Solder a copper pipe


The soft soldering of copper pipes is a common joining method for various areas in building services. A guide and what to consider when soldering a copper pipe, we have summarized below for you.

Typical applications of copper pipes

Copper pipes have a variety of advantages, which is why they can be used for a wide variety of applications. Alone in the building services this would be the use as:

  • drinking water pipes
  • Heating cables
  • for other water pipes (rain and sewage)
  • in solar technology
  • Gas pipes (liquid and natural gas)
  • Refrigerant piping (oil and refrigerant gas in air conditioning systems, refrigeration systems)

In addition, there is the use as a hydraulic (oil) or pneumatic (air) line.

Joining techniques for copper pipes

There are several techniques for joining:

  • the gluing
  • brazing (soft and brazing, high temperature brazing HTL)
  • the welding
  • the pressing
  • the pressing and soldering in combination

Restrictions when soldering copper pipes

But not every technology can be used for every application. Soft soldering is used primarily for drinking water pipes and heating systems, provided that the temperature of the water is limited to 110 degrees Celsius.

In particular, in the soft soldering of drinking water pipes, the even stricter regulations, among others, the DVGW (German Association of Gas and Water Department) are observed (DVGW worksheet GW 2). In addition, the fittings must be equipped with the following markings:

  • RAL quality mark
  • Manufacturer's mark
  • DVGW approval mark (on the packaging of the fittings)
  • Connection diameter

Information about solder and flux

For soldering solder paste or flux and solder (full solder without flux especially when soldering drinking water pipes) are needed, not forgetting the tools and tools for preparing the copper pipes before soldering. More about this in the following manual for soldering copper pipes.

Step by step instructions for soldering copper pipes

  • Fittings (connectors)
  • copper pipes
  • Soft solder (pay attention to the release in drinking water pipes!)
  • Flux or solder paste (watch out for the release of drinking water pipes!)
  • Pipe cutter or fine hacksaw
  • Deburring
  • Calibration mandrel and cylinder
  • abrasive fleece
  • Copper or brass wire brush (inner tube side)
  • a damp cloth
  • suitable blowtorch

1. Prepare the copper pipes

First you have to cut each copper tube to size. Then the copper pipe is deburred. Finally you have to calibrate the copper tube (inside and outside).

2. Why Entraten is so important

Should one of the copper pipes not be properly deburred, this can lead to turbulence by the subsequent transport medium and consequent erosion corrosion. For more information, see "Copper pipe corrosion" and "Copper pipe pitting".

3. Why calibration is so important

The calibration is so important because too much pressure during cutting a copper pipe can be easily deformed. When soldering a copper pipe, however, the capillary effect is used, which is why the fittings are often referred to as capillary fittings. If the gap is exactly between 0.1 and 0.2 mm, it pulls the molten solder circumferentially into the gap.

4. Clean copper pipe and fitting (inside) bare

With the fleece, the copper tube is now ground to the insertion length with the fleece metallic blank. The fittings are polished and cleaned accordingly.

5. Apply the flux

Now the solder paste is applied. This is applied only on the outside of the copper pipe, not inside the fitting. Pay attention to an even application.

6. Solder the copper pipe to the fitting

Insert the copper pipe into the fitting and wipe off excess flux with the cloth. With a suitable flame (blue, size adapted to the copper tube thickness) you now heat the soldering area to about 250 degrees Celsius. However, when soldering, you will not see a color change like when brazing a copper pipe (cherry red glow).

However, the solder paste will start to melt in the correct temperature range and will get a silvery color. Now hold the flame away from the solder joint and pull the solder, which melts simultaneously at the solder joint, in a semicircle movement along the joint of the fitting and the copper pipe. Due to the capillary effect, it draws the solder circumferentially into the seam and fills it.

7. Required amount of soft solder

There is a simple rule of thumb for the amount of solder required: place the solder over the pipe cross-section and let it stand out easily. On the opposite side, bend the plumb bob. The front kinked solder area corresponds to the required amount.

8. After soldering the copper tube

After soldering, wipe off excess flux with the damp cloth. Keep in mind that during installation as domestic technology, subsequent pressure and tightness tests are required according to the use.

Tips & Tricks

If possible, soldering should be preferred to brazing copper pipes. Brazing can cause tinder inside the pipe. If this is not completely removed, it can lead to pitting, even if the rest of the lines is properly protected by the passive layer.
Solder a copper pipe

FAQ - 💬

❓ Do you need flux to solder copper pipe?

