Large Scale Central

DIY Paint hood/booth

So this is a topic that popped up on Cliff’s thread. And since we yet again derailed his poor thread running down yet another rabbit hole, I decided to pose my thoughts and questions here.

So as a dyed in the wool DIYer who would rather make a cheaper, more inferior product at home, than I can buy for no other reason than the satisfaction of doing it (and to save a few bucks) I have pondered many times the need for a paint hood/booth. Int he days of my competition modeling this would have bee a really good idea because back then I used solvent based paints and thinners. Now that I have switched to acrylic its less of a health issue; but, breathing anything like paint can’t be good for you and with airbrushing pushing very fine atomized paint it still blows around and gets in your lungs and all over everything when the dust settles. So a paint booth is a good idea.

And really not an overly complicated thing. I have yet to make mine but I have three ideas for various versions of one that a DIYer can make on the cheap. so as a disclaimer, I can’t tell you any of these ideas will work or be good.

Option #1: The smallest idea I have, is for a very small exhaust hood that will do nothing more than catch paint particle and keep them from spreading all over and into your lungs. Won’t do anything for the smell. A person could fashion a large CPU fan (say 6") to the bottom of a small box that then could hold a coffee filter at the top of the box. This would move the air through the filter and catch the paint particles. It would be small and highly portable and easy to store. Another idea to add a little to this for fume control would be instead of the coffee filter, get the bags that hold activated carbon for the back filter on a fish tank. They have removable and washable filter cloth bags and the carbon replaced. You could build the box so they slide in and out. This would force the fumes through activated carbon and help with odor control.

Option #2: this would be more of a bench top type spray hood. You can go to one of the Big Box Store hardware stores or your local Habitat For Humanity Restore and buy a cheap bathroom exhaust fan. They can be mounted to the underside of a plywood box. They come with a place to connect like a dyer vent hose. This could be route out say a window. Or you could use a furnace filter on the top of the box. Wire in a cord with a plug for portability. This would be a little more permanent but still a cheap simple solution.

Option #3: Along the same lines as Option #2, for a permanent paint booth, I think one of the fancier triple function bathroom fan/light/heater would be great. You could make the hood out of plywood and the sides out of whatever you want so in essence this is still just a hood. Put the fan on the bottom then route a dryer hose out a window or where ever else you can pipe it to, so you can remove the fumes. This should probably be wired with a heavier plug as the heater can draw some amperage. By doing the triple function fan you not only are removing fumes, but you have a light to see by and a heater to aid in drying, especially if you are going to put this someplace like a garage or workshop which may not be at ideal temps. If you are really bold you could put the heater on a thermostat so that it is not on all the time, as it would heat up a little booth way to hot since it is meant to heat a room. An old school mercury wall thermostat would be ideal and easy to wire in. This whole thing would not be very mobile and I likely would build it as a cart and have paint storage underneath. If you make it cart style then it could be unplugged and moved. The under side of your cart could hold your airbrush compressor and piped to a manifold for your dryer and regulator. A single plug could plug the cart in and a heavy duty power strip used inside the cart to plug in the fan and compressor and put a couple of switches in to turn on the various components (light, heater, fan, compressor). This would give a person a killer semi sorta mobile paint station.


I like cliff’s fan from a blowup item …they are out there after say the item gets torn up or ripped… motor for sale on FB etc. …

1 Like

I agree, I thought this was genius, but then Cliff is a genius

1 Like

I made a ghetto box almost exclusively with material I had in the barn:

The sides are 1/4" melamine coated fiberboard, the white surface reflects light nicely!
The frame consists of various chunks of 2x4 I had lieing around.

I purchased a 20"x20" furnace filter at the local hardware store and a LED lighting string from Amazon:

Had the 20" box fan kicking around the shop:

It’s ugly and decidedly non-portable, but it does a great job of containing the mess. There’s
no odor control, but I see no sign of any paint particles escaping. Not sure yet what sort of
mileage I’ll get from the filter…


I like the lights idea…

For a spray booth, be very careful of the kind of fan that you use, you can’t just use a cheap exhaust fan if you’re dealing with possibly flammable fumes. There are specialized fans made for spray venting.

1 Like

Steve that is a killer booth. May be made from scraps but it is a down right nice spray booth.

There is a couple of things to keep in mind when building your own paint booth. #1 is safety.

If using water base paints only, this isn’t such a concen but we all once in a while use some enamel or lacquer spray cans. A paint booth should never be built with an in line fan or light because of the possibility of spark ignition. Ideally even the fan assembly in the air stream should be of spark proof material. I know lots of peopole get away with it but some don’t.

The other thing to think about is capture velocity, ideally for partical laden air you need 100 cfm per square foot of face opening. So keeping the opening as Small as possible lets you use a smaller and usually quieter fan.

Also consider pressure loss across the filter bank and the dirtier the filter gets the more loss and less capture of particals being sucked to the filters.

For air brushing you can get away with as little as 50 cfm per foot because of the finer particals and more control of paint application.

Just my 2 cents


That’s a good call Bob.

and I would not have thought of that (obviously). But I could see where open electrical connections could be kind of exciting around flammable solvent based paints. And it wouldn’t be just “bad” connections either as many/most fans have open coils and brushes and you can even see the sparks a sparkin in them. So any fan that draws the fumes over/around/through the motor would be a bad choice. The motor would have to be sealed or separate. Makes me wonder about the bathroom fans and moisture if they are sealed or separate, I will have to look. This is where a squirrel fan like Cliff’s would be a good idea as the motor and squirrel cage are separate.

