Here's a somewhat of a step by step. I'll try and make it as clear as possible.
buy a small compressor used or new (I bought a 3 gal for $40 on craigslist)
take off the cover and motor. note where the hot wire(black) goes, neutral(white) and green(ground) go and mark with a sharpie or make a sketch.
determine which wires on the refrig motor are hot and neutral. I did this before taking all the fans, thermostat, etc off the motor. I also used a multimeter to confirm this. I can give specifics on checking this for the electrically challenged.
I kept the metal tray the comp is mounted on and used that for my build. its better than the plastic POS that you get with the tank.
drill holes where necessary in the metal plate so you can mount it to the tank. use the same screws that held the plastic one in place.
Starting from the outlet cord: black wire(hot) to on/off switch, red wire from on/off switch to pressure switch, black wire w/white stripe to compressor. White(neutral) from outlet cord directly to compressor.
I put a filter between the comp and tank because there seemed to be either moisture, oil or freon coming out of the comp. when I ran it a bit. I use the 1/4" copper tubing already attached to the comp. w/ a compression fitting to attach the filter. I also used the rubber hose w/ a hose barb fitting to run from the filter to the tank. I used the existing check valve which is 1/8"npt. You may need an adapter fitting depending on how you attach the hose. You'll also notice in my pic, I used part of the original plastic cover. The on/off switch is made to clip in this cover, so I cut the plastic cover to fit the area between the comp. and gages w/ a jig saw and attached it with one of the screws in the existing screw holes. I added that red shut off valve which is a 3/8" gas ball valve w/ adapters to reduce it to 1/4" so I can shut off the air without turning down the regulator. If any of this is not clear, let me know, I'll try and explain further.
Using an existing compressor to Mcgyver this thing was much easier for me because you avoid all the welding and most of the parts you need are already there.
