How to remake a refrigerator compressor: step-by-step diagrams and expert advice

An old refrigerator that has served its purpose is often sent to a landfill entirely - but in vain. His heart compressorcan find a second life in a workshop, garage or even a household. With minimal costs (or without them at all), it turns out to be a full-fledged air pump, spray gun, and with modification - even sandblasting machine or airbrush. The main thing is to understand the principles of operation and follow safety precautions.

In this article Let's look 5 proven methods for alteringfrom the simplest pump for inflating wheels to semi-professional equipment for painting. You will learn which compressor models (Danfoss, Embraco, Secop) are better suited for remodeling, how to calculate productivity, avoid overheating and even automate work using a pressure switch. And also - why you can’t use a compressor from a refrigerator with a No Frost system without modifying the oil circuit.

1. How does a refrigerator compressor work and what can be made from it

A refrigerator compressor is one that pumps refrigerant (freon) through the system. Its key features: sealed piston pump, which pumps refrigerant (freon) through the system. Its key features:

• 🔹 Low input pressure (usually 0.5–1 atm) and high output (up to 15–20 atm depending on the model).
• 🔹 Oil system: the compressor is lubricated with a special oil, which circulates together with freon.
• 🔹 Electric motor with a starting relay, designed for long-term operation (but with interruptions!).

Suitable for conversion linear (piston) and rotational compressors. But inverter (for example, in models Samsung Digital Inverter or LG Linear Compressor) they require complex modification of electronics - without experience it is better to avoid them.

From a refrigerator compressor you can actually assemble:

• 🚲 Pump for inflating wheels (bicycle, car, boat).
• 🎨 Spray gun for painting small parts or furniture.
• 🏗️ Sandblasting machine (you will need a sandblasting gun and a container for abrasive).
• 🔧 Pneumatic tools: wrench, screwdriver, pumping gun brakes.
• 💨 Aquarium aerator or pond (at very low pressure).

⚠️ Attention: Compressors from refrigerators with a system No Frost often have two-stage lubrication system. Without modification of the oil filter, they can quickly fail when operating in air.

2. Tools and materials: what you will need for the conversion

Minimum set for a basic conversion (for example, into a tire pump):

For advanced projects (spray gun, sandblasting) you will additionally need:

• 🔧 Receiver (fire extinguisher cylinder, gas cylinder).
• 🛠️ Pressure reducer with pressure gauge.
• 🎨 Spray gun (for a spray gun).
• 🏜️ Sandblasting gun and abrasive (sand, soda).

Important: to work with higher pressure 3 atm be sure to use receiver (a container for smoothing pulsations). Without it, the compressor will overheat and the hoses may burst.

3. Step-by-step instructions: how to make a tire inflator

This is the simplest project that even beginners can do. You will need a compressor, a pressure gauge, a hose with a nipple and minimal soldering skills.

Step 1. Dismantling the compressor

• 🔌 Disconnect the refrigerator from the network, drain the freon (if it is still there).
• 🔧 Bite off or unsolder the copper ones tubes going to the compressor.
• 🔩 Carefully remove the start relay (it is attached to the compressor housing).

Step 2. Preparing for work in air

The refrigerator compressor is designed for freon, not air. To prevent it from burning:

• 🛢️ Change the oil: old oil is not suitable for freon. Use compressor oil (for example, Shell Coreana S4 P 100).
• 🔄 Rinse the system: fill in kerosene, rotate the shaft manually, drain.
• 🔧 Install the filter at the inlet (you can use a fuel filter from the car).

Step 3. Connecting hoses and pressure gauge

Connect to the outlet pipe of the compressor (usually it is thinner than the inlet):

1. Flexible hose with check valve (so that air does not return).
2. Pressure gauge (for pressure control).
3. Adapter for nipple (for connection to the tire).

Step 4. First start

Connect the compressor to the network via the start relay. Inflate the tire to the required pressure (usually 2-2.5 atm). for a passenger car). If the compressor turns off by itself, check the relay or install an additional thermal relay thermal relay.

⚠️ Attention: Do not inflate tires higher 3 atm without a receiver! data-i="171">3 atm

4. Conversion into a spray gun: diagrams and nuances

To paint parts you need a stable flow of air with pressure 2–4. atm. The refrigerator compressor will cope, but it will require modification:

What to add to the basic scheme:

• 🎯 Receiver (cylinder 10–50 l) to smooth out pulsations.
• 📉 Pressure reducer with a pressure gauge (for precise adjustment).
• 🔫 Spray gun (for example, SATA RP or Wagner W 550).
• 💧 Moisture separator (required - otherwise the paint will “spit”).

Connection diagram:

Compressor → Check valve → Receiver → Moisture separator → Gearbox → Spray gun

Key settings:

• 🔧 Pressure at the inlet to the gun: 2–2.5 atm (for most paints).
• 🎨 Distance to the surface: 15–20 cm.
• 💨 Gun movement speed: 30–40 cm/s (to avoid drips).

How to avoid air pulsations?

Pulsations occur due to piston design of the compressor. To reduce them, use a large-volume receiver (from 20 l) and install it as close as possible to the compressor. It will also help an additional filter muffler at the outlet of the receiver.

