Disassembling an old refrigeration compressor is not just a way to obtain valuable non-ferrous metal, but also a process that requires strict adherence to safety precautions. Sealed casing devices often hide residual refrigerant under high pressure, which makes careless work with the angle grinder potentially dangerous. Many craftsmen, trying to quickly remove copper, neglect the preparatory steps, which can lead to injury or damage to the cutting tool.
Before proceeding with mechanical destruction steel casing, it is necessary to understand the design of the unit. Inside there are two main parts: the electric motor and the compressor mechanics, immersed in oil. Inside the compressor there may be a residual freon pressure of up to 5-8 atmospheres even after 10 years downtimetherefore, the first stage of work should always be aimed at decompressing the system.
This article describes in detail the algorithm of actions that allows you to safely separate the housing and remove the windings for subsequent scrapping. We'll look at the tools needed, methods to prevent flying sparks, and how to effectively separate steel core plates. Your task is to turn hazardous waste into a clean, sorted resource.
Necessary tools and protective equipment
To do the job well, you will need reliable power tools that can handle thick-walled steel. The main tool will be an angle grinder, popularly called a “grinder”. The diameter of the cutting disc must be matched to the power of the tool, but the optimal solution for deep cuts is 125 mm or 150 mm. The use of dull discs is unacceptable, as this increases the risk of their destruction at high speeds.
The personal safety of the operator comes first, because the process is accompanied by the formation of small metal chips and sparks. Be sure to wear safety glasses with side protection and thick gloves made of split leather or Kevlar. Clothing should fit tightly to the body to prevent rotating parts of the tool from getting into the fabric.
- 🛡️ Angle grinder with a supply of cutting discs for metal 1.0–1.2 mm thick.
- 🧤 Thick work gloves and safety glasses (preferably with anti-fog coating).
- 🔧 A set of wrenches and pliers for dismantling the pipes.
- 🔨 A hammer and chisel for the final separation of parts after cutting.
Do not forget that electric current metal dust forms a dangerous mixture. You should work in a well-ventilated area or outdoors, but under a canopy to prevent moisture from entering the power tool. Prepare a container in advance to collect draining oil, which can be toxic.
⚠️ Attention: It is strictly forbidden to use a hacksaw or a hand jigsaw to cut the compressor housing. This is not only extremely time-consuming, but also dangerous: the tool can slip, and vibration during prolonged sawing will increase the risk of hand injury.
Preparing the compressor and releasing pressure
The first step in the recycling process is the complete preparation of the unit. The compressor must be disconnected from the refrigeration system, and all copper pipes must be cut off or sealed off. If the device is still sealed, there is guaranteed to be gas inside. Even if the pipes appear to be open, residual pressure may remain in the deep cavities of the housing residual pressure.
For safe opening, it is necessary to drill a hole in the upper part of the dome or in the area of the suction pipe. Use a metal drill with a diameter of 3–4 mm. At the moment of drilling, you will hear a characteristic hissing sound of escaping gas. Keep your face and hands away from the jet, as oil may fly out along with the freon.
After bleeding the main volume of gas, it is recommended to let the compressor “breathe” for a while 15–20 minutes. This will allow any remaining refrigerant, which may be heavier than air and accumulate in the lower part of the housing, to evaporate. Only after this can you proceed to the main cutting stage.
It is important to consider that older models of refrigerators could use refrigerants that, when in contact with an open flame or a high-temperature spark, can form toxic compounds. Therefore, working in a respirator will not be an unnecessary precaution.
Technology for safe cutting of the casing
The most critical stage is the direct cutting of the steel casing. The compressor housing consists of two hemispheres welded together at the equator. Your job is to cut this weld in a circle. For ease of operation, secure the compressor in a vice or rest it securely on a hard surface so that it does not roll while cutting.
Start cutting from the top, gradually lowering towards the equator. Move the grinder smoothly, without pressing hard, allowing the disc to do the work itself. Excessive force may cause the disc to jam or break. If the disk gets hot, let it cool at idle speed.
☑️ Procedure for cutting
When working with grinder it is important to maintain the cutting angle. The disk should enter the metal perpendicular to the surface. If you try to change the angle of the tool while the disk is deeply immersed, it may be pinched by the metal, which will cause the tool to jerk.
In some cases, the weld may be hidden under a layer of paint or rust. You can visually determine the joint line by the characteristic thickening or change in color of the metal. Draw a chalk line around the circumference to help you stay on track and make an even cut.
