An oxy-acetylene torch generates an extremely hot flame by combining oxygen and acetylene gases. Reaching up to 3,200 degrees Celsius, this flame is highly effective for cutting, welding, and heating various metals. Its portability and ease of use contribute to its widespread application. Correctly setting up this torch system is paramount for both operational effectiveness and user safety.
Essential Safety Precautions
Operating an oxy-acetylene torch demands strict safety protocols. Essential personal protective equipment (PPE) includes welding goggles with at least a No. 4 filter lens, leather gloves, and protective clothing like aprons and jackets to shield against sparks and heat. Steel-toed boots are also required for foot protection.
Ensure adequate ventilation to disperse fumes and prevent hazardous gas accumulation. The work area must be clear of combustible materials, grease, and oil, with a fire extinguisher available within 9 meters (30 feet). Gas cylinders, containing gases under high pressure, must always be secured upright, typically chained to a wall or cart, to prevent tipping, valve damage, or becoming dangerous projectiles. Valve protection caps should remain on when cylinders are not in use or during transport. Never use oil or grease on any welding equipment, especially oxygen components, as they can ignite spontaneously with high-concentration oxygen.
Key System Components
An oxy-acetylene torch system comprises several interconnected parts, each ensuring controlled and safe operation. Oxygen and acetylene are stored in separate steel cylinders under high pressure, typically black for oxygen and red for acetylene. Regulators reduce cylinder pressure to a safe, usable working pressure for the torch.
Flexible hoses connect regulators to the torch handle; oxygen hoses are green, and acetylene hoses are red, preventing accidental interchange due to their different thread types. The torch handle contains separate control valves for each gas, leading to a mixer chamber where gases combine before exiting through the tip. Various cutting and welding tips attach to the torch, selected based on the task and material thickness.
Step-by-Step Assembly and Connection
Setting up begins by ensuring cylinders are securely upright, chained to a stationary object or specialized cart. Remove valve protection caps from both cylinders. “Crack” the cylinder valves by briefly opening and closing them to clear debris; stand to the side. This prevents foreign materials from damaging regulators.
Attach appropriate regulators to their respective cylinders (oxygen to oxygen, acetylene to acetylene); each gas uses a specific thread type, preventing incorrect attachment. Hand-tighten regulator nuts, then use a wrench to secure them firmly without overtightening.
Connect the green oxygen hose to the oxygen regulator and the red acetylene hose to the acetylene regulator; oxygen hoses have right-hand threads, acetylene hoses have left-hand threads. Attach the other hose ends to the torch handle, tightening with a wrench for a secure seal. Select and attach the appropriate welding or cutting tip. Ensure all torch valves are closed.
Leak Detection and Initial Operation
After assembly, verifying the system for leaks is an essential safety step. With all connections secured and torch valves closed, slowly open the oxygen cylinder valve completely, and the acetylene cylinder valve only about one to one-and-a-half turns. This pressurizes the system, allowing for leak detection. Apply a leak detection solution, such as soapy water, to all connections, including cylinder valves, regulator connections, and hose connections. The appearance of bubbles indicates a leak, which must be addressed by tightening connections or repairing/replacing faulty components before proceeding.
Once the system is leak-free, purge the lines to remove any air or contaminants by briefly opening the torch’s oxygen valve, then closing it, and repeating for the acetylene valve. Next, set the working pressures for both gases using the regulators; consult tip manufacturer recommendations or a pressure chart for correct settings, typically keeping acetylene pressure below 15 psi. For example, cutting less than 1.5-inch thick steel suggests 10 psi for acetylene and 40 psi for oxygen.
To light the torch, open the acetylene torch valve about a quarter to half a turn, then use a friction striker. Never use matches or cigarette lighters. Slowly increase acetylene flow until the flame separates slightly from the tip and black smoke disappears. Gradually open the oxygen torch valve and adjust until a neutral flame is achieved, characterized by a sharply defined inner cone.
Proper Shutdown and Storage
Proper shutdown of the oxy-acetylene system is essential for safety and equipment longevity. Begin by closing the acetylene torch valve, followed by the oxygen torch valve, to extinguish the flame. Next, close the cylinder valves completely, starting with the acetylene cylinder and then the oxygen cylinder.
Once the cylinder valves are closed, bleed the pressure from the regulators and hoses by opening the torch valves one at a time until the pressure gauges read zero. After the gauges indicate no pressure, turn the regulator adjusting screws counter-clockwise until they are loose. This relieves spring tension and prevents damage to the regulator diaphragms during storage.
Finally, disconnect the hoses and regulators, replace the protective caps on the cylinders, and store all equipment in a clean, dry, well-ventilated area, separated from other flammable materials. Oxygen and acetylene cylinders should be stored at least 20 feet apart or separated by a fire-resistant barrier.