Using decommissioned household appliances to create a useful tool is a great way to save money and give a second life to the unit. A homemade compressor from a refrigerator is a classic example upcycling in a workshop, allowing you to get a device for painting, blowing or working with pneumatic tools for pennies. Unlike cheap Chinese analogues, Soviet motors have a high reliability life and are able to operate for years with proper maintenance.
The main advantage of this solution lies in the design itself compressor, which was originally designed for long-term operation in a closed circuit. However, by converting the system to an open one, we get a source of compressed air with low noise and vibration levels. It is important to understand that the performance of such a unit is lower than that of industrial models, but for garage needs it is quite sufficient.
Before proceeding with disassembly, it is necessary to assess the condition of the donor. If the refrigerator has stopped cooling due to a freon leak, but the motor hums and starts, this is an ideal candidate. In the case when the compressor burns out or jams, the project loses its meaning, since searching and replacing the engine can be more expensive than purchasing a ready-made solution. Next, we will analyze all the stages of creating the device.
Necessary materials and tools for assembly
For the successful implementation of the project, you will need not only the compressor unit itself, but also a number of additional components. The basis of the design is receiver, which will accumulate air and stabilize the pressure. As a container, you can use an old fire extinguisher, a gas cylinder, or even the body of the refrigerator itself, if it is metal and sealed.
In addition to the container, you will need accessories for piping: a pressure gauge to control the pressure, a reducer to adjust the output flow and a safety valve. Without safety valve operation of a homemade device is extremely dangerous, since excess pressure can rupture the receiver.
- 🛠️ Main unit: compressor from the refrigerator (power from 100 to 200 W).
- ⚙️ Capacity: metal cylinder with a volume of 10-50 liters (fire extinguisher, propane cylinder).
- 🔌 Electrics: wire with plug, switch, start relay (if the standard one is not used).
- 🔩 Accessories: hoses, clamps, adapters, tees, oil-water separator.
Pay special attention to the tools. You will need wrenches to tighten the connections, a drill or welder to prepare the receiver, and sealant for the threaded connections. The use of high-quality sealant (for example, anaerobic) is critical to prevent air leaks at the joints.
Preparation of the compressor unit and dismantling
The first stage of work is removing the compressor from the refrigerator body. Carefully saw off or bite off the copper tubes coming from the motor, leaving “tails” 5-10 cm long. This is necessary for subsequent connection of the hoses. Be careful: oil may remain inside the system, so carry out work in a well-ventilated area and wear gloves.
⚠️ Attention: Before starting work, be sure to remove all freon from the system. Although the amount of refrigerant in older refrigerators is small, it is not recommended to release the refrigerant indoors. It is best to carefully file the tube furthest from the motor and allow the gas to escape.
After removing the motor, it is necessary to determine the air inlet and outlet. Unlike factory compressors, there are no markings. Connect the power briefly and place your finger near the tubes: where the air is blown out is the outlet, and where the air is sucked in is the inlet. Typically, the input tube is located closer to the center of the housing or has a smaller diameter.
It is better to leave the standard starting relay in place if it is working properly. It ensures correct engine starting and overload protection. If the relay is removed, it will have to be re-selected for a specific motor model, which can be difficult without markings. Check the condition of the contacts and the integrity of the windings before installing on a new frame.
Manufacture and preparation of the receiver
The receiver is the heart of your system, acting as a buffer. The most affordable and safe option is to use decommissioned fire extinguisher volume of 10-50 liters. The metal of such cylinders is designed for high pressure, which provides the necessary margin of safety. Before use, make sure that the container is empty and has no signs of corrosion.
The process of preparing the container requires thorough cleaning. There could be powder inside the fire extinguisher, which, if it gets into the compressor, will instantly disable it. Rinse the container with water several times, dry it and coat the inner walls with an anti-corrosion compound, if possible. For home-made installations, this extends the service life.
