Torches Used In The Plumbing Industry & How To Solder, Braze and Weld Fittings & Pipes

Learning how to use a torch is an essential skill in the plumbing industry. Knowing the correct types of torches, fuels and techniques is the key to doing a good job in a minimum amount of time and producing joints that will be reliable and trouble free.

There are three basic types of torch techniques. Soldering, brazing, and welding. For each type of bond, there is a specific type of torch and knowing which to use for a specific task is essential. Torches come in many different types, and use a variety of fuels, and a multitude of accessories but there are three basic types that you need to be familiar with.

1) Propane torches.

Propane torches are the most common type and are used by professionals and DIY homeowners alike. These torches are inexpensive and easy to use Professional plumbers often upgrade the torch assembly to a higher quality torch head with interchangeable tips, and a regulator to control the gas pressure.

Propane ( LPG) torches reach temperatures up to 3623 degrees Fahrenheit. A major advantage is that propane is available in small disposable steel cylinders that require no special storage.


This type of torch is used to join copper plumbing pipe, tubing and fixtures. This technique is referred to as "sweating", and is a relatively easy skill to master. Propane torches are available at any plumbing supply store. You will also need solder, sandpaper, flux, and a fuel tank. Propane torches come in beginners kits, but professional plumbers usually purchase upgraded torches, regulators and a variety of tips to suit specific jobs.

How to Sweat a Joint

This is the most common type of plumbing joint. It is used to add piping for a new fixture, repair a leaky valve or replace older pipes.

The first step is to turn off the water supply and make sure all parts are perfectly clean using steel wool or light grit sandpaper. Once clean, coat the parts with flux where the solder will flow. Flux is a paste that prevents oxidation of the joint while heating and enables solder to flow freely. Fit all pieces together to ensure a good fit before you begin heating the parts. Next, light the torch and set it to a low flame which you can gradually increase as you proceed. Once this is done, apply heat to the joint and begin applying the solder to the point where the two parts meet. As the solder melts, it will wick into the joint filling the gap. Your joint needs to be hot enough for the solder to flow freely or the joint will fail. Complete the joint by wiping the excess solder off with a cloth. Caution-the solder is still hot!

The links below are good resources:

How To Solder A Pipe

Soldering of No-Lead Copper Alloy Fittings, Valves and Components

How to Solder Copper Pipe (Important Tips!!)

2) Brazing torches

Brazing is similar to soldering , but requires higher temperatures and instead of solder, a brass rod is used. The torches are more complex and can use acetylene gas, or Mapp gas ( a modified type of propane). Brazing is used to join brass to brass, copper to copper, or copper to brass. Instead of solder, brass rod is used as well as flux to prevent oxidation from contaminating the joint. This technique produces a stronger joint than sweating with solder, and requires greater skill to do well. It is best to have an experienced partner show you the techniques before attempting this on your own. Brazing is also used for HVAC repairs to cooling coils and feed lines to the air conditioning unit, but this is not something for the amateur.


Brazing is used to make stronger joints than is possible with soldering. This is necessary when high temperatures or pressures will be encountered as in fire extinguisher systems, or high pressure cooling lines in air conditioning systems. Brazing requires higher temperatures and Acetylene or MAPP gas is the fuel used as propane will not generate enough heat.

How to braze a joint

The basic technique is similar to soldering, but the temperatures are much higher and the material used is brazing rod instead of solder. Brazed joints are not wiped like soldered joints as the pipe is too hot, but as brazing rod does not run as freely as solder , wiping is not necessary.

The link below will give you an idea of the basics of brazing:

My DIY Brazing Refrigerant

TurboTorch - Copper Pipe Brazing Demonstration

3) Mapp Gas Torches

Mapp gas became very popular due to its higher temperature and the ability to braze without the need for oxygen. It is also used with a new type of torch known as the Turbo Torch. This torch is simple to operate, but produces higher temperatures than propane.

Mapp gas torches can be used to solder and sweat copper, braze copper and brass and offer the convenience of a single tank system with the advantage of higher working temperatures. Work will proceed faster because the metal is heating faster.

The links below show Mapp gas being used in brazing tubing:

How to solder copper pipe tubing with a MAPP gas torch

4) Oxy Acetylene Welding torches

Oxy acetylene mixes pure oxygen with the acetylene gas to promote higher combustion temperatures. This can be in excess of 6,000 degrees which is hot enough to melt iron. This type of torch has limited use in everyday plumbing work, but there are cases where high temperatures are needed as in welding, or loosening heavily rusted pipes. Oxy acetylene welding is a true weld, which means that the metal parts are literally fused together by melting them. A filler rod made of metal similar to the parts being joined is used. This type of welding produces the strongest joint possible.


Oxy acetylene torches burn very hot and could easily burn through most copper and brass piping so using this type of torch requires greater skill than propane, acetylene, MAPP gas or other fuel types. This technique can be used to repair cast iron drain pipes where the high heat is required. This type of torch can also be used to free frozen , rusted joints in galvanized threaded pipe and with a cutting attachment, can literally cut out the old damaged piping.

How to use an oxy acetylene torch

Great care must be used with this equipment, and it is highly recommended that you seek professional help before trying it on your own.

The first step, just setting up the torch and tanks must be done very carefully as the gas is under great pressure. Equipment, hoses and regulators must be inspected for damage before each use.

The video below will give you a brief view of what is involved.

Welding cast iron

Cast Iron repair, oxy/acetylene welding

Lighting an acetylene torch

Oxy-Acetylene Torch Setup and Lighting a "How-To" Article

This is only the beginning of the many types of torches, fuels and materials available to today's tradesman or woman. The most important thing to remember is to use the appropriate type of torch for the job and to seek advice before beginning. Even experienced trades persons with many years of experience will find that the technology is always changing with new improvements to increase productivity and the reliability of your work.