This is a mount and switch block to keep the head of an airbrush compressor cool. It uses a fan salvaged from an old computer powered by a 12volt DC "wall wart" transformer. The switch is of the generic type found at any hardware store.
It is quite effective at keeping the head cool as you can see on this video:
The cooler head will help prevent water from condensing inside the line and possibly extend the life of your compressor. Especially the cheap eBay compressors.
I printed this on my Makerbot Mini. The base was printed with 3 shells and 50% fill.
A screw goes down through the top next to the switch and a nut secures the bottom wire cover (See the upside down photo). The head of the screw is epoxied in place and the "FAN" plate is glued ontop to hide it. One photo shows the switch mounted with the screw sticking out. Another photo shows the inside of the wire cover to show a view of the wire strain relief arrangement.
The power wire goes through the notch on the end of the wire cover. The fan wires enter through the side notch.
It attaches and detaches easily from the compressor as shown in the video. The tabs that fit into the compressor fins are made a bit thick so to fit many compressor models. You will need to file / sand them to fit your model. They should fit snug between the head fins but not wedged tight.
Print the base with 3 shells at 50% infill. The settings for the other parts aren't as important.
Sand and/or file the mounting tabs to fit snugly between your compressor fins but not to wedge tightly.