What is Oxy Fuel Welding & How It Works (The Basics)

There are many welding techniques in the world. Among them Arc welding, resistance welding, solid state welding, brazing, soldering and many more types are well known and popular. Each of them are unique in feature and purpose and all of them are very useful when it comes to effectiveness.

Therefore, there is another type of welding process that is more flexible and forgivable. And it is an oxy fuel welding process. It is also known as Gas welding or oxy-acetylene welding. Here acetylene is a type of gas that is used along with oxygen to create a flame with sufficient heat to melt and join metals.

So in short oxyacetylene welding or gas welding is a welding process where acetylene and oxygen is combusted for melting the base metal and joining metals together.

Oxy Fuel welding
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What Equipment’s Are Required For The Process?

The components that is required for oxy fuel welding are-

  • Oxygen Cylinder: Supplies oxygen under high pressure.
  • Acetylene Cylinder: Contains acetylene, a highly flammable gas.
  • Regulators: Control and regulate the flow of oxygen and acetylene from the cylinders to the welding torch.
  • Hoses: Hoses are basically nonporous in feature. It contains the gasses and reaches them to the torch for making flame. Hose must be fitted tightly without having any leakage. They can be taped together. Normally right hand threaded hoses are oxygen hose and left hand threaded hoses are acetylene gas hose.
  • Safety valves: It ensures the gas flows toward one direction preventing gas from flowing backward. It also reduces the chase of flashbacks.
  • Welding Torch: The device where oxygen and acetylene mix and burn to produce a welding flame.
  • A filler rod: Used to join the base metal with a work piece. The filler rod is melted through a welding torch and applied on the joining area of the working metals.

How Does It Work?

For oxy fuel welding, two types of gas are required. They are oxygen and acetylene. Separate oxygen cylinder and acetylene cylinder supplies the gas required for the process. There are regulators on both cylinders that control the gas pressure and a welder must control the gas flow according to the need.

When gas is released from the cylinder it goes to the weld torch tip through gas hoses. When gasses are mixed together it creates flame at the tip of the torch. That flame is so hot and strong that it melts metals of any kind that comes to its contact. By applying the flame directly on the base and work metal, you can join them together.

You may also use filler metal for joining the base metal & work piece. Here the flame would melt the filler rod and melted rod would connect the base and work piece metal together.

That’s the way metals are melted and joined together using oxy fuel weld technique.

Types of Flames

Flames are crucial in oxy fuel welding. It is produced as a result of mixture of gasses together. Flames can be of three types: Neutral flame, Oxidizing flame & Carburizing flame based on the settings and mixture of gasses.

If the proportion of oxygen and acetylene are equal, then it would create a neutral flame. If you increase the flow rate of oxygen compared to acetylene, oxidizing flame would be obtained. And while acetylene gas flow rate is increased and acetylene remains the same, Carburizing flame is produced.

oxy gas welding flames
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Welding Positions


In this position, you may travel the torch at 60-70 degree angle from left to right on the work metal. Filler metal can be positioned at 30-40 degree angle to the plates. This position of welding is used to weld unbeveled nonferrous plates.


It is opposite of leftward that means torch is hold at 40-50 degree angle and moved from right to left over the work metal. Filler rod is stationed the same as the leftward position.


Here rod and torch both are moved together from bottom to top in an oscillating way. The rod creates a 30 degree angle while the torch is moved with 25-90 degree work angle.

What Metals Can Be Welded With Oxy-Gas Welding

Almost every type of ferrous & nonferrous metals can be oxy fuel welded. You can weld Aluminum, Stainless steel, brass, bronze, Carbone steel, cast iron, magnesium, copper, nickel, mild steel and even zinc using the technique. Basically oxygen and acetylene are used to weld higher melting point metals.

For example, for welding steel, whose melting point is above 1500°celsius, must be welded with the mixture of oxygen and acetylene mix. For gas welding lower melting point metals you may use propane, coal gas or hydrogen gas.


  • The process can be applied for both ferrous and nonferrous metals.
  • It doesn’t require any electricity connection
  • It doesn’t require expensive welding machine
  • Very simple, easy and straightforward process
  • Equipment’s required for the job are cheap and easily available


  • Not suitable for thicker metal as its penetration rate and heat are lower compare to arc welding techniques
  • For aesthetic look or professional finishing on metal, this technique is not suggested.
  • It is prone to defects like porosity, crack etc. as the weld pool is not shielded.
  • It can alter mechanical properties of metals because of direct heating and temperature fluctuation.


Oxy-acetylene gas welding is a versatile and widely used welding process that finds application in various industries. Here are some common applications of oxy-acetylene gas welding:

  • Welding Sheet Metal

For bonding thinner aluminum or steel of 24 gauge sheet metal, gas welding is the best option. It reduces the risk of burn through issues in sheet metal while welding.

  • Metal Fabrication and Repair: Oxy-acetylene welding is extensively used in metal fabrication shops for joining and repairing ferrous and non-ferrous metals. It allows for the creation of strong and durable welds in materials such as steel, aluminum, and copper.
  • Automotive Repairs: Oxy-acetylene welding is often employed in the automotive industry for repairing exhaust systems, body panels, and other metal components. The portability of the equipment makes it suitable for on-site repairs.
  • Shipbuilding and Marine Repairs: Shipyards utilize oxy-acetylene welding for construction and repair work on metal structures in the maritime industry. Its flexibility in working with various metal types makes it a valuable tool for welding and cutting tasks.
  • Construction and Infrastructure: Oxy-acetylene welding is used in the construction of buildings, bridges, and other infrastructure projects too. It allows for on-site fabrication and repair of metal components, providing a quick and effective solution.
  • Plumbing and HVAC Systems: Welding copper pipes and other metal components in plumbing and HVAC (Heating, Ventilation, and Air Conditioning) systems is a common application of oxy-acetylene welding.
  • Cutting and Gouging: Oxy-acetylene welding is also employed to cut metal plates into pieces or remove unwanted sections from the work piece.
  • Brazing and Soldering: Oxy-acetylene welding is also suitable for brazing and soldering applications, where lower temperatures are required to join materials without melting the base metals.
  • Heating: Another important application of oxy acetylene welding can be heating work. For example to release frozen or rusted bolts or nuts, gas welding is used. It basically heats the rusted area, making it loose so that it can be unscrewed easily.


Oxy Fuel welding technique is very easy, portable, flexible and less costly process of welding. It requires less expertise also to do the welding on metal. Though it cannot produce the best quality weld as arc welding process, it is used widely just because of its simplicity and ease of use.

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