Gas Welding Types 101 (Oxyfuel, Acetylene)
This guide will list five different types of gas welding. Additionally, it will point out advantages and disadvantages of Oxyfuel Welding.
In the end of the article, it will describe most commonly used type of gas welding.
Gas welding, a.k.a. oxyfuel welding, is the process of melting the edges of two pieces of metal using a gas flame, causing the molten metals to diffuse into each other, forming a solid joint after it cools. Since the development of arc welding, oxyfuel welding isn't as standard as it once was, but smaller weld shops and home workshops still rely on it.

When metals are joined with this method, oxygen and fuel gases are combined to create a high-temperature flame of about 3,200°C. The gases used with oxygen are typically acetylene, hydrogen, propylene, butane, and others. The choice of fuel gas often depends on the project type and the flame control desired (more on that later).

Because acetylene is the most frequently used fuel gas, many welders refer to the process as oxyacetylene welding. However, there are five types of gas welding, and here are the details on each of them:
Five types of gas welding and details on each of them.
1. Oxyacetylene welding
Oxyacetylene welding uses the concept of generating heat from the combustion of oxygen and fuel gas.
Processes that use fuel gases and oxygen to weld or cut metals.
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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.

2. MAPP gas welding
MAPP gas welding stands for Methylacetylene-propadiene-petroleum.
Gas mixture that is much more inert than other gas mixtures, making it safe to use and store.
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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.
3. Butane or propane welding
Butane vs Propane Torch: Choosing the Best One
Propane Torch (has a smaller head that curves inwardly) vs. Butane Torch (often small and handy, making it easier to use).
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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.

4. Oxyhydrogen welding
Hydrogen generator - Oxyhydrogen is a mixture of hydrogen (H2) and oxygen (O2) gases -
Hydrogen generator - hydrogen combines with oxygen to generate steam.
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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.
5. Oxy-gasoline welding
Oxy-gasoline metal welding cutting machine
Oxy-gasoline welding-cutting machine.
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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.

Advantages and Disadvantages of
Oxyfuel Welding
Even though oxyfuel gas welding is no longer a preferred method of welding, it has many applications in fabricating shops, automobile repairs, and various cutting and joining operations. Following are some of the pros and cons of this well-established way of welding:
The advantages of oxyfuel welding:
  • Relatively easy to learn and operate and
  • No need to hire highly-skilled technicians
  • Excellent for construction (no bulky, complicated equipment)
  • Good for welding and cutting material
  • Less expensive
  • Used to weld ferrous and non-ferrous metals
  • Adjustable flame intensity

The disadvantages of oxyfuel welding:
  • Lower flame temperature than arc welding
  • Does not have a high flux shield over the weld
  • Not as suitable for thick metals
Which is the Most Commonly Used
Type of Gas Welding?
Without a doubt, the most popular fuel gas is acetylene, and when it's mixed with oxygen for oxyacetylene welding, it produces a 3,200 degree C adjustable flame.
To adjust the flame, the welding operator changes the ratio of the volume of oxygen to acetylene.
The fumes generated during oxyacetylene welding come from the base metal, filler metal, and fluxes, but the fume levels are minimal and the temperatures produced by the process significantly lower than during arc welding.

Explore more about Different Types of Welding and Their Uses!
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