DIY Silent Air Compressor

This article is posted on behalf of Adam and details how he built his silent aircompressor.

After getting tired of not being able to airbrush at night due to a very noisy compressor I set off on a task to build a nearly silent one. I built this compressor about two years ago.

Here is a list of the major parts I used in building my compressor.

Refrigerator compressor (I salvaged mine from a mini fridge that wouldn’t stay cold) (left)

A pressure regulator (110Psi was more than enough for hobby painting) (left)

Pressure cut off switch  (left)

Air Tank (left)

If you are salvaging a compressor from a refrigerator, It is extremely important to properly evacuate all refrigerant from your donor refrigerator's system. Many shops will do this for free.

Cut the two copper tubes coming from the sealed compressor, Make sure to leave as much of the tube as possible. Once cut, avoid turning the unit upside down. Or the oil will spill out.

Follow the 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. Remove the compressor for the donor refrigerator. Save the rubber feet, they will help reduce noise and vibration when you mount the compressor to its new frame. 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. This will help keep the oil from spitting out or making its way down your feed line into your pressure vessel once it’s attached. Make sure the compressor is secured to prevent "lurching" or pulling wires loose from vibrations.

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 mark this tube as the supply line.

If no oil blows out as the unit is running, put a finger tip on the end of one of the copper lines and feel for the side blowing air. The line blowing air is the supply line and should be marked as such. 8

Following the diagram below and using the appropriate brass fittings and air hose connect the compressor supply line to a 3 way tee. On one end of the tee you will have your air tank with safety pressure release valve. On the other end connect air hose to a second tee with the Pressure Switch and pressure regulator. Finally, attach a quick disconnect to the pressure regulator.

Follow the wiring diagram for your pressure switch and connect the wires from the compressor as well as a grounded power cord.

For The air compressor intake you should install an air filter.

Or if you’re in a bind a wiffle ball at the end of the copper intake pipe with a coffee filter wrapped around it. This worked for me for the first few weeks.

Using the original rubber mounts and making it as level as possible, bolt the pump to a sturdy frame or base plate. I decided to make a nice wood box that sits over the 10 gallon air tank.

This compressor won't win any awards for its looks, but it's silent, cheap and fun to build. I plan to use what I have learned from this project on my next DIY, a silent vacuum chamber for investing.