It is necessary to drill holes in the receiver body to install fittings. The minimum set includes: an air inlet, an outlet to the consumer, a hole for a pressure gauge and a hole for draining condensate. Threaded connections are best made using welded bosses or high-quality adapters with epoxy glue if welding is not available.
| Component | Material | Function | Installation requirements |
|---|---|---|---|
| Receiver | Steel (fire extinguisher/cylinder) | Air accumulation and cooling | Vertical arrangement, drain at the bottom |
| Pressure gauge | Metal/Plastic | Pressure control in the system | At the top of the receiver |
| Safety valve | Brass/Steel | Emergency reset pressure | Directly into the body of the receiver |
| Drain valve | Brass | Removal of condensate and oil | At the lowest point of the container |
Assembling the system and connecting the electrics
Assembling the pneumatic part begins with installing the compressor on the frame. The motor will vibrate, so use rubber pads or springs to secure it to the base. Connect the compressor output to the receiver input through a check valve. Check valve will not allow air to go back into the compressor after it stops, which will prevent the engine from spinning in the opposite direction and burning out the windings.
The electrical circuit remains almost standard: phase and zero go to the relay, from the relay to the motor windings. If you are using a standard refrigerator relay, simply connect it to the plug. For convenience, you can add a start button or a circuit breaker that will break the circuit when a certain pressure is reached (this will require a pressure switch).
☑️ Checking the electrical part
When installing electrical equipment, follow safety rules. All connections must be securely insulated and the compressor itself must be grounded. Vibration can weaken contacts over time, so use spring- or screw-type terminal blocks and check them periodically. Do not forget that you are working with a voltage of 220 Volts.
Setting the pressure and testing the system
After assembling the entire structure, the moment of truth comes - the first turn on. Before starting, open the outlet valve so that the compressor operates under vacuum and listen to it. There should be no extraneous knocks. Then close the outlet and watch the pressure gauge. The pressure should increase smoothly.
The optimal working pressure for domestic needs is 6-8 atmospheres. Soviet refrigeration compressors can pump up to 15-20 atmospheres, but for painting or blowing this is excessive and dangerous for the hoses. Adjust the reducer at the receiver output to the desired value. If the pressure rises too slowly, check the system for leaks using a soap solution.
The secret of quiet operation
To reduce noise at the compressor inlet, you can install a car air filter. It not only muffles the suction sound, but also protects the piston group from dust, which significantly prolongs the life of the unit.
⚠️ Attention: During operation, the compressor heats up. The case temperature can reach 60-80 degrees Celsius. Do not touch metal parts during operation and ensure good ventilation around the motor.
Maintenance and safety precautions
A homemade compressor requires regular maintenance. The main problem with such systems is condensation. The moisture contained in the air settles on the walls of the receiver and mixes with the oil, forming an aggressive emulsion. Draining the condensate This must be done after each use by opening the bottom tap.
Also monitor the oil level. Unlike oil-free compressors, refrigeration units operate in an oil bath. Over time, oil can be carried into the system along with air. If you notice that oil drops are flying from the outlet pipe, install an additional oil-water separator in front of the tool.
Regularly check the integrity of the hoses and the reliability of the fasteners. Rubber dries out and cracks over time. Replacing the hose is inexpensive, but rupture under pressure can cause personal injury or property damage. Store the compressor in a dry place to avoid corrosion of external elements.
Can this compressor be used for airbrushing?
Yes, you can, but only if you install a high-quality one gearbox and fine filter. The pressure for airbrushing needs to be very low (0.5-2 atmospheres), and the air must be absolutely dry and without oil, otherwise the paint will show defects.
How long can a compressor work without interruption?
Although refrigeration motors are designed for a cycle of operation, in compressor mode they heat up more. Recommended operating mode: 15-20 minutes of work, 10 minutes of rest. During continuous operation, monitor the temperature of the case.
Is it necessary to change the oil in the compressor?
The oil in sealed refrigerator cases is not changed. It is designed to last a lifetime. If the compressor begins to “spit” oil, this means that the piston group has worn out or the oil has foamed due to moisture ingress. In this case, it is easier to replace the unit.
What is the maximum size of the receiver that can be used?
The size of the receiver affects the operating time of the tool before turning on the motor, but not the maximum pressure. For a garage, 20-50 liters are optimal. A larger volume will take up a lot of space, and a small volume will cause the motor to turn on too often, which is harmful for the start relay.