We solder the copper tubes of the refrigerator: a complete guide from preparation to checking the tightness

Soldering copper pipes in a refrigerator is a task that frightens many novice craftsmen. However, with the right tools and understanding of the process, even a novice can handle repairs without the need for specialists. The main thing is to follow safety precautions and not skip key steps: from cleaning the surface to checking the tightness of the connection. In this article we will analyze the entire process from A to Z, including the selection of materials, preparation of tubes and the nuances of working with refrigerant.

Many people mistakenly believe that an ordinary soldering iron for electronics is sufficient for soldering refrigeration tubes. In fact, this requires gas burner with a flame temperature of at least 800°C, special copper flux and high-temperature solder. In addition, working with freon requires special care - its leakage not only negates all efforts, but is also dangerous to health. If you have never encountered the repair of refrigeration equipment, start with theoretical preparation and be sure to read the section about common mistakes.

Is it worth taking on soldering yourself? It all depends on the scale of the damage. It is quite possible to solder a small crack or broken pipe at home. But if we are talking about replacing the compressor or completely refilling the system with freon, it is better to turn to professionals. In any case, knowledge of the basics of soldering copper pipes will be useful to every owner of a refrigerator over 10 years old - sooner or later, even the most reliable equipment requires repair.

1. Preparation of tools and materials

Before starting work, make sure that you have everything you need. The reliability of the connection directly depends on the quality of the tools. Here is a basic set that you cannot do without:

• 🔥 Gas burner with an adjustable flame (propane-butane or acetylene). The power of a household burner for soldering copper tubes with a diameter of up to 10 mm is quite sufficient.
• 🧪 Flux for soldering copper (for example, F-SW21 or Castolin 190). It removes the oxide film and improves the adhesion of the solder to the metal.
• 🔗 Solder —it is better to choose copper-phosphorus (for example, CuP6) or silver (for example, Ag5) for high temperature soldering.
• 🧽 Metal brush or sandpaper (120–240 grit) for cleaning tubes.
• 🩹 A rag made of non-flammable material (asbestos or fiberglass) to protect adjacent parts from overheating.
• 🛠️ Pipe cutter or hacksaw for metal —if cutting of the tube is required.
• 🧊 Nitrogen cylinder (optional)—for purging the system before soldering, if the refrigerator is already filled freon.

Also prepare personal protective equipment: gloves made of heat-resistant material, safety glasses and a respirator. Flux and solder fumes are toxic, and open torch flames can cause burns. Work in a well-ventilated area or outdoors.

Important: If you solder tubes in a running refrigerator, first pump out the freon using a vacuum pump. Soldering under refrigerant pressure is strictly prohibited - this can lead to an explosion!

2. Selecting solder and flux: which is better for the refrigerator?

The strength of the connection and the durability of the repair depend on the correct choice of solder and flux. Not all materials are suitable for soldering copper refrigerator tubes. Here are the key criteria:

• 🔥 Solder melting point must be above the operating temperature of the refrigeration system (usually 60–120°C). The optimal range is 600–900°C.
• 🧪 The composition of the solder —avoid lead alloys (they are toxic). It is better to use copper-phosphorus (CuP6) or silver (Ag5, Ag15) solders.
• 💧 Flux should be active, but not aggressive. Borax-based fluxes (F-SW21) or special pastes for copper (Castolin 190).

The table below shows a comparison of popular solders for soldering copper tubes:

If you are soldering pipes in a system with freon, avoid solders with a high zinc content - they can react with the refrigerant. Also, do not use acid fluxes (for example, based on hydrochloric acid), as their residues will lead to corrosion.

3. Preparing tubes for soldering: cleaning and processing

The quality of soldering depends 80% on surface preparation. Even minor contamination or an oxide film can lead to a weak connection. Follow this. algorithm:

1. Cleaning the tubes. Remove any remaining solder, paint or oil using a metal brush or sandpaper. Clean until shiny - the copper should turn light pink.
2. DegreasingWipe the tubes with acetone or a special degreaser. will remove grease marks that interfere with adhesion.
3. Applying flux.. Using a brush or applicator, evenly cover the soldering area with a thin layer of flux. Avoid excess - it may flow inside the tube.
4. Assembling the connection. Insert the tubes into each other (if it is a joint) or overlap tightly (at least 5 mm). Secure them with a clamp or vice to avoid displacement during heating.

