Cutting metal with an oxyacetylene torch takes a little care and attention. But once it’s being cut, the process is straightforward and rewarding. Oxyfuel torches use the combustion of acetylene to melt metal. The oxygen is then introduced into a jet under pressure that works by burning the steel: it melts it and makes it cut easily. Given the volatile nature of the gases used, safety is very important when using a gas-based torch.
Place your welding equipment in a free area, away from flammable objects like wood, sawdust, and paper. Working on the ground or concrete will prevent flying sparks from moving away and causing a fire. Make sure all hoses are untangled and connected to the correct valves and regulators, away from any open fires.
Check that the regulators, both oxygen and acetylene, are pointing all the way down, and that the valves on both gas tanks are closed.
To prevent damage to the regulators from high gas pressures, slowly open the valves on both tanks. At this point, vent any gas left in the hoses by opening the valves on the torch.
Turn the regulator on your acetylene tank, until you achieve a pressure of 5 to 8 PSI. Vent the acetylene valve on the torch to test the gas pressure. Close the valve and recheck your gauge to make sure the regulator is holding pressure.
Turn the oxygen regulator until you achieve a pressure of 25 to 40 PSI. Vent the oxygen valve on the torch and check to make sure the line is holding pressure. Close the oxygen valve.
Slightly open the acetylene valve and light the torch using the spark igniter. Adjust the valve until the flame is 8 to 10 inches (20.32 or 25.0 cm) and the smoke has stopped.
Open the oxygen valve on the torch. When the proper amount of oxygen is introduced, the center of the flame will turn blue. Open the valve until the blue flame begins to shrink toward the torch opening.
Adjust the acetylene valve to alter the length of the flame to be the correct size for the material you are cutting. You want it to be a little longer than the width of the material you are cutting.
Bring the flame to the edge of the metal and hold until the molten metal begins to stagnate. Squeeze the shut-off valve to release a jet of oxygen that will ignite the steel. Now you can start cutting.
Make sure all hose connections, regulators, and valves are not leaking. Gas welding relies on constant gas pressure, and leaks will hamper your welding and cause safety issues.
Never take your acetylene pressure beyond 15 PSI. May cause violent self-combustion explosion.
Wear all necessary safety gear and work carefully. A torch that is hot enough to melt metal can cause very serious injury to a user.