Induction brazing has emerged as a leading method for joining copper in various HVAC, automotive, and electrical industries. It offers numerous benefits, including precision, speed, and repeatability, making it a preferred choice for many applications. However, it requires specialized equipment and knowledge to achieve optimal results.

In this article, we will guide you through the induction brazing process of copper, covering everything from surface preparation to filler material selection.
Read on to discover how to leverage induction brazing to create strong and reliable copper joints for your specific needs.

Induction Brazing Copper: The Complete Process

A brief knowledge of induction heating and brazing is required to understand copper brazing.

Induction heating is melting metal workpieces by passing high-frequency AC through them. While brazing is a simple metal joining process in which two metals are joined by infusing a filler metal between them.

Brazing has many types based on the heat source employed. However, when an induction heater is used as a heat source for brazing, that is known as induction brazing.

The process of copper brazing involves multiple steps, which are outlined below:

Step 1: Cleaning the Copper Piping

To prepare the pipes for brazing, they are thoroughly cleaned inside out with a wire or rubbed with sandpaper to eliminate all contaminants. This step is necessary for a clean and robust induction brazed joint.

Step 2: Preparation of an Overlap/Socket Joint

Next, an overlap joint is formed to braze the copper pipes. This is a critical step since the strength of the joint will ultimately depend upon the overlap depth of pipes. As per the American Welding Society (AWS), the depth should be at least three times the thickness of copper pipes being brazed. Normally, industries go with much higher values to be on the safe side.

Step 3: Clamping the Pipe Setup

Clamping of the setup is also necessary to keep the joint in place before brazing. The pipes are temporarily clamped inside an induction coil or outside of it.

Since the induction coil is the heat source in this brazing technique, the whole need setup needs to be surrounded by it.

If a portable induction heater is used, the induction coil is usually placed over the clamped pipes setup. However, in some cases, the whole setup is placed inside the heavy-duty induction machine.

Step 4: Application of Filler Metal

The induction heater is turned on, and a filler metal, usually a rod, is applied to the joint. Based on the power rating, the heater remains turned on for 5 to 10 seconds. The higher the power rating, the less time it takes to braze the copper pipes.

Step 5: Cooling

After the brazing process has been performed, the copper joint is allowed to cool for an hour before it is ready for use.

Filler Metals and Flux used in Induction Brazing of Copper

Since we discussed fillers in the previous section, it is important to mention the common ones used. For induction brazing copper, two series of filler metals are employed:

  • BCuP alloy series
  • BAg alloy series

BCuP series alloys are rich in phosphorus, which acts as a flux during induction brazing. From this series, BCuP-2 is quite common for plumbing and HVAC applications. While for general piping applications, BCuP-3,4 or 5 are used as they are cheaper. The BAg alloy fillers are used when joining copper with dissimilar metals.

One of the pertinent points to note here is that the strength of an induction brazed doesn’t depend on the filler metals used. Instead, it is a function of clearance and overlapping depth between the two joined pipes.

Equipment Used in Copper Induction Brazing

The induction brazing process, as mentioned earlier, is carried out through induction heaters. Multiple types of induction heating machinery are available on the market, from portable induction heaters to heavy-duty commercial machines.

FOCO Induction, being one of the leading solutions providers in the induction industry, has also developed three products for induction brazing of copper:

FOCO Portable Induction Brazing Machine
Handheld Induction Brazing Machine
Automatic induction brazing machine

Applications of Induction Brazed Copper Pipes

Induction brazing is an ideal choice for use in HVAC industries, particularly for brazing copper pipes of a heat exchanger. Similarly, it is quite helpful for use in water distribution systems where metallic piping is used. Another use case is the automobile industry, where copper tubing is standard.

In short, some key domains where induction brazing of copper is in use include:

  • Heat exchangers
  • Copper ducts and valves
  • Water distribution and heating systems
  • Underground fuel and gas systems
  • Drainage and vents

See our induction brazing projects.

What Other Methods can be used to Braze copper?

Induction brazing is not the only technique for copper joints. Two other common methods, torch brazing and soldering, are used to connect copper pipes.

Torch brazing is the conventional brazing process in which a flame torch is used to heat the filler metal and fill in the clearance between the pipe joint.

Soldering copper pipes is pretty much similar to torch brazing. However, the process takes place at a slightly lower temperature and, thus, has low joint strength compared to brazing. It is a cost-effective solution for joining copper pipes and can be used for small-scale repair applications.


Due to its precision, speed, and efficiency, induction brazing has become a popular method for joining copper in various industries.

To carry out this process, the choice of filler metals depends on the application. However, it doesn’t directly affect the joint strength, which depends on the socket joint’s depth.

Apart from induction brazing, one can also create strong and reliable copper joints for their specific needs through torch brazing and soldering.