If the tube is damaged (crack, rupture), cut it with a pipe cutter or with a hacksaw, removing the defective area. The edges should be smooth, without burrs. For cutting, use only a specialized tool - a grinder or metal scissors can deform the edge.

Attention: If you are working with a tube connected to a compressor, be sure to pinch it before cutting to avoid chips getting inside the system. Metal dust can damage the valves. filters.

Clean the surface to a shine|Degrease with acetone|Apply a thin layer of flux|Secure the connection with a clamp|Blow the system with nitrogen (if required)-->

4. instructions

Now we move on to the most important stage - soldering. Here it is important to control the temperature, uniformity of heating and amount of solder. Follow the instructions: Turn on the burner and adjust the flame to medium power (blue flame core 2-3 cm high). Heat the soldering area evenly, moving the flame in a circle. massive part.

1. Heating of the connection. Turn on the burner and adjust the flame to medium power (blue flame core 2-3 cm high). Heat the soldering area evenly, moving the flame in a circle. Start with a larger piece.
2. Temperature control. The copper must be heated to the melting temperature of the solder (for CuP6 this is ~700°C). You can check readiness by touching the solder to the soldering area - if it starts to melt, you can proceed.
3. Applying solder. Apply the solder rod to the joint (not to the flame!). It should melt from the heat of the tube, not the burner. Distribute the molten solder evenly over the entire seam.
4. Cooling. After soldering is completed, allow the joint to cool naturally. Do not cool with water or air - this can cause microcracks.

The optimal heating time depends on the diameter of the tube:

• ⚡ Tubes with a diameter of up to 6 mm - 10–15 seconds.
• ⚡ Tubes 6-10 mm - 20-30 seconds.
• ⚡ Tubes over 10 mm - 30-60 seconds (preheating is recommended).

Critical moment: If the solder does not fill the seam, but rolls off in droplets, this means that the surface is not sufficiently cleaned or is overheated. Stop soldering, let the tube cool, strip it again and apply a new layer of flux.

What to do if the solder does not stick?

If the solder does not wet the copper, check:

1) Quality of stripping - the oxide film may remain in microcracks.

2) Heating temperature - copper must be evenly heated (visually this can be seen by the change in the color of the flux).

3) Compatibility of flux and solder - some combinations do not work together.

4) Solder quality - cheap alloys often contain impurities that impair soldering.

5. Checking the tightness and testing the system

After soldering, you need to make sure that the connection is tight. Even a small microcrack will eventually lead to a freon leak. Here's how to check the quality of work:

• 🔍 Visual inspection. The seam should be smooth, without pores or sagging. The color is uniform, without dark spots (a sign of oxidation).
• 💨 Check with soap solution. Apply a foaming solution (soap + water) to the seam and supply nitrogen to the system under a pressure of 10–15 atm. If bubbles appear, there is a leak.
• 📉 Evacuation. Connect a vacuum pump and evacuate the system to a pressure of -0.1 atm. If the pressure does not hold, look for the leak.
• 🧊 Refilling with freon. After successful tests, charge the system with refrigerant (the type of freon is indicated on the refrigerator nameplate). Use scales for accurate dosing.

If you find a leak, do not try to cover it with sealant or cold welding. The only reliable way is to resolder the connection. A common mistake made by beginners is to ignore minor seam defects, which after 1–2 months lead to repeated depressurization.

Attention: After charging with freon, turn on the refrigerator and check its operation within 24 hours. If the compressor runs without stopping or does not cool, there may be undercharging or blockage in the system.

