Cheap and Portable Spraybooth by Gareth Phua

The need for a spraybooth for my airbrushing came up when my fiancée commented that the fumes from my Gunze Mr.Color paints were overwhelmingly strong. The fact that my work space was getting a lot dustier than usual due to the paint particles settling after an airbrushing session also spurred me on.

I had limited space and a pretty tight budget so I was contemplating how to best go about building the booth. I then spotted those Japanese plastic containers that are sold in some shops here in Singapore for storage that an idea came to me. I need not build a booth per se, just use one of these boxes as a booth and find a means to extract mainly the fumes and most of the paint particles.

I thus purchased on of these boxes for a princely sum of US$10. It’s advisable to get a sturdier one but with enough flexibility(not too hard, which makes them brittle). I’ll explain why a little later.

The next step was to plan my extraction sequence. Do I mount an extractor fan at the booth or do I run a hose from the booth to the fan? Discussions with my air-conditioner repair guy proved that the fan I wanted to get would best be placed at the end of the exhaust duct. The problem I faced predominantly now, was that the hose was round, whereas the exhaust fan had a square housing. I also needed to find a way to connect the hose to the booth.

My friend, the a/c guy, offered to help me build the adaptors needed to join the hose to both the booth & the exhaust fan. We used off-cuts from aluminum to form the adaptors, since these were available and at the same time, relatively easy to work with.

With that connection problem out of the way, I proceeded to buy the materials needed. The most expensive item was perhaps the exhaust fan. I was recommended this brand KDK, which is pretty common around Singapore. You probably can get something similar in your country. These are bathroom extractor fans that have an RPM of about 1500 and weight about 1.4kg. The fan cost me approximately US$40. I then had to get a flexible 6” diameter aluminum hose but these were only sold in set lengths of 6 metres each. I rounded up a couple of modeling friends and we shared the costs. I offered to pay a little more as I wanted 1.5 metres of the hose. That cost me about US$9.

When my friend passed me the completed joint adaptors, all I needed to do was cut a hole at the bottom of the plastic box. This is where getting one that’s too hard will cause problems. Being too hard, it becomes brittle, and therefore any drilling or cutting would cause major cracks as the plastic flexes. In order to cut the hole, I traced the outline of the adaptor for the booth, which was a square piece with a pipe-like extension riveted onto it. The pipe-like extension, which was almost the same diameter as the hose was used as a template. Next, holes were drilled next to each other all around the circumference of the traced circle, as closely as possible to each other. Remember to use the lowest speed possible for your drill! It was then a simple case of using a sharp pair of shears to cut through the remaining bits. Sure the hole isn’t pretty but the square base of that joint would cover it up. After mating the base to the box from the inside, holes were drilled onto the four corners of the aluminum base and then screws & nuts were used to fasten them properly to the box before duct tape was used to seal it up good.

The exhaust fan end was an aluminum housing which makes my job a lot easier as all I had to do was slip it over the plastic casing of the fan. I could secure it further with duct tape but the fit was so good I didn’t need to.

Click on images below to see larger images

Next I secured the hose to the 2 couplings using either duct tape or metal pipe braces. I chose the latter as it doesn’t cause any damage to the hose should I decide in future to change the box.

Finally, I added a kitchen cooker-hood filter available from any hardware store to the hole at the box’s end. This would serve to trap paint particles and yet allow the fan to extract paint and thinner fumes. The extracted fumes and expelled outside my window, which is why the fan is presently raised to the window level with books.

Then, it was time for the test. I primed one of my Gundam robot model kits(seen here dismantled). The test results were that although paint fumes were not entirely removed, the smell did clear up much faster, about 5-10 minutes after airbrushing. The paint particles so far seemed to fly about a lot less, even with the filter blocking the “entrance” to the fan. I guess this setup will work for me now, but in the future, I might build me a wooden or even aluminum booth. The advantage of this plastic box over a wooden one is versatility and portability. Having limited space, I can easily cart it aside whenever I need the space for building and then bring it back fairly quickly when I need to airbrush.

I hope you found my tip useful should you be too lazy to build an entire booth, like me.