Important: for working with acrylic paints the pressure should be stable. If the compressor "sneezes" (sharply changes pressure), add a a second receiver or a pneumatic accumulator.

5. Sandblasting machine from a refrigerator compressor

Sandblasting is a more complex project, as it requires high air flow (from 150 l/min). withEmbraco EGX 90 or Danfoss NL6) will only cope with small-sized work (cleaning rust on bolts, small parts).

What you will need:

• 🏜️ Sandblasting gun (for example, Kraftmann 57611).
• 🧂 Abrasive: sand (0.2–0.5 mm fraction), soda, glass beads.
• 🛢️ Container for abrasive (you can use a modified plastic bottle).
• 🔄 Check valve at the inlet of the gun (so that sand does not clog the hoses).

Assembly diagram:

Compressor → Receiver (50 l) → Moisture separator → Gun → Sand container data-i="229">4–6 atm

Nuances of work:

• 🔧 System pressure: 4–6 atm (lower - weak effect, higher - risk of hose rupture).
• 🕳️ Distance to surface: 5–10 cm.
• 😷 Be sure to use respirator i glasses!

⚠️ Attention: Do not use river. sand - it contains moisture and can clog the gun. It is better to take dry quartz sand or crushed glass.

6. Automation: pressure switch and overheating protection

Manual control of the compressor is inconvenient and dangerous. data-i="244">(for example,

• 🔄 Pressure switch (For example, RDM-5 or Condor MDR 2).
• 🌡️ Thermal relay (for shutdown in case of overheating).
• 🔌 Start relay (if the original one burned out).

How to connect the pressure relay:

1. Connect the relay to output pipe the compressor.
2. Set lower limit (on) to 2 atm, upper (off) to 4 atm.
3. Connect the relay to the compressor power supply circuit.

To protect against overheating:

• Install thermal relay on the compressor housing (for example, KSD301 at 60°C).
• Add cooler from the computer for additional airflow.

Checking operation:

1. Turn on the compressor - it should pump the receiver to 4 atm and turn off.
2. Bleed the air to 2 atm - the compressor will turn on again.
3. If the automation does not works - check the relay settings or the connection circuit.

7. Frequent errors and how to avoid them

Even experienced technicians sometimes make mistakes that lead to compressor failure or injury. Here are the most common:

A few more critical points:

• 🔌 Incorrect connection of the relay: if you mix up the contacts, the compressor will work without stopping.
• 💥 Use of uncertified cylinders as a receiver - risk of explosion!
• 🔧 Lack of check valve - when the air is turned off will return to the compressor, creating resistance.

If the compressor starts knocking or heat more than usual, immediately turn it off and check:

• Oil level.
• Filter cleanliness.
• Belt tension (if any).

8. data-i="308">In addition to pumps and a spray gun, the following is collected from the refrigerator compressor:

In addition to pumps and a spray gun, the following is collected from the refrigerator compressor:

Airbrush for artistic painting

• 🎨 Suitable for modeling, nail art, painting on fabric.
• 🔧 Required gearbox with fine adjustment (0.5–1.5 atm).
• 💡 Use double action airbrushes (for example, Iwata Revolution CR).

Pneumatic impact wrench

• 🔩 Enough power for nuts up to M12.
• 🔧 You need receiver 20–30 l i pneumatic impact wrench (for example, Jonnesway AIR2112).

Aeration system for aquarium

• 🐟 The pressure should be not higher than 0.5 atm.
• 💨 Use a sprayer for an aquarium i flow regulator.

Vacuum pump

• 🧪 Suitable for laboratory work or vacuum packaging.
• 🔄 It is necessary turn the valves (make the input the output and vice versa).

FAQ: Answers to frequently asked questions

❓ Is it possible to use a compressor from a No Frost refrigerator?

Yes, but it is necessary replace the oil for synthetic (for example, POE oil) and install additional filter to separate the oil from the air. No Frost compressors often have a higher operating pressure, which can be a plus for sandblasting.

❓ How long will a converted compressor last?

If used correctly (regular oil changes, filters, cooling breaks) - 3–5 yearsIf you use it as a temporary pump (for example, to inflate wheels) -. up to 10 years.

❓ What kind of oil should I fill in?

Suitable for air compressor oil viscosity ISO VG 100 (for example Shell Coreana S4 P 100 or Mobil Rarus 429). For compressors No Frost — POE oil (polyester).

❓ Is it possible to connect the compressor directly to the spray gun without a receiver?

Technically yes, but painting quality will be low due to air pulsations. Without a receiver, the paint will lie unevenly, and “spitting” is possible. The minimum volume of the receiver for a spray gun is 10 liters.

❓ How to calculate the compressor performance?

The capacity is indicated on the compressor nameplate cub.m/hour or l/min. For reference:

• Embraco EGX 70: ~100 l/min.
• Danfoss NL8: ~150 l/min.
• Secop (formerly Danfoss) SC15M: ~200 l/min.

For sandblasting you need from 150 l/min, for a spray gun it is enough 50–100 l/min.