I have decided to buy an airbrush and compressor, but I am hung up on the issue of a spray booth. I am torn between buying a commercially available spray booth or building my own.
A decent commercially available spray booth starts at about $135 and up. I would like to build one for under $100. The main issue seems to be the exhaust fan. What size should it be? How powerful should it be? Lots of technical data about CFMs, etc.
What do others do for a spray booth? I welcome all suggestions and advice.
I made my spray booth using part of an old end table, some left-over sheets of Masonite, and some “L”-shaped aluminum left-overs from installing a drop ceiling in the basement…
…the picture above shows it in my basement workshop, but I later moved it into a very small custom-built room in our 180 year old garage.
I added a turntable, cut from some 3/4" plywood, supposedly meant for painting items, but have never needed to use it…I simply hold the item to be painted, either wearing a nitrile glove over one hand, or stick a piece of wood into the body shell of the item being painted.
The plastic vent pipe has been replaced with metal furnace pipe, and I used spun fibreglass furnace filters, cut-to-size, and slipped into wooden tracks in the roof of the spray booth.
Directly above the filter is a small fan, swiped from an old air-hockey game - it vents the fumes from the sprayed paint directly outdoors, while the excess paint is caught in the filter material.
The spray booth has been in use for almost 40 years.
When airbrushing, I always wear a two-stage respirator, which prevents inhalation of both the sprayed particals and the fumes from the various types of paint.
With the respirator properly worn, you could probably dump a gallon of lacquer thinner and not even smell it. I’d suggest that a two-stage respirator be on your shopping listm, regardless of the types of paint that you use.
I use an old residential kitchen exhaust hood for my spray booth. I laid it on it’s back, mounted it to an old workbench, inverted the motor/fan blades to give me more working room inside the booth, and use cheap 12"x12" filters to capture the overspray before it reaches the motor. I do my spraying in the garage and mainly use acrylics, so odor isn’t an issue.
I think the cfm rating would also depend on the length of run for the exhaust. The location (inside the house/in the garage) would be a consideration for the size of cfm. If your spraying lacquers/enamels, the fan should be intrinsically safe as to not create a spark or fire hazard.
If I were to build another spray booth, I would use a squirrel cage fan blower.
Another consideration is lighting. For me, I need LOTS of light while airbrushing, I want the best visiblity to see exactly how it’s being applied.
I took one of those clear plastic storage boxes cut a hole in the bottom. And mounted a squirrel cage fan. I got that off eBay for 50. The box was damaged. Only damage to the unit was a bent flange. A little large at 450cfm. But has a hi low feature. That vents into a hazmat carbon filter. For the rare times I use solvents. Works well. And space for the large scale in there
Here’s a photo of mine, built from plans in the January, 1988 MR. Article was called the Paint Shop Spray Booth by Andy Sperandeo. Had all the information you need.
Rattle cans, a cardboard box, and wait for a nice day works for me. I just don’t do enough painting that it would be worth it to invest in an airbrush. Retired, so there’s no time pressure. And there are always plenty of other projects.
Cfm cubic feet per minute. It is the rating measure of the ability of any air moving device. In a spray booth, you want enough air moving to pull 5rough the filter so the booths purpose is fulfilled. The cfm rating of 5e blower thought completely depends on the booth size. Smaller booth, smaller blower. Maybe somebody here remembers the formula for figuring that out based on the volume of the booth. My booth is large because I do large scale at times. Your target will most likely be 150 to 200cfm. Either by a squirrel cage blower or induction motor type. So you don’t have the fire risk. Other motors have spark producing elements and have 5e motor mounted in the air stream. Something to keep in mind
Brand new member here, and basically a brand new model railroader as it’s been 35 years since my last and previously only layout.
My other modeling interest is scale plastic race cars. Currently I have 3 Grex air brushes each dedicated to a specific task. I also have a spray booth purchased years ago on ebay which seems to be one of the most popular units sold. I’ve never until just now heard of any issues with combustion of flamable paint due to sparks from the fan motor. Is this issue geared more towards a home made unit rather then a commercial one?
Hi, Mike. Good to hear from you. Yep, this will be my first time working with an airbrush. I have always brushed paint on structures and used rattle cans on styrene and foam board sheets.
I would want a paint booth with an external blower motor. If you are using flamable vapor paint, cleaner or paint remover or non-flamable vapor paint you would not want the paint mist and vapors passing over/through the motor. Motor brushes ware and make sparks, sparks and flamable vapor make for an exciting time at the least.
It is also easier to clean the paint residue off the squirrel cage only then the squirrel cage and the motor.
I can say that I don’t recall hearing of anybody that blew off their exhaust pipe.
My home made all sheet metal spray booth with an external blower motor may very well be over 30 years old. A lot of air and flamable Floquil and other brands of paint went through that blower wheel.
Heck, one time even a chipmunk came down the exaust vent, past the blower wheel and chewed
I built my own spray booth mostly out of stuff I had laying around the garage.
I used:
a 16" square 3 speed box fan,
16" x 16" fibre furnace filters,
scrap 1/2" plywood,
a small LED light bar,
a power bar (optional),
a pressure regulator with gauge (optional),
various hose fittings,
The shape of the booth looks fancy but it was dictated more by the size of the plywood scraps than function.
The pressure regulator and gauge are there for convenience. They are not necessary. They just save me from having to walk to the compressor to make fine adjustments.
The power bar allows the fan and the light to be shut off all at once. You could also plug a small compressor into it.
The filters clog up very quickly so they have to changed on a regular basis. To test how clooged the filters are, turn the fan on and then pull the filter away from the fan. If the fan speed increases noticeably then the filter needs to be replaced regardless of whether it looks clogged or not.
Suitable fans can be purchased on eBay for peanuts. Here is one example. This one is 16" x 16". It doesn’t mention whether or not it is a brushless motor (i.e. no sparks) but IMHO you would have to be putting a lot of overspray into the air before there is a risk of explosion. That is highly unlikely when painting models (let the debate begin!![(-D][(-D][(-D]) Just make sure that the area is well ventilated:
I first learned of them when I started my job in a steel mill. The respirator is equipped with elasticised straps to hold the face-portion tight against the face, so there’s no chance of fumes getting past the mask.
The term two-stage refers to the fact that the filter cannisters, which screw onto the mask, will prevent both particulate matter, and fumes from the paint, from entering your lungs.
Here’s a picture, luckily without the mask on my face…didn’t want to scare anybody…
When I’m airbrushing, there’s no smell of paint or thinners and no paint-dust residue on the hairs in my nose, either.
In a steel mill, the filter cannisters often needed to be changed daily, and sometimes several times a day.
When using a ventilated spray booth, the filter cannisters can last for months or even years.
The mask and cannisters should be available at any outlet offering safety gear.
It’s always puzzled me why many spray booths have the filter screens and vent ducts at the back of the spray booth, directly in the path of the sprayed paint. Seems to me that you’d have to be changing the filters every time you painted an item.
I’ve painted over 40 freight cars in a session and in some cases, did similar work daily for a couple of weeks, before the top-mounted filter needed to be changed. Sure, there’s lots of overspray on the back of the booth, but it’s stuck there for good, and not hurting anything.
Thanks for that post. I am planning to use an inline duct fan with a brushless motor. I am not sure if that qualifies as an “external blower motor”, but it is advertised as sparkless and safe from combustible fumes.