6. Common mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes when soldering copper pipes. Here are the most common of them and ways to prevent them:

• 🔥 Overheating tubes —leads to annealing of copper (it becomes brittle) and burnout of the flux. Solution: Control the color of the flame (there should be a blue core) and do not hold the burner in one place for more than 5 seconds.
• 💧 Excess flux —its residues cause corrosion. Solution: Apply flux in a thin layer and remove excess after soldering with a damp cloth.
• 🔗 Insufficient overlap of tubes —the seam is weak. Solution: Minimum overlap is 5 mm for tubes up to 10 mm and 10 mm for larger tubes.
• 🧊 Soldering under freon pressure —risk of explosion! Solution: Always bleed off the refrigerant before soldering.
• 🛠️ Using the wrong solder —for example, tin-lead for high-temperature systems. Solution: Check the solder markings for compliance with the temperature conditions.

Another typical problem is clogging the system with chips or oxides. To avoid this:

1. Always purge the tubes with nitrogen before soldering.
2. Use a filter drier (replace it after repair).
3. Do not clean the tubes with an angle grinder - only with a brush or sandpaper.

⚠️ Attention: If after soldering the refrigerator begins to make more noise or the compressor turns off a few seconds after starting, dirt or moisture has probably entered the system. In this case, a complete flushing of the circuit will be required.

7. Advice from professionals: how to make soldering more reliable

Experienced refrigeration workers share life hacks that help achieve an ideal seam:

• 🔥 Use a "reflective" screen" from asbestos cardboard to protect adjacent parts (for example, plastic fasteners) from overheating.
• 🧲 Magnetic solder holder will simplify work in hard-to-reach places. It can be made from a neodymium magnet and wire.
• 💡 Backlight —use an LED flashlight on your forehead to better see the soldering area in the depths of the refrigerator.
• 📏 Template for overlap —cut make a strip of tin 5 mm wide and use it as a limiter for uniform overlap.

If you solder tubes in a refrigerator with a system No Frost, be especially careful with heating the evaporator. Its aluminum fins may become deformed at temperatures above 150°C. In this case, use a heat-dissipating screen or cool adjacent areas with a damp cloth.

Preventive advice: After repair, install on the tubes heat shrink sleeve or wrap the seam with fiberglass tape. This will protect the connection from vibration and mechanical damage.

FAQ: Frequently asked questions about soldering copper tubes

Is it possible to solder copper tubes of a refrigerator with regular soldering iron?

No, a regular soldering iron is not suitable for electronics. The temperature of its tip (maximum 400–450°C) is not sufficient for high-temperature soldering of copper tubes. This task requires a gas burner with a flame temperature of 800°C.

What freon is used in my refrigerator and can it be replaced?

The type of freon is indicated on the nameplate (usually on the back wall of the refrigerator). Modern models run R134a or R600a. It is impossible to replace the refrigerant with another without reworking the system - this will lead to breakdown of the compressor. Exception: transition from R12 to R134a (an oil change in the compressor is required).

How much does it cost to repair refrigerator tubes in a service center?

The cost depends on the complexity of the work:

• Soldering one tube - from 1500 to 3000 rubles.
• Replacement of a section of a tube with refilling freon - 3500-6000 rubles.
• Full re-soldering of the circuit (in case of serious damage) - 8000-15000 rubles.

Independent repair will cost 500–1500 rubles (the price of the torch, solder and flux).

What to do if the refrigerator does not cool after soldering?

There may be several reasons:

1. Insufficient freon charging - check the pressure in the system with a pressure gauge.
2. Clogged in the capillary tube - flushing or replacement is required.
3. Compressor malfunction - check its winding resistance.
4. Freon leakage through a poor-quality seam - apply a soap solution to all connections.

If you are not sure of the reason, contact a technician with diagnostic equipment.

Is it possible to solder aluminum refrigerator tubes in the same way as copper ones?

No, aluminum requires a special approach:

• Use solder based on zinc or aluminum (for example, Al-Si).
• The flux should be intended for aluminum (for example, F-AL1).
• Soldering temperature is 550–600°C (aluminum melts at 660°C).

Soldering aluminum is more difficult than copper and often requires argon welding. Aluminum tubes are rarely found in refrigerators (usually in evaporators. No Frost).