⚠️ Attention: Do not try to cut the housing across the motor poles. There are copper windings inside that you will damage, and there is also a risk of bumping into the motor shaft, which will ruin the cutting disc. Cut strictly along the equatorial seam.
Removing the electric motor and rotor
After the circular motion is completed, the top cover is removed. The internal structure opens before you: a stator with windings and a rotor mounted on the compressor shaft. Often the rotor is tightly seated on the shaft and requires physical effort or leverage to remove it.
To remove the rotor, flip the bottom of the housing over. The compressor shaft usually protrudes outwards. Clamp the shaft in a vice (using a soft pad to avoid damaging the threads or surface) and gently tap the housing to try to budge the rotor. If this does not help, you can use a puller, but in garage conditions they often make do with a mounting blade.
The stator is a stacked core with wound copper. It can be secured in the housing with three bolts or simply pressed in. If there are no bolts, you will have to carefully knock the core out of the body using a wooden or rubber mallet. It is better not to use a metal hammer so as not to deform the copper.
What to do if the rotor cannot be removed?
If the rotor is soured on the shaft and cannot be knocked down, you can try to warm up the inside of the rotor with a hair dryer. Thermal expansion will help loosen the tightness. Do not use an open flame to avoid damaging the copper insulation if you plan to reuse the motor.
When removing, be careful of the wires. They may be short, and a sudden movement will cause them to break at the very exit of the grooves. If your goal is to recycle copper, this is not critical, but if you are planning on reworking the engine, the integrity of the leads is crucial.
Disassembling the stator and sorting the metal
The resulting access to the stator opens the way to the main value - copper. However, you can’t just pull out the winding. The stator core is assembled from thin plates of electrical steel, which are tightly compressed and often filled with varnish or compound. To get to the copper, you need to disassemble this “pie.”
There are two main ways to extract copper: burning and mechanical cutting. Burning (burning insulation on a fire) is a barbaric method that damages metal and pollutes the atmosphere. A professional approach involves mechanical destruction of the bonds between the plates.
Use a chisel and hammer to split the stacked core on one side. Apply blows to the end of the plates, being careful not to damage the copper wire itself. Once you split the steel cage, the plates will easily fall apart, freeing the coils.
| Metal type | Appearance | Magnetic properties | Note |
|---|---|---|---|
| Copper (winding) | Redish-golden | Not magnetic | Main valuable resource |
| Electrical steel | Silver, gray | Strongly magnetic | Inlaid plates |
| Aluminum (rare) | Silver-white | Not magnetic | Found in cheap models |
| Varnish/Insulation | Dark brown | Not magnetic | Requires removal |
After disassembling the stator you will be left with copper coils coated with varnish. To increase the scrap price, the varnish must be removed. This can be done thermally (carefully firing with a torch) or chemically, but the easiest way is to hand over “burnt” copper if the collection point allows it, although the price for it will be lower.
Common mistakes and safety precautions
In pursuit of speed, beginners often make mistakes that negate the entire result or lead to damage to the instrument. One of the most common is trying to cut the body without checking for oil. Residual oil in contact with a hot disk creates acrid smoke and can ignite.
Another mistake is using unsuitable disks. Thin cutting wheels (1mm) are designed for cutting, but are fragile. Thick grinding discs (2.5 mm or more) cannot be used for deep cuts: they are thick, create a wide groove and quickly overheat, which can lead to their rupture.
- 🚫 Do not cut the body if it is not fixed - vibration is inevitable.
- 🚫 Do not ignore the burning smell - this can burn varnish or oil.
- 🚫 Do not try to bend steel plates with your hands - the edges are razor sharp.
Remember that there are engine mounting springs inside the compressor. When cutting, they can shoot out if they are not first wedged or controlled. Always inspect the insides before completely separating the housing halves.
Is it possible to use the compressor after cutting the housing?
No, the seal is broken irrevocably. It is impossible to restore factory welding at home. However, the electric motor inside can be used for home-made machines, and the compressor unit itself (piston group) can be used for inflating tires or airbrushing, if you assemble a new harness.
How much copper can be obtained from one compressor?
The weight of the copper output depends on the power of the unit. A standard household refrigerator compressor typically produces between 100 and 250 grams of pure copper. In powerful industrial models, the yield can reach 500–700 grams.
Is compressor oil dangerous for the skin?
Yes, technical oil, especially from old Soviet refrigerators, may contain refrigerant breakdown products and be toxic. Avoid direct contact with skin and be sure to wash your hands with soap after work.