How to Oxy-Acetylene Weld?

How to Oxy-Acetylene Weld?

Oxy-acetylene is not actually any chemical mixture between gases but a simple combination of oxygen and acetylene gases to heat anything. Oxygen works as a great source for creating a flame, while acetylene is a good fuel gas. The mixture of them works amazingly to form both heat and light. As a result, they are often used for cutting or welding sheet metals.

Oxy-acetylene welding is a type of basic gas welding, which makes use of two gases and a filler rod. These types of welding require numerous practices and trials to gain perfection. Since you can weld pretty much any metal type with it, it’s one of the most popular welding techniques out there. We will explain how to oxy-acetylene weld properly in this article.

How Oxy-Acetylene Weld Works?

In an oxy-acetylene welding set-up, there will be two gas cylinders for two gases. They stay connected to a torch or blowpipe. You can change the psi of the gases by turning the valves. You will need to change the ratio between the gases for a suitable heating and flame height. People mostly use a temperature of around 3200-degree C. This level of temp is enough for most metal types you can come across.

Oxy-acetylene is a side-by-side welding technique. It means that the metals welded will be connected to their edges. You will use the flame to heat both edges and fuse them together with the help of filler material.

Oxy-acetylene Welding Instruments

Below is the equipment necessary for Oxy-acetylene welding. They should give you a clearer idea of the whole system.

Gas Cylinders- There will be two gas cylinders. The black one is oxygen, and the maroon one is acetylene. Before welding, both cylinders should be sealed properly to prevent leaks.

Pressure Regulators- It is to control and keep track of the gas flow. They may be designed differently for various gases so, choose them carefully. Also, never use a damaged regulator.

Flame arrestors- Also known as flashback arrestors, they are to prevent any flashback flames. They stay in-between the hose and cylinders. Flames may appear in flashbacks, and these arrestors don’t let them happen.

Hoses- The two hoses for oxygen and acetylene will be attached between the cylinders and the torch. They should be fastened, and no leakage must happen. Hoses also have valves to control the gas flows inside them.

Welding Torch- This is the instrument that you basically hold on the metals to weld. It’s a torch where the gases mix. The amount of each gas can be controlled using the valve on the torch. They create the light and flame at the nozzle tip. You will place this tip on the metal edge for the welding process.

Economizer- It is a tool that stops the wasting of gases. It will extinguish the flame automatically when the torch is not in use. To re-ignite it, take the torch off the lever rod, and go for the pilot light. It’s a great device to save some valuable resources and money.

Lighting Up the Torch

  • Open the valves of both gases slowly and carefully.
  • Set the regulator to the correct pressure (10 psi for acetylene and 40 psi for oxygen). Turn the valve on the torch/blowpipe too.
  • Use a striker at the correct angle to light up the torch. Avoid liquid lighters.
  • Adjust the acetylene gas until the fire is smokeless.
  • When there is no smoke anymore, use the control valve to increase the oxygen flow to the blowpipe. Make sure that the final flame has a white inner-cone with a sharp shape.
  • To weld nickel or high-carbon steel, go for a carburizing flame, where the acetylene has more supply than regular flames.
  • To weld copper, brass, or bronze, choose an oxidizing flame. They have a higher oxygen supply.
  • A neutral flame is suitable for most steel types. It has an equal supply of both gases.

Welding Process

There are several oxy-acetylene welding techniques available. We are going to talk about the four most popular ones below-

Leftward Method

For steel sheets with a thickness of up to 5 mm, the leftward method is the ideal technique. As the name suggests, the welding will be moving from right to left as you hold the torch in your right hand. Pay attention to these steps during the welding session.

  • Move side-to-side gradually at the edge to let the metal heat evenly and properly.
  • Angle the filler rod so that it stays in front of the nozzle.
  • Heat the metal edge to form a weld pool. Dip the filler rod in the molten weld pool to melt it.
  • Avoid keeping the filler rod in the molten weld pool continuously.

Rightward Method

Suitable for steel plates of over 4 mm, the rightward oxy-acetylene method is almost similar to the leftward technique. In this way, the weld and the filler rod will move from left to right. Hold the blowpipe on your left hand. You will need to follow the same steps mentioned in the leftward method. The filler rod will run forward in a round motion, and the blowpipe will go along the weld seam.

The vertical method is necessary when two opposite edges of a steel plate need to be welded simultaneously. Following the same principles as the previous two methods, the weld will go from the bottom of the edge to the top.

Bronze Welding

When you need to weld copper, you need to follow some special steps. Firstly, bronze welding requires rods made of bronze alloys. Be careful not to melt the edge of the metal. Instead, heat them until they get a red color.

Frequently Asked Questions

What Metal Can I Weld with Oxy-Acetylene Welding?

Almost all commercial metals are suitable for oxy-acetylene welding. People mostly weld low-carbon steel, alloy steel, cast iron, or copper using this method.

What PSI Should I Set the Oxygen and Acetylene at?

For most cases, it is 40 psi for oxygen and 10 psi for acetylene. But it may depend on the application.

Final Note

Even though Oxy-acetylene welding may seem easy while reading the techniques, it actually takes a lot of practice to be good at. Not to mention, you should be extra careful the whole time to avoid any accidents. For example, wear protective wears and make sure to be slow when turning the valves.

Also, before the welding begins, you must double-check everything. The most common hazards with this welding are burns, flashbacks, fire explosions, asphyxiations, and leaks. Try to turn off all gas supplies if any accident occurs.

Last Updated on 2 years by Richard Boyer

  • June 8, 2022
Richard Boyer

Richard Boyer has been a professional welder for over 27 years of his life, and now he is a trainer and blogger providing critical information to anyone interested in welding. He is helping out both hobbyists, novice and professional welders to learn newer and better techniques. Read more about me

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