Selecting An Oxy-Acetylene Welding Rig
Oxy-acetylene welding rigs come in sizes based on the capacity of the oxygen and acetylene cylinders, which hold from 10 to more than 400 cubic feet. Be sure to get regulators, valves, and hoses that match the cylinder sizes you select. Unless you expect to use the equipment a great deal, 20 cubic feet each of oxygen and acetylene—enough to weld for one hour or cut for 20 minutes—is ample. You can buy the equipment at welding-supply stores or rent it from tool-rental agencies, usually listed in directories under “Welding Equipment—Renting.” If you buy the equipment, the tanks may be empty when you get them. Fill them at a welding-supply shop.
When you rent an oxyacetylene rig you can usually obtain welding or cutting tips in a range of sizes for different metal thicknesses. Buying tips individually can be confusing, since each of the dozens of tip manufacturers uses a different numbering system. To buy the correct size, you must consult a size chart for a specific brand. The same chart prescribes the pressure you need to set on the oxygen and acetylene gauges for each size tip.
Anatomy of an Oxyacetylene Rig
Two cylinders—a tall one containing oxygen and a shorter one containing acetylene—stand on a two-wheel hand cart. They’re chained together to keep them from tipping over. You open the acetylene cylinder’s valve with a T-wrench on top, and the oxygen cylinder’s valve with a knob. When not in use, screw the protective cap onto each valve.
At the side of each valve, a dual regulator with two gauges measures the pressure in the cylinder and the working pressure in the hose. The T screw on the front of each regulator adjusts the working pressure. Separate hoses—a red one for acetylene and a green or black one for oxygen—carry the gases to the torch (inset), where an oxygen valve and an acetylene valve control the proportion of each gas at the tip of the torch.