Make an Air Compressor from an Old Refrigerator
Described here is a quiet air compressor with plenty of power to inflate tires, blow dry parts and even spray automotive paint. All that's needed is a 110volt refrigerator or freezer (bigger is better) with a salvageable compressor and an air tank, with an air gauge, safety release valve, few feet of 3/8 I.D. air hose and some fittings
Contents
Steps
- It is extremely important to properly evacuate all refrigerant from your donor refrigerator's system. Many shops will do this free (and add it to their inventory.) This is also a good time to make sure the compressor is working
- Once all the gas is out of the system, cut the copper tubes. There's one going in and one going out of the sealed compressor module. Use a tubing cutter for the job. When cutting, leave as much length of copper tubing as possible with compressor. Try not to turn the unit upside down.
- Follow power cord into the wiring harness tracing the wires to their separate terminals on the capacitor. Mark both wires and terminals with masking tape or a marking pen to keep their proper configuration. Make note of wires at this location that will go to another set of terminals on 110v sealed compressor module (or "pump"), tape and mark these wires and terminals as well.
- Remove the wiring to everything else except the capacitor and pump. Connect corresponding power cord wires to the capacitor and green ground wire to base of pump.
- Gently bend both copper lines on the pump to point vertically, while being careful not to kink them. Make sure pump unit is secured to prevent "lurching" or pulling wires loose by "walking" from vibration.
- Move pump away from walls and ceilings and clear an area of at least {{safesubst:#invoke:convert|convert}} in circumference. Plug it in and listen for motor sound: If the unit does not run, unplug it at once and check power cord wires. Note, one copper tube may spit oil at first. This is normal, but stand clear and mark the spitter as the supply line.
- If no oil blows out as unit is running, put a finger tip on the end of the copper lines and feel for a gentle vacuum. The line without a vacuum should be marked as the supply line.
- Attach the supply line with a short length of air hose and clamps to a 1/4" npt fitting connected to a 4 way "tee" with the following; a 150 lbs safety release valve, a 120 lbs or higher air gauge in line to 3 way "tee" in line with a {{safesubst:#invoke:convert|convert}} or larger steel air tank. On one leg of the second 3 way "tee" install a female "quick connect" Air chuck for the hose to inflate your tires and your air tools.
- Using the original rubber mounts and level as possible, bolt the pump to a sturdy utility cart or any frame you like mount the air tank as close as possible to the pump. Clean up and insulate all wiring, route air fittings to the gauge, safety valve and quick connect assembly.
Tips
- It will take approximately 2 minutes to build 80 lbs pressure in a {{safesubst:#invoke:convert|convert}} air tank.
- You will need a pressure switch with an unloader and the check valve needs an unloader port in it. Your air tank has to drain completely before the compressor will come back on.
- With a compression fitting and a high pressure female coupler, pressures in excess of 800 psi have been generated.
- An automatic air pressure shut off switch and regulator can be salvaged from a worn out store bought compressor rig and really is a great refinement.
- A 110v compressor of this type, set up as described can give thousands of hours of service as long you don't turn it upside down or let the oil get pumped out by a supply line being lower than the pump.
- Running a compressor without a pressure switch is foolish and unsafe.
Warnings
- Do not operate any air compressor without a safety release valve.
