How to Build a Small Parts Spray Booth
Frugality is the watchword here at the Second Chance Garage, and that's a good thing. In its proper context, being frugal doesn't mean miserly or cheap, but the efficient use of resources in every way. Doing so leaves the maximum amount of money left over for our projects, and what could be wrong with having spare money?
With that idea in mind we thought we'd show you how to create a small paint booth for your workshop, a booth that not only will keep paint spray (and powder coating dust) away from your equipment, but also will vent most of the solvent fumes out of the space. Such a booth can be used safely inside your house without stinking things up, so you can paint or powder coat stuff in bad weather when you can't — or won't — be outside in the garage. In addition, this is a booth that will "disappear" when not in use so it doesn't take up valuable work space. How 'bout that?
The materials you will need for this project include two (or three) vinyl window shades that are 48 inches wide or wider. Old ones will do, but new shades only cost about $10 each at home stores or Wal Mart. You want these shades to be the retractable type, of course. Next, you need an electric cooling fan* from some wrecked car. Go to a junkyard and pull one off a car. You should be able to buy it for $5-$10. You'll also need some 4-inch dryer duct, preferably the aluminum "accordion-type", but vinyl will do. Buy a dryer "kit" that includes the outside vent and assorted clamps. Lastly, you need your battery charger, some thin scrap plywood, duct tape, cardboard, aluminum flashing and some fuzzy weatherstripping (or a piece of window channel, like we used).
You can use a standard electric fan, of course, but you need to get one that moves at least 600 cubic feet of air per minute. The automotive electric fan moves lots of air and can be run on the charger's 6-volt setting if a lower rpm is desired.
Our paint booth is close to the outside wall of our workshop, next to a small air compressor and the electric distribution box (items that we don't want to cover with paint spray). There's a window nearby, where we vent the fumes and dust. We created a fan "housing" inside two of the ceiling joists. The housing is a combination of thick cardboard and aluminum flashing, shaped to direct the air from the fan to a 4-inch outlet at one end. Inside the housing, its top is slanted upwards toward the outlet to channel exhaust air in that direction. (The joists themselves can be used as the sides of the housing, of course.)
This photo shows the fan mounted to the ceiling joists. The tape around the outside diameter of the fan prevents cavitation at the ends of the fan blades from blowing back into the room. The fan't output needs to be directed efficiently into the vent tube. Experimentation yields the perfect setup.
The outlet of the fan housing consists of some aluminum flashing that has been shaped into a 4-inch cylinder in order to connect to the vent hose. That connection is interrupted by a "weather gate" that is made up of some window channel that is bent into a "U", into which slides a thin piece of plywood. The purpose of the weather gate is to prevent outside air from coming in during cold winter or humid summer days. Sliding the plywood "door" down opens up the vent.
This photo shows the weather gate and the connection to the vent tubing.
Once the fan housing and tubing arrangements are done you simply need to duct everything to the outside, using the dryer kit. Next you need to mount the window shades on the ceiling, arranging them at to create a "wall" around the vent fan. Two shades will create a 90-degree wall, three will create a little "painting closet" in which you can move around. We've found that two long shades are enough for most projects and provide the greatest amount of maneuvering room. Pull the shades down and you have a booth, let them back up and they are completely out of the way.
To use our disappearing paint booth, merely pull down the blinds, turn on the fan, and spray.
We have our booth area at one end of the shop, but smaller setups can be made directly over your workbench or in any other area of your shop. You are only limited by how far you need to duct the exhaust and where windows might be located.
The total cost of our project was $23.00. It's not pretty, but it works very well and is completely out of the way when we don't need it.