubt, you get my drift.

How much are your lungs, liver, kidneys, and brain worth to you? They're worth a cardboard box? More?

I believe that yes, if this hobby is important to you and you want to be both successful and healthy at it, you'll want a good ventilation solution for your airbrushing.

It doesn't take much to ensure your health and that of your family.  Even if it is just moving your airbrush station in front of a window and opening that window.  If in a garage, make sure that you are circulating the air and that you are getting a fresh supply from an open window or open door.

Your post also suggests that you plan to use spray cans.  Be aware that the propellants and can methods are going to put a lot more harmful chemicals into your breathing space than a normal airbrush operation.  So if this is your plan, I would double my recommendation for good ventilation, and stress that you should get a respirator.

To answer your question, yes, you can build a spray booth that is affordable and safe.

What you'll need is a large cardboard box, a filter and a box fan that is rated for moving a large CFM of air.  Fans have their motors in housings, so they aren't exposed to the chemicals and solvents (which is what causes things to go kablooie).

Generally, you'll want to use a box that is 25"x25"x25" (more or less).  Cut the top flaps off of the box.  This will be the front of your booth.  At the opposite side (bottom of the box) cut a hole the size of the box fan (or whatever fan you end up using).  Put your filter inside the box, in front of the fan cutout.  If your work area doesn't vent directly out the garage door or through a window, you'll need some dryer tube that can be secured to the fan with zip-ties.  You should look for the 6" or 8" diameter tubing.  You can cut a hole in the top of the box and put a light up there so you can see, or you can get a small battery powered light and try to mount it in the box itself.

For a box this size, you'll need a fan that can move about 435 CFM at a minimum.  If you have a box with different dimensions, use this formula: ( (width in inches x height in inches x 100) / 144 ).

-Fred

Gigatron wrote:

Fans have their motors in housings, so they aren't exposed to the chemicals and solvents

Since when? The fan motor, like all electrical motors, generates heat. That heat needs to be disappated, which is why all large electrical motors are piercd by numerous ventilation holes. The air  flow from the fan  cools  the motor, at least in every breeze-box type  fan I've ever seen.  Furthermore,  I have never seen such a fan with a shaded pole motor. There are two sources of potential ignition in an electrical fan. One is the carbon brushes that conduct current to the armature. The other is static electricity, which can be substantial in dry winter conditions.

No spray booth used for flammable aerosols should be constructed of a combustable material, especially a flimsy one that will not only burn, but will do nothing to contain a fire or explosion.

There are a lot of things that one can do and get away with. These are usually the same things that, when one does not get away with them, result in saying things like: "How could I be so dumb!" and "I wish I had______!" Or worst of all, something like: "so what if I smoked two packs a day, it's not my fault I got emphysema and cancer!"

Whatever you do, DO NOT build your booth from cardboard!

This is probably illegal; I'm crossposting (SSSHHH!!) portions of the response I just wrote to Gigatron (Fred).

Spray booths are constructed for two reasons: to control inhalation exposures, and to prevent fires.  In order to do the latter, spray booths are designed, constructed, and expected to perform as a system, not just individual components thrown together with the hope and prayer that a failure with one component will not affect any other.  All the hazards of a system have to be identified and controlled, including those inherent with the system itself, and those that impact upon it.  If they are not controlled, and the system fails, then the potential for catastrophic results is greater than if the system fails together as a complete, properly designed system.  If a booth is cobbled together without thought to the hazards, then the potential for loss is greatly increased and includes loss of the system itself and everything that is directly or indirectly responsible for its operation, even the human element.

Cardboard burns. Period. It doesn't matter if it's flammable or combustible.  Couple that with a range hood, bathroom, or other similar fan, and the hazard potential (or risk) increases exponentially. And as an anticlimactic statement, it also does not provide adequate structural rigidity or integrity.  Your system fails. Completely.

I've only seen a couple spray booth fires in my career, and I can state emphatically that I'm glad they were designed and constructed correctly.  The fires were contained and extinguished quickly, with no appreciable losses noted.

I've said this once or twice before, but if you want to build a spraybooth, do it the right way the first time.  Make it a point to learn to not be satisfied with a toy...

Gip

Thanks for jumping in Gip!  And at least as far as I'm concerned, (not that my opinion necessarily means anything to the administrators) the area of safety should be immune to any rule that limits repetition!

Folks, I've been in a structural fire. (No, it wasn't started in a spray booth.) Ever wondered why they are called firefighters? Because it's a lot like combat—only scarier and more dangerous. Please! Listen to the voices of experience!

Ryan, there are numerous threads on this subject in the forums. Gip has even gone through the calculations.

Basically, you want a squirrel cage blower with the motor mounted outside the air flow, and a sufficient cubic feet per minute (cfm) rating. That's the easiest and safest way to go.