Gas Welding

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Gas welding is a type of welding process that uses a flame that is fed by a pressurized gas fuel. Several different types of fuel gases can be used depending on application, availability, and cost. Gas welding has been actively used since the 19th century, and although it has been largely replaced by arc welding for many applications, it is still valued for its portability.

Gas Welding Basics

Gas welding operations center on a torch that creates the welding flame. The welder can adjust the amount of gas being used by the torch and the oxygen used to feed the flame. By controlling the ratio of the gas and oxygen, the welder can create different flames with different characteristics, depending on the material being welded. The welder uses a filler rod coated with flux to add material to the weld and to displace the air from the weld location. Like all welding processes, the welder must wear protective clothing, including a welding mask, gloves, and coverall clothing.

Gases Used for Welding Fuel

Before acetylene could be effectively produced and contained, coal gas and hydrogen were used for gas welding. Today, gas welding is performed using propane, MAPP, gasoline, and hydrogen. Oxy-acetylene is the most common gas combination used in gas welding operations. Oxy-acetylene welding combines oxygen gas and acetylene gas to create the flame. Acetylene provides the hottest flame of all gas welding fuels, and can therefore be used to weld or cut thicker materials. However, acetylene is more expensive than most welding fuel gases.

Welding Rods

Gas welding uses welding rods to introduce filler material into a weld. Welding rods for gas welding are coated with a flux material that vaporizes when heated. The vaporized flux displaces air from the weld location so that oxides are not included in the weld. Welding rods are available in a variety of materials to match the material of the work pieces being welded.

Pros and Cons of Gas Welding

No electricity is required to perform gas welding, so these systems are portable and can be used in remote locations that do not have electrical sources. However, the gases used for this type of welding are combustible and they must be stored and handled properly. Gas welding does not produce as much localized heat as arc welding, and the quality of welds created by arc welding have resulted in the decline of gas welding as the primary welding process. However, gas welding does still remain an important part of welding and fabrication shops