Acetylene is the primary fuel for oxyfuel welding. Oxyacetylene provides the highest flame temperature of the fuel gases, making it ideal for welding high-strength steels. The equipment is portable and relatively easy to use. It comprises individual steel cylinders of oxygen and acetylene gases under pressure, each fitted with regulators and hoses that lead to the mixing chamber.

Welders can adjust the flame by changing the ratio of oxygen to acetylene, creating three flame settings: neutral, oxidizing, and carburizing. Most welding occurs with the neutral flame setting, meaning there are equal quantities of oxygen and acetylene. Increasing the oxygen flow rate produces an oxidizing flame while carburizing is obtained with a higher acetylene rate.

Specially designed safety valves between the hoses and the cylinder regulators keep the gas flowing in one direction, reducing the possibility of a hazardous flashback. And because acetylene is a volatile gas, it requires careful handling and specific storage procedures.

Even though acetylene is typically the most expensive of the fuel gases, oxyacetylene welding is the top choice of many beginners and part-time welders since it is a flexible and forgiving process.

MAPP stands for methylacetylene-propadiene-propane gas welding. It is a gas mixture that is more inert than others, making it safer and easier to use than acetylene and a favorite of beginner and recreational welders. Unlike acetylene, MAPP gas is less likely to explode if the cylinder is hit or bumped. It also withstands higher pressures, making it ideal for underwater work, such as ship repairs.

MAPP gas production ended in North America in 2008. Still, MAPP substitutes containing mostly propylene, some propane, and occasionally dimethyl ether are available. Although MAPP gas flames do not burn as hot as acetylene, some welders insist it meets or exceeds the performance of acetylene in welding.

However, the hydrogen concentration in the flame infuses into the molten steel, making the welds brittle. But for small-scale welding projects, the hydrogen escapes, and MAPP can be used for welding small steel parts.

Butane and propane are similar gases that can be used individually as fuel or combined. They have lower flame temperatures than acetylene and are less costly and easier to transport.

Propane torches are often used for soldering, bending, and heating, and because propane is a heavy gas, they require a different torch tip than the injector tip. Both torches are valuable tools for welding at home, but each torch produces different temperatures: Butane reaches around 2,400 degrees Fahrenheit, while propane torches can heat to 3,600 degrees Fahrenheit.

Propane torches have a small torch head that curves inward, allowing a more concentrated flame. The closer the flame is to the workpiece, the more precise and hot it is, and vice-versa. Butane torches have straight open ends, emitting a full flame. However, butane torch triggers can emit low or high amounts of butane, enabling the welder to control the flame temperature.

Although butane torches have a weaker flame, they are more compact and portable, making them better suited for soldering metals, drying wet materials, and heat-shrinking tubing and wiring. Propane torches are primarily used for welding.

Oxyhydrogen welding combines hydrogen with oxygen to generate steam, producing a flame temperature of around 2800 degrees C. However, the weld pool has no protection from the atmosphere when the torch completely provides the combustion oxygen. So, the torch delivers a smaller amount of oxygen, and atmospheric oxygen burns the remaining hydrogen, providing a protective preheating flame to surround the main flame.

Because this protection reduces the flame temperature, oxyhydrogen welding is typically slower. Still, it is a safe and convenient process used mainly to weld thin sheets of steel and alloys with low melting temperatures. No gas cylinder is required, and there is no risk of explosion.

Oxyhydrogen welding entails fuel from water and water vapor left behind, ensuring an environmentally friendly process. Moreover, the welding work is fast, precise, and smooth, with lower energy costs than other welding processes.

Oxy-gasoline welding supplies a mixture of pressurized gasoline as welding fuel and oxygen to the welding torch.
This mixture works well as a cost-saving method to cut thick steel plates. This gasoline can be pressurized by a hand pump on the cylinder, giving more advantages to this type of welding used in more remote areas or wherever construction costs are an issue.