What Is Oxy-Acetylene Welding? All You Need to Know

Introductory Guide to Oxy-Acetylene Welding

There are various welding processes available for fusing metal, including FCAW welding, GMAW/MIG welding, GTAW/TIG welding, SMAW welding and oxy-acetylene welding. Each welding process serves a specific purpose depending on the environment and types of materials being welded.

Oxy-acetylene welding, a type of gas welding also known as oxyfuel welding, is primarily used for welding thin metal sections and can also be used for heating tasks. Welding with oxy-acetylene is a flexible and forgiving process, making it suitable for amateur and part-time welders. Oxy-acetylene welding uses a high-heat flame produced by burning acetylene mixed with pure oxygen to melt the base material and filler rod. Oxy-acetylene welding equipment includes cylinders, regulators, hoses, torches, tips and safety valves, and it is important to follow safety precautions and guidelines when using this welding process.

You can also use oxyfuel welding for heating tasks, like releasing frozen bolts and nuts, heating heavy stock for bending and soft soldering tasks.

Juan Baltazar, Program Manager for Education and Development at Universal Technical Institute (UTI), provides insight into the oxy-acetylene welding process and the equipment used to get the job done.

How Does Oxy-Acetylene Welding Work?

Oxy-acetylene welding uses a high-heat, high-temperature flame that is produced by burning a fuel gas (acetylene) mixed with pure oxygen. So, how do you weld with oxy-acetylene? The base material is melted with the filler rod using a flame through the tip of the welding torch (commonly called oxy-acetylene torch welding).

The fuel gas and oxygen gas are stored in pressurized steel cylinders. Regulators in the cylinder reduce gas pressure.

Gas flows through flexible hoses, with the welder controlling the flow via the torch. The filler rod is then melted with the base material. However, melting two pieces of metal is also possible without the need for the filler rod.

Oxy-Acetylene Welding vs. Other Welding Process

The main difference between oxyfuel welding and arc welding techniques like SMAW, FCAW, GMAW and GTAW is the heat source. Oxyfuel welding uses a flame as the heat source, reaching temperatures up to 6,000 degrees Fahrenheit.

Arc welding uses electricity as the heat source, reaching temperatures of roughly 10,000 F. Either way, you’ll want to be careful when welding around any type of scorching temperatures.

In the early days of welding, oxyfuel welding was used to weld thick plates. Today it’s almost exclusively used on thin metal. Some arc welding processes, such as GTAW, are replacing the oxyfuel welding process on thin metals.

What Is Typical Oxy-Acetylene Welding Equipment?

Oxyfuel welding basic equipment includes the following:

• Cylinders: Steel pressurized cylinders contain oxygen and fuel gas.
• Regulators: The flow of gas needs to be controlled. Regulators take high pressure and reduce it to a lower working pressure.
• Hoses: Nonporous hoses are used to move the oxygen and fuel gas to the torch. To prevent the wrong hose from being installed or set up incorrectly, the oxygen hose is usually green, and the fuel gas hose is usually red.
• Hose fittings: Siamese hoses are one piece made of two hoses that have been molded together. Hoses can also be taped together. Oxygen hoses have right-hand threaded fittings. Fuel-gas hoses have left-hand threaded fittings. Hose connections shouldn’t leak after they’re tightened. Regulator-mounted and torch-mounted flash arrestors should be used on oxygen hoses and fuel hoses. Regulator-mounted flash arrestors stop flashbacks and backfires from entering the hoses and, potentially, the cylinders.
• Safety valves: Safety valves keep the flow of gas going in one direction, preventing gas from flowing back into the wrong line or cylinder. They also reduce the possibility of a flashback.
• Torches: Torches may vary in design, but all are made to provide complete control of the flame.
• Tips: Because there’s not an industrial standard system for identifying tip sizes, welders need to master various tip sizes. Tip sizes are comparable to numbered drill sizes. There are some torch sets where each tip has its own mixing chamber.

With Any Type of Welding: Safety First

Like all types of welding, safety is very important with oxy-acetylene welding. Juan says aspiring welders should learn about safe oxyfuel setup and system testing procedures before welding.

It’s important to refer to the manufacturer’s operating instructions and safety recommendations for how to handle gas cylinders, how to mix the gases and proper use of oxyfuel torches and tip sizes. Juan says it’s also important to understand the proper use of the following welding gases:

• Acetylene
• Methylacetylene-propadiene stabilized gas (MAPP™)
• Propylene
• Natural gas
• Propane

To ensure safety, Juan says welders should be familiar with the welding safety standards outlined by the American Welding Society, ANSI Z49.1:

• Protect the eyes, ears, head, hands, torso and feet from burns.
• Check the area for combustible materials.
• Make sure everyone around has proper personal protective equipment (PPE).
• Always know what direction the torch/flame is pointing.
• Follow the proper setup and tear-down procedures.

“Welders are exposed to hot metal, bright lights and noxious fumes every day,” Juan says. “Many jobs involve working around heavy equipment that can cause serious injury if the proper safety precautions aren’t followed.”

Train To Become a Welder: UTI’s Welding Training School

If you’re interested in learning about welding, UTI’s Welding Technology program can teach you the skills you need to pursue a career in the industry.¹ Juan says the following skills are used in welding:

• The ability to understand technical plans, drawings and blueprints.
• Manufacturing capabilities.
• Attention to detail and the ability to spot flaws and defects.
• Basic math skills with the ability to calculate dimensions and take accurate measurements.

The UTI welding program covers both oxy-acetylene welding and arc welding techniques. Students graduate prepared for entry-level welding roles in the construction, structural, pipe and fabrication industries.

“Aspiring welders should consider both the demands and the opportunities welding presents,” Juan says. “Welders need to be prepared to work in tight spaces, at elevated heights and outside in all seasons. They need to endure many hours standing or crouching and be willing to wear goggles and other safety gear.”

“Welders must be physically and mentally fit, with excellent hand-eye coordination and the ability to remain focused on a repetitive task for long periods of time,” Juan continues. “There’s currently high demand for skilled labor in the U.S.”

To learn more about UTI’s welding program, contact UTI online or call 1-800-834-7308.