Gas welding, also known as oxy-acetylene welding or simply acetylene welding, uses a gas-fed torch to create the heat necessary to make a weld. Gas welding is considered to be very beginner-friendly, since welders have control over the intensity of the flame — though proper welding procedure must still be followed. Taking the time to properly prepare for gas welding increases the success rate of the welds you make.
Preparing the Materials
Before you can begin welding, it’s important that the materials you will be using are properly cleaned and prepared. Clean the torch nozzle and other torch components, and also the metal you will be welding. Remove any carbon deposits that may have built up in the nozzle. Clean the metal that will be welded, brushing it with a steel-bristled metal brush to remove any particles that could interfere with the weld. You should also position the metal during the preparation phase and secure it with clamps.
Assembling the Welding Torch
The welding torch needs to be assembled by hand to prevent damage that could be caused by over-torquing with tools. Check the gas pressure in the oxygen and acetylene tanks, making sure that there is oxygen in the tank and that the acetylene tank registers at least 50 pounds per square inch of pressure. Connect the nozzle you are using to the torch, then connect the gas lines.
Starting and Adjusting the Flame
After assembling the welding torch, you’re ready to start the flame. Turn the main valve on the acetylene tank approximately half a turn, then open the pin valve on the torch to keep the acetylene from building up too much pressure. Adjust the regulator valve until you have 5 PSI of pressure, and close the pin valve; then open the main valve on the oxygen tank. Open the oxygen pin valve just like you did with the acetylene, adjusting the regulator valve on the oxygen tank until you have 10 PSI before closing the pin. Open the acetylene valve just enough to let gas start to escape.
Once you have the gas properly regulated, you can light and adjust the flame. Use a gas striker to light the torch, then let more acetylene flow until the flame of the torch is barely touching the nozzle. Open the oxygen pin valve slightly to introduce oxygen to the flame’s fuel, causing the flame to turn blue.
Making the Weld
Wear a welding mask to protect your eyes, and also wear heavy gloves. Use the tip of the torch’s flame to heat the metal you intend to weld, letting it begin to glow. Make sure that the flame is applied evenly to both parts of the metal, and continue heating it until small pools of molten metal appear on both parts. Move the flame around the molten metal to mix the two pools together, creating what will become the actual weld. Keep moving slowly along the weld line, mixing the pools to weld the entire length of the line.
Shutting Down the Torch
Once you have finished a weld, you can shut off the torch and disassemble it. Close the pin valve for the oxygen line first, then the valve for the acetylene to turn off the flame. Close the main valve on the oxygen tank, and fully open the regulator valve; then repeat the process for the acetylene tank to remove all of the gas from the gas lines. The lines can then be removed from the torch, and the regulator valves closed.