Creating high-quality aerographic equipment often comes down to budget, because professional compressors are not cheap. However, every master or home craftsman has the opportunity to save money by turning an old one refrigeration unit into an effective source of compressed air. This homemade product works quieter than its factory counterparts and provides stable pressure necessary for artistic painting or modeling.
The main advantage of the modification is the durability and availability of components. Motor-compressors from household refrigerators are designed for round-the-clock operation for many years, so in periodic use they will last for decades. You do not need to have an engineering education to assemble a working system, just basic skills in working with tools and an understanding of the principles of pneumatics.
In this article we will analyze all the stages of transforming equipment into a professional tool. You will learn what parts will be required in addition to the motor itself, how to correctly calculate the volume of the receiver and why check valve is a critical element of the safety of the entire structure.
Selection and preparation of initial equipment
The basis of the future station will be a motor-compressor removed from the old one refrigerator. Units from Soviet models like ZIL, Biryusa or more modern Atlantare best suited, as they are characterized by high performance and reliability. Before dismantling, make sure that the device is in good working order: when plugged into the network for a short time, it should create a noticeable stream of air and not make grinding sounds.
The extraction process requires care so as not to damage the copper tubes and electrical part. First, you need to cut the copper tubes at a distance of 5-10 cm from the compressor housing, leaving enough length for subsequent connection. It is important not to cut them with a hacksaw, as metal shavings will get inside, which will disable the mechanism.
⚠️ Attention: Before any work with the electrical part, make sure that the device is disconnected from the network. Capacitors can retain charge, so do not touch the contacts with bare hands immediately after switching off.
After removing the unit, it should be cleaned of dust and rust. Use a wire brush to brush the body, but try not to damage the factory paint, which protects the metal from corrosion. If there are deep dents on the body, it is better to straighten them, as they can interfere with tight installation on the frame.
Necessary tools and components
To assemble a full-fledged compressor station, one motor is not enough. You will need to create an air storage and purification system, as well as provide pressure control. The list of required parts may vary depending on the availability of materials, but the basic set remains the same for most projects.
The main element of the accumulation system is receiver. Old 10-liter fire extinguishers, freon cylinders, or even metal cans are often used as it. The main requirement for the container is the ability to withstand pressure of at least 10-15 atmospheres without the risk of rupture.
- 🛠️ Fittings and adapters: will be required to connect all elements of the system, including tees, angles and nipples.
- 🔧 Pressure switch: automates the process, turning on and off the motor when the specified parameters are reached.
- 💧 Moisturizer: critical for airbrushing, since water in the air will ruin the paint.
- 📏 Pressure gauge: necessary for visual monitoring of the pressure in the system.
Also, do not forget about high-pressure hoses and clamps to secure them. To connect to the airbrush, it is better to use a specialized spiral hose that does not get tangled and is of sufficient length for comfortable work.
Manufacture and preparation of the receiver
The receiver acts as a buffer, smoothing out pressure pulsations and allowing the compressor to operate in native mode. If you are using a fire extinguisher, the first step is to make sure there is no corrosion inside. To do this, you can pour water with vinegar inside, shake and drain the solution.
In the upper part of the receiver you need to drill holes for installing fittings. Typically, a minimum of three outlets are required: one for connecting the compressor, a second for the air outlet to the airbrush, and a third for installing a pressure gauge or pressure switch. The threads in the holes must be processed with a tap of the appropriate diameter.
For reliable fastening of all elements, use anaerobic sealant or FUM tape. This will prevent air leaks, which can significantly reduce the efficiency of the entire installation. Pay special attention to the insertion point of the inlet pipe, since there the pressure will be maximum.
Why is the volume of the receiver important?
The larger the volume of the receiver, the less often the compressor will turn on. For airbrushing, the optimal volume is considered to be from 10 to 25 liters. A smaller volume will lead to frequent starts of the motor, which will shorten its life, and too large will take up a lot of space in the workshop.
After installing all fittings, the receiver should be tested for leaks. Connect it to the pump and pump up the pressure above the operating pressure by immersing the assembled structure in water or generously lubricating the seams with soapy water. The appearance of bubbles will indicate places that require additional sealing.
Assembling the electrical circuit and connecting the relay
The electrical part requires precision, since operational safety depends on it. The standard connection diagram includes a pressure switch that breaks the power circuit when the upper pressure limit is reached and closes it when it drops to the lower threshold.