👉 Copper piping is joined together using flux and soldering. In the soldering process, heat is applied to the joint where the pipe and fitting meet. The gap between the joint is filled with molten metal. This guide identifies the types of solder available as well as the right flux for soldering your project.

❓ How do you solder a good copper pipe connection?

👉 3:455:05How to Solder Copper Pipe The CORRECT Way | GOT2LEARNYouTubeStart of suggested clipEnd of suggested clipSo keep on heating it up while testing your solder. Every now and then to see if it gets sucked inMoreSo keep on heating it up while testing your solder. Every now and then to see if it gets sucked in eventually. Your joint will be hot enough to accept your solder.

❓ Can a DIY solder copper pipe?

👉 With a little practice, anyone can solder copper water pipe. Learn how to cut, clean and flux pipe and fittings, how much solder to use, and how to check for a leak. We'll show you how to solder like a pro so you can tackle your next DIY plumbing job.

❓ Where do you put flux when soldering copper pipe?

👉 0:302:53Fluxing & Soldering TechniquesStart of suggested clipEnd of suggested clipIt also protects the clean surface from reoxidation during heating and it promotes wetting of theMoreIt also protects the clean surface from reoxidation during heating and it promotes wetting of the surfaces by the solder alloy stir the flux to activate it then use a brush to apply a thin coating to

❓ Can solder fix a cracked copper pipe?

👉 Depending on your skills and resources, you can repair cracked copper pipes through soldering, plugging with epoxy or wrapping with a commercial wrap seal kit. All three techniques make a watertight, permanent repair.

❓ Can you solder copper pipe leak?

👉 Clean the damaged area with an abrasives pad and then add the flux which you will use for soldering to the pipe. Heat the flux with a blowtorch until it changes colour and then add solder into the hole. This will block up the hole, sealing the leak and returning the pipe to full working order.

❓ Is soldering pipes going to be illegal?

👉 State law prohibits the use of any pipe, pipe or plumbing fitting or fixture, solder, or flux that is not lead free in any public water system or facility providing water for human consumption.

❓ Can you use Vaseline instead of flux for soldering?

👉 Many people have found that petroleum jelly works just as well as commercial flux. Combine that with the fact that it's usually much cheaper, melts quickly from the heat of the soldering iron, and can be used safely for many types of soldering jobs, petroleum jelly the one flux alternative you will want to check out.

❓ What are the 3 steps to soldering a copper pipe?

👉 How to Solder Copper Pipe

  1. Step 1: Cut Your Pipe. The first step to assembling copper pipe is to cut your pipe to length. ...
  2. Step 2: Cleaning the Pipe and Fitting. ...
  3. Step 3: Flux It. ...
  4. Step 4: Heat It. ...
  5. Step 5: Solder It. ...
  6. Step 6: Re-soldering a Joint. ...
  7. Step 7: Supporting Joints. ...
  8. Step 8: You're Done.

❓ Is soldering copper pipe difficult?

👉 Soldering copper water supply lines is not a difficult skill. Even a rookie can learn to solder leak-proof joints in 30 minutes. The process is simple—if you follow a few basic guidelines. In this story we'll show you how to solder copper quickly and easily.

❓ wHy is soldering pipe illegal?

👉 In 1986 Congress Amended the Safe Drinking Water Act, prohibiting the use of pipes, solder or flux that were not “lead free” in public water systems or plumbing in facilities providing water for human consumption.

❓ How does soldering work on copper pipe?

👉 Soldering is a process of joining different types of metals together. The solder itself is a metal alloy. It is typically made of tin or led, which is melted using a hot iron or torch. It is best to avoid lead solders, as they are toxic. This heat creates an electrical bond with the copper pipe.

❓ How do I solder a copper faucet?

👉 Apply the right amount of solder, e.g., half-inch of solder for half-inch copper pipe. Excess solder restricts water flow and sometimes forms small balls that break loose and damage the faucet valves Wipe off any solder clogging the threads.

❓ How do you solder copper pipe with a torch?

👉 Soldering copper pipes demands relatively large amounts of high-intensity heat, usually 400-500 degrees Fahrenheit. A propane torch fitted with the correct size tip comes in handy. Be sure to apply heat uniformly around the fitting for 8-10 seconds. Note that the amount of heat required varies depending on the project.

❓ What is solderless copper bonding for pipe fittings?

👉 This is a process called solderless copper bonding, and it uses a liquid durable polymer that’s applied to rigid pipe fittings in order to literally weld them together hermetically. It’s a complex process and worth hiring a professional to complete. How to solder copper pipe in tight places?


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