Acetylene welding, also referred to as “oxy-acetylene” welding, is not only a commonly-used method for welding, but also for cutting. Acetylene gas is created by mixing calcium carbide with water. Calcium carbide is a mixture of lime and coal derivatives that are formed within an industrial furnace at temperatures of approximately 2,000 degrees Fahrenheit. When acetylene and oxygen are mixed, a flame over 6,000 F is created hot enough to weld or cut just about any type of metal.
Acetylene welding equipment is much more universal than electric welding equipment. It is portable, versatile and less expensive. For those unfamiliar with the operation of an acetylene torch – such as what the proper mixture of acetylene and oxygen should be – it is necessary for someone with experience to instruct them. Working with a welding torch can be very dangerous for those who don’t know what they’re doing. But learning to weld using an oxy-acetylene torch is not difficult.
Basic Equipment
- Safety gear: Goggles or a face shield as well as a pair of flame-retardant welding gloves are essential before welding.
- Pressure vessels: Two cylinders are needed: One filled with pressurized acetylene gas and the other with pressurized oxygen.
- Hoses: Flame and oil resistant rubber hoses rated for a working pressure of 200 pounds per square inch (PSI) are needed. Hoses are usually green in color for oxygen and red for acetylene.
- Gas pressure regulators: These usually consist of two gauges; one for measuring high pressure – the gas in the cylinder – and the other for measuring low pressure, which is the gas emitted into the hose. The pressure in each cylinder is usually measured by PSI with the pressure flow adjusted using these regulators.
- Flashback arrestors: Connected between the regulator outlet and the hose, arrestors can also be connected between the hose and the torch. A flashback occurs when a flame rapidly burns within the torch and can then pass back through the hose. This usually happens when the gases are not at the proper flow rates and are slower than the flame speed. Loose connections or leaks can also lead to flashbacks. A flashback arrestor will cut off gas flow should a flashback occur; thus preventing damage to the torch or its operator.
- Torch: Consists of a handle, mixing chamber and valves to control the flow of oxygen and acetylene. The welding or cutting tip is attached to the end of the torch handle.
- Striker: This is a metal instrument containing a piece of flint that ignites your torch by creating a spark when manually activated.
- OperationAlways carefully inspect the equipment before using. Make sure all components are connected correctly and that there are no loose couplings or leaks. Also make sure flashback arrestors are in place and the proper hoses and gauges are connected to the proper gas cylinders.
Make sure the acetylene tank is kept at a constant pressure of 5 PSI. US regulations suggest to not allow the pressure to exceed 15 PSI and that you keep the oxygen pressure at 10 PSI.
Please remember to NEVER operate a welding torch without proper hands-on training from a professional.
Once the equipment has been checked and the proper nozzle for cutting or welding has been attached, you are ready to start your job. The last step is opening up the acetylene and the oxygen valves, located on the tank and handle of the torch.