To connect, you will need to disassemble the pressure switch housing and study the location of the contacts. They are usually marked or have a schematic image on the inside of the lid. The phase wire from the network is connected to the relay input, and from the output goes to the compressor motor.
Connection diagram:Network (220V) -> Pressure switch -> Compressor motor
-> Grounding -> Housing
Important correct configure Pressure differential on the relay. For airbrushing, the lower threshold is usually set at about 4-5 atmospheres, and the upper threshold at 6-7 atmospheres. This will ensure a stable air flow without sudden jumps that could spoil the result of the work.
☑️ Electrical check
Do not forget to install a fuse or circuit breaker in the power supply circuit. This will protect the wiring from overload in the event of a motor jam or short circuit. The cross-section of the wires must correspond to the engine power, usually 1.5 mm² copper is sufficient.
Organization of an air purification system
One of the main problems of homemade compressors is the presence of oil and moisture in the exhaust air. Refrigeration compressors are often oil-based, and microscopic drops of oil along with condensation can get into the airbrush, ruining the design.
To solve this problem, an air preparation unit is installed between the receiver and the airbrush. It consists of filters connected in series: first there is a coarse filter (oil-dryer separator), then a fine filter with a carbon element.
| Filter type | Function | Replacement frequency |
|---|---|---|
| Cyclone separator | Catches the bulk of water and oil | As it accumulates |
| Carbon filter | Removes oil mist and odors | Every 50 hours |
| Micron filter | Retains solid particles | When pressure drops |
Install silica gel desiccant into a transparent filter cup to visually control moisture saturation. When the granules change color, they must be replaced or regenerated by heating. This simple solution will ensure your job doesn't get any unwanted craters.
⚠️ Attention: Don't ignore installing filters, even if you're only using the compressor to inflate your tires. For airbrushing, air purity is a critical quality parameter.
Reducing noise and vibration levels
Although refrigeration compressors are considered quiet, their humming can be annoying in a confined workshop space. In addition, the vibration is transmitted to the table and resonates, creating additional noise. An effective solution is to make a noise-absorbing box.
The box is made of plywood or chipboard, the inner surface of which is covered sound-absorbing material, for example, with polyurethane foam or mineral wool. It is important to provide holes for ventilation, otherwise the motor will overheat and fail.
To attach the compressor to the base, use rubber gaskets or special vibration mounts. This will prevent vibration from being transmitted to the floor and table. Also check the tightness of all bolted connections, as over time they can become loose from vibration.
Place the compressor station at some distance from the workplace, connecting them with a long hose. This will not only reduce the noise level, but also reduce the amount of condensate entering the tool, since the air will have time to cool in the hose.
First launch and system setup
After assembling all the components, the moment of truth comes - the first launch. Turn on the compressor and carefully monitor the pressure gauge readings. The engine should run smoothly, without jerking or extraneous knocking, gradually gaining pressure.
Check the operation of the pressure switch: when the pressure gauge needle reaches the upper value, the engine should automatically turn off. When you open the tap and bleed air to the lower threshold, the engine must start again. If this does not happen, it is necessary to adjust the screws on the relay.
Be sure to check the temperature of the compressor housing after 10-15 minutes of operation. If it heats up to the point where it is impossible to hold your hand, it means that the thermal regime is disturbed or there is insufficient lubrication. In this case, take a break and check the ventilation system.
Carry out regular maintenance: drain the condensate from the receiver, check the oil level (if the compressor is oil-based) and change the filter elements. A careful attitude will extend the life of your homemade product for many years.
Is it possible to use a compressor without a receiver?
Theoretically it is possible, but for airbrushing this is categorically not recommended. Without a receiver, the air flow will pulsate in time with the piston, which will lead to stains and uneven paint application. In addition, the motor will work constantly, which will quickly lead to its overheating.
What kind of oil should I fill into the compressor from the refrigerator?
Most modern compressors are filled with synthetic polyester oil (POE) and are sealed. If the oil level drops, you need to add strictly compatible synthetic oil. Mineral oil can react with synthetic residues and form an acid that destroys the windings.
Why does the compressor hum but not pump?
Most often this indicates a breakdown of the valve group or piston system inside the sealed housing. A broken connecting rod could also be a possible cause. In a home workshop, repairing such components is impossible; replacement of the unit is required.