How to Solder Copper Pipe Without Flame – Full Guide

Because of its unique characteristics, copper has been used in numerous industries for thousands of years.

How to solder copper pipe without flame

Copper was categorized early in history as a natural metal, which is found naturally in its pure metallic state.

It was used for its malleability and formability, as well as its color. As a result, copper became one of the first metals used for construction.

How is Soldering Copper Pipes without Flame Beneficial?

Soldering is done to fix the copper with other materials or to help it form a specific shape to be used for its intention.

In order to solder copper pipe without flame, the filler metal must be melted, and heat energy must be applied uniformly over the whole soldering zone.

A particular temperature-time profile is followed, which includes the stages listed below:

  1. The flux is melted
  2. The surface is activated
  3. Soldering is done, or the filler metal is melted
  4. The solder is molded, and the filler metal of mating surfaces is prepared
  5. The soldering gap is filled with solder or filler metal.
  6. Solder or filler metal is used to fill the soldering/brazing gap.

Due to economic considerations, the holding time at the soldering temperature is generally limited to the time required to produce a consistent temperature across the assembly.

The assembly is permitted to cool in still air at ambient temperature or under-prescribed cooling conditions after a reasonably short holding period. The soldered metal hardens during this time.

Methods to Solder Copper Pipe without Flame

Flame soldering (also known as torch soldering) is a type of soldering that can be done by hand or by machine.

A flammable gas flame provides the heat (e.g. acetylene). A pressure regulator directs the gas to the torch head. The type of torch to use is determined by the workpiece, material, and gas utilized. The initial step is to add flux to the surfaces that will be connected.

The joint gap must be properly dimensioned. To avoid sliding, the pieces to be soldered or brazed must be secured in place.

Flame soldering is an easily automated process and has low equipment costs, but working with a flame has its drawbacks, including how the components must be held in place using a jig and how the after-treatment of the copper takes time.

This is why it is easier to solder copper pipes without flame.

Soldering processes without flame are characterized in a variety of ways, including the heating method (energy source) employed. Other categorization systems are based on the following criteria:

  • Method of oxide removal (e.g., soldering/brazing in a protective gas environment, vacuum soldering/brazing, flux-assisted soldering/brazing)
  • Method of filler metal application (e.g., dip soldering/brazing, soldering/brazing with filler metal applied to the joint)
  • The technique of soldering/brazing the joint (manual, semi-automatic, or completely automated soldering/brazing)

1. Soldering Iron

Hot-iron soldering is a soldering technique that uses a solid medium to provide heat energy.

The solder is melted and the junction is heated by using a hot iron that can be handled manually or by a machine. Narrow-gap joints with significant overlap zones are not suited for hot-iron soldering.

A built-in electrical heating element or a tiny tank carrying a flammable gas such as natural gas, acetylene, or propane are found in most soldering irons.

The soldering iron’s heat capacity and form, as well as its tip (also known as the ‘bit’), must be appropriate for the soldered assembly.

2. Dip Soldering

The copper pies to be soldered without flame are cleaned mechanically and positioned. The assembly (‘workpiece’) is then fluxed before being immersed into a bath of molten solder or filler metal.

The dipping bath should be heated to between 55 and 100 degrees Celsius above the solder or filler metal’s liquids temperature.

3. Wave Soldering

Electronic components are soldered onto printed circuit boards via wave soldering to solder copper pipes without flame.

The last procedure includes cooling the PCB assembly in the cooling zone, either naturally or artificially, under ambient circumstances.

The PCB assembly is ideally drawn over the surface of the solder slanted at a 7° angle, according to experience. Wave soldering is a subset of drag soldering.

4. Drag Soldering

In drag soldering, the solder is applied by immersion in a static solder bath rather than by contact with the solder wave.

The angle at which the assembly enters and exits the bath is normally between 8 and 10 degrees, and the immersion depth is usually around half the PCB thickness. The oxides (‘dross’) on the surface of the solder bath are removed with a stiff strip.

Furnace soldering or brazing is almost always done in a protective gas environment or in a vacuum; it is only done in an air atmosphere on rare occasions.

5. Reflow Soldering

In the electronics industry, reflow soldering is a crucial process requiring soldering copper pipe without flame. Surface-mounted components are commonly attached to printed circuit boards using this approach.

Soldering heating modes of solder pastes comprising, for example, SnAgCu or SnAg alloys are used in this procedure. The solder in the solder/flux paste melts in a reflow oven, forming a physical connection between the electrical components and the circuit board.

6. Electric Resistance Soldering

Copper, brass, unalloyed steel, and aluminum are common parent metals used in this process to solder copper pipe without flame, although they can be used to solder or braze any metallic substance.

Before soldering or brazing, a filler metal solder is added to or put in the assembly gap. Electrodes (made of tungsten, for example) are used to push the mating surfaces together.

The electric current running in the transformer’s secondary circuit creates a lot of heat at the point of contact between the two pieces to be connected, melting the solder.

7. Induction Soldering

In induction soldering, a single-turn or multi-turn water-cooled induction coil surrounds the clean joint to solder the copper pipe without flame.

All types of metal may be joined by induction soldering or brazing, which generally employs a flux in an air or controlled environment. Copper, brass, steel, and aluminum are the most common materials utilized in this method.

The solder or brazing filler alloy chosen should have a limited melting range or a set melting point, as well as acceptable flow characteristics.

8. Electron Beam Soldering

This process of soldering copper pipe without a flame is usually done in a medium or high vacuum environment.

High power densities and a narrow beam diameter distinguish it from the other soldering techniques.

The electrons are accelerated by the strong electric field created by the high voltage (15–75 kV) placed between the cathode and anode.

Through a hole in the anode, the electron beam leaves the beam generator.

When the tightly packed electron beam strikes the target material, the fast-moving electrons’ kinetic energy is transferred to thermal energy, causing the substance to heat up.

Soldering copper pipe without flame

9. Arc Soldering

MIG or TIG soldering can be used for soldering copper pipes without flame through electric arc soldering.

An arc is formed between a wire electrode and the brazed components, which converts electrical energy into heat at the soldered junction.

Typically, the filler metal is a copper-based alloy wire or rod with a melting range lower than the parent metal.

10. Laser Beam Soldering

While both laser beam soldering and brazing processes are utilized in the automobile sector, laser beam brazing is used the most.

The technology allows high temperatures to be attained, making it possible to process high-melting copper-based filler metals easily.

A highly concentrated laser beam generates high power densities, but only a tiny heat-affected zone is created.


Soldering, like welding, is a significant process for thermally connecting materials such as metals.

Copper pipes have become a standard part of housing and commercial buildings. Flaming has been a traditional way to solder the pipes.

However, this guide has shown you how to solder copper pipes without flame and still make good use of the material.