Rick same comment to you as to Bob, we cross posted. But everything you say makes perfect sense and I am glad you two chimed in before I inadvertently blew myself up. I haven’t made mine yet and now I know what to look at and think about with regard to fans especially the bathroom exhaust fans. I am really curious if they are sealed or not because I think they are a draw through type fan. But don’t know that for sure. I would think that even though explosion isn’t an issue they would not want moisture laden air passing through it. But again I will check

Bathroom fans come in two varieties. One has an open frame motor in the air path. Very bad for this application. Another uses a squirrel cage fan with the motor mounted outside of the air path. While not an explosion proof designed for spray use fan, it is a reasonably safe alternative.

I’ll make the same suggestion here as I did in Cliff’s thread: If you build one large enough to paint a loco or car in, make it so it can be disassembled for storage. The one I made from an old tube type TV box was a fixed size and frequently got in the way. Due to it’s size, and infrequent use it was dissembled and scrapped a few years ago.

1 Like

This has been a big consideration of mine. And one of the reasons it is being Devoned. Part of me wants a break down storeable bench top booth and part of me wants a dedicated cabinet. But how much painting am I really going to do versus the real estate it takes up. Used as a stand alone unit it could be nice if you have the room and could be used to store your paint and be able to roll it around. But I don’t have that real estate. So I think I am going to make mine as you suggest and have my air system be more universal so I can use it for nailing and painting and what not. Good thoughts Jon

Fan issue is definitely something to think about … thanx.

I never had a Spray booth with a fan for exhaust in it… All my painting
was done in the garage with a plain cardboard box to keep the spray from
going everywhere… I bought a cheap lazy susan, placed a board on top of it then a
few pieces of newspaper over it all, the placed the model I wanted to paint on it
and painted it being able to turn it 360 degrees…

That was fine for the railroad cars, but the Colorado Models buildings we painted on a
piece of plywood placed on saw horses and covered with newspaper… These buildings were
painted before assembly…

When we painted in the garage, we’d raise the garage doors a few inches to get some air flow
after we were done painting, letting the paint dry…

1 Like

Speaking of paint booths I have been custom painting models for some 60 years and have used a paint booth for most of that time, but I would like to add here that most of my models O and G gauge are painted out in the open. I say this not that painting with good air flow is not important for both health and dust free models, but painting in a small booth does not have the correct painting room to move and rotate the models for a proper paint job. Most of my models are paint outside with one hand holding the model and the other with air brush, or rattle can in the other, this does two things, giving good light and rotation to see how the paint is flowing on the model. I will say here that dirt in the paint is not a problem and no more then air flowing though a paint booth will get. I will also say that I live in Texas where I can pick good days to paint, warner weather and no wind, I do realize that different parts of the country may not be so lucky for good weather conditions. I would also like to say that good paint jobs are from knowledge of painting and this only comes for time and learning paint skills, not so much from a paint booth which does not make you a better painter of quality model results. Painting your models does require skills, can you look at your models that you are painting and tell what the results will be, do you have too much paint on it, or not enough, I can and this comes for all those years of experience and yes I have made every mistake in painting known to mankind.


I’m with John - rattle cans should be used outdoors. I seldom paint indoors unless it is brush painting acrylics.

Unfortunately I live where I’m lucky to see a high of 40F this time of year :cold_face:
I heat exclusively with wood, the only area in the house that sees 65F is where the box is placed,
about 15’ from the main fireplace.

Devon me boy, those are all great pipe dreams. In order to capture paint particles (over spray) you need an air velocity of 100-150 feet per minute velocity. So lets say you build a booth that is 2 feet high x 3 feet wide, or 6 square feet. To maintain the required velocity you need a fan that will move 6 sq feet times 500 feet per minute velocity or 600 cubic feet per minute, and that will need to be at a minimum of 2" static pressure. Bathroom fans don’t even get close.

The static pressure requirement is to overcome the pressure drop across the filters that will need to be no less square footage then the entrance to the booth. Filters need to be equal to the best filters you would buy for your home for air purification. The filters need to be upstream of the fan and have a reasonable transition from the square shape of the filters to the round shape of the fan inlet (for least pressure drop.

Next the fan needs to be a squirrel cage type fan, preferably a backward curved or radial tip type tip to get the static pressure needed. The backward curved fan will be quieter than the radial tip.

This is a thumb nail description of what is needed for an efficient paint booth or hood. I would recommend doing some research online to see if there is anything available for booth/hood design information. My books are currently packed or I would sketch out a rough design for you. I promise you will not be satisfied with a ‘bathroom fan’ design in the long run. Home made can be cheaper, and sometimes better than store bough if they are done right.

I can’t recall where you live Andy but one of the issues with garage painting is temp. I would miss at least 4 months of painting time. Plus as a wood worker I have way too much dust to contend with. I would love nothing more than to set up a spray booth in my garage not only for my modeling but my wood working also. But between weather and dust that just isn’t a reality.

Unless I can talk the wife into moving and building me a 50 by 100 shop with a upstairs enclosed heated hobby room. . . . :thinking:

1 Like

Now that is a [Bob_Cope] great pipe dream!

1 Like

The open end of my booth is 20" x 47".
The only specs I have for the fan are:

The Lasko 20 in. 3-Speed Box Fan combines the cooling power of 3 fan speeds with the wide-area air flow of 1820 CFM air circulation and a 20 in. fan

So it would appear to have 2x - 3x the necessary air flow, no idea about static pressure…

I have been keeping a close watch on the surrounding area. There is a LOT of over-spray inside the booth, the filter is covered. But there is absolutely no sign of particles either on the fan blade, the area outside the opening, or the area on the discharge side.