Blowtorch Welding – How To Guide

By ced •  Updated: 07/12/21 •  5 min read

Blowtorch welding is a type of welding that utilizes the use of a blowtorch, a high-temperature, external flame. The area being welded is heated up to such an extent that metal is melted and welded together. The main advantage of using this method is because of the controlled high temperature flame. This means that the heat transfer process will be much slower and therefore it will not cause damage to other parts of the metal or other materials present in close proximity.

Materials To Weld With

The most common material for blowtorching is stainless steel. Stainless steel has many different grades with each grade having different characteristics and properties. Some grades are used in food processing and have chemical properties that make them more suitable for welding than other grades.

Some materials used for blowtorching are:

Stainless steel – also called 304, 304L or 316

Brass – also called 410, 420 and 430

Copper – also known as copper-nickel alloy or CP-Ni (for brass and copper) or C-60 (for stainless steel)

Lead – known as L90Pb in stainless steel and Pb6 in brass. It is used to protect the metal from corrosion.

The Blowtorch

A blowtorch is the main tool for blowtorching. The torch should be able to stand up to the high heat that is produced by the flame. It should also have a cover and a handle. There are many different types of blowtorches available, including adjustable torches, propane torches and oxyacetylene torches. However, they all have a similar function. They are designed to produce a controlled, high temperature flame that allows for a quick and easy welding process. When choosing your torch it is important that you choose one which has been professionally tested and certified for safe use.

When using a blowtorch you must place the metal you are welding on a piece of wood or metal that will allow you to safely place the torch to the work piece. This is because when the torch is lit, it emits a lot of heat and once it is placed in contact with the metal/wood, it will start to melt and weld. It is important that you keep a good distance between your work piece and the torch. The flame that comes out of the blowtorch can reach temperatures up to 2000°C which will cause materials to burn very easily.

Before starting, always check that your blowtorch has sufficient gas pressure, as well as a good air supply for cooling down after welding. You should also ensure that there are no foreign objects in your torch, as these can often catch fire and produce a spark that will cause an explosion. When using a blowtorch it is important to always wear an appropriate protective mask and goggles.

How To Blowtorch Weld

  1. Place the blowtorch on the work piece and light it up. Ensure that you place the torch into a metal or wood holder so that you do not get burnt by the flame. Turn off the oxygen supply at this stage so that it does not become too powerful.
  2. Hold the torch at a 5-10 degree angle to the work piece. This will allow you to weld parts of larger pieces with ease and without burning through them. Try not to hold the torch directly over the work piece.
  3. Once you have the torch in place and lit, you can start welding. You need to weld a thin layer of metal onto the part that you are working on, which will eventually be covered by other layers that are welded on top of it.
  4. Keep the torch moving around so that you can weld a continuous layer onto the part that you are working on. Try not to use too much pressure when welding as this could result in cracking the metal or your work piece falling apart. If there is any resistance, then try using less pressure or remove any foreign objects from your torch before starting again.
  5. After welding has been completed, turn off the torch and allow it to cool down. Ensure that you put the torch back in the holder in order to protect you from any burns that might have been caused.
  6. Once you are satisfied with your welding, simply wash off any metal residue with a cloth and then dry it with a rag or paper towel.
  7. When the metal has cooled down, simply paint it with a protective coat of spray paint or clear lacquer so that it is not damaged by water or corrosion over time.


Blowtorch welding is quick and simple to do, meaning that there are minimal chances for mistakes to be made and for your quality of work to be affected as a result of this. It is also possible to weld different metals such as copper, zinc and aluminum together without any problems.


Blowtorching is not suitable for welding metals that are very sensitive to heat or to those that are brittle. If you are using a blowtorch for welding, always ensure that you are using the appropriate grade of metal.


Blowtorch welding is a fantastic way to weld metals together and is relatively safe and easy to use. However, it is important that you are aware of the precautions that need to be taken if you are using a blowtorch for the first time.

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