Here is my how to on modifying fridge compressors into silent air compressors. They are ideal if you need:
+ a silent compressor
+ a high pressure compressor
+ have little space and/or don't need a typical shop compressor
Typical fridge compressors are 100 - 300 watt units, deliver 0.7 - 1 CFM of air and can reach pressures over 500 psi.
Here is a video where I discuss the process briefly (I'll make a new one soon - feel free to comment or ask questions)
There are two ways to get a fridge compressor you want to turn into an air compressor:
A) buy a salvaged compressor
B) salvage one yourself from an old fridge
In case you choose option B then you have to remove the compressor from the fridge yourself - that process is described in the next step. If you already have a salvaged compressor then go to step 2.