An oxy-acetylene torch uses a controlled flame from the combustion of oxygen and acetylene gases. This device functions to cut, weld, braze, and heat different types of metal. The torch operates by mixing the two gases, which are then ignited at the nozzle to create a concentrated flame.
The oxy-acetylene torch produces one of the hottest common torch flames available. This flame can reach temperatures ranging from approximately 3,500 to 6,300 degrees Fahrenheit (1,930 to 3,500 degrees Celsius). This heat results from the combustion of acetylene in pure oxygen.
The precise temperature varies based on several factors. The ratio of oxygen to acetylene is important, as different gas mixtures create distinct flame types. For instance, a neutral flame, with a balanced oxygen-to-acetylene ratio, typically burns around 5,720 degrees Fahrenheit (3,160 degrees Celsius). The purity of the gases and the design of the torch tip also influence the flame’s intensity and temperature.
The high temperatures of an oxy-acetylene torch stem from a chemical reaction: the combustion of acetylene (C2H2) in pure oxygen (O2). Acetylene is a potent fuel gas. Oxygen, a powerful oxidizer, enhances this combustion, allowing for a hotter and more concentrated flame than acetylene burning in air alone.
Combustion occurs in two stages within the flame. The primary combustion takes place in the inner cone, where acetylene and a portion of the supplied oxygen react to form carbon monoxide and hydrogen gas. This initial reaction, which is exothermic, produces the flame’s highest temperature, often reaching around 6,000 degrees Fahrenheit (3,320 degrees Celsius) at the tip of this inner cone.
Next, a secondary combustion occurs in the outer envelope of the flame. Here, the carbon monoxide and hydrogen from the primary reaction combine with additional oxygen from the surrounding air to oxidize into carbon dioxide and water vapor. This two-stage process ensures a complete release of heat.
Applications
The heat generated by an oxy-acetylene torch makes it a useful tool across industrial and artistic applications. Its versatility allows for various processes that manipulate metals. These applications include welding, cutting, brazing, and heating.
In welding, the torch’s high temperature melts the edges of metal pieces, fusing them together, often with a filler rod. This method joins thin metal sections, performs repairs, and creates intricate metal artwork. The torch is also used for cutting, where it heats metal to its ignition temperature before a stream of pure oxygen is introduced to burn and remove the material, allowing for precise cuts in steel and other alloys.
Brazing involves joining two or more metal items by melting and flowing a filler metal into the joint, which has a lower melting point than the base metals. This technique is used for joining copper, brass, and bronze components. The torch’s heat is used for heating tasks, including softening metal for bending and shaping, loosening rusted fasteners, and preheating materials. Other applications include flame gouging for creating grooves and flame cleaning for removing surface contaminants.
Safety Precautions
Given the temperatures and the use of pressurized, flammable gases, adhering to safety protocols is essential when operating an oxy-acetylene torch. Neglecting these precautions can lead to severe burns, eye damage, explosions, or other serious incidents. Proper training and a thorough understanding of the equipment are necessary before any operation.
Personal protective equipment (PPE) is essential for safety. This includes wearing welding goggles or a face shield with a minimum Shade 4 filter lens to protect against light and infrared radiation. Welding gloves, flame-resistant clothing, a leather apron, and safety shoes or boots are also necessary to shield against heat, sparks, and molten metal. Adequate ventilation in the work area helps disperse fumes and prevents gas accumulation.
Safe handling and storage of gas cylinders are important. Both oxygen and acetylene cylinders must be stored upright and secured with chains or straps. They should be kept in a cool, well-ventilated area, away from heat sources or flammable materials. Oxygen and fuel gas cylinders must be separated by at least 20 feet or by a fire-resistant barrier.
Flashback arrestors are important safety devices, which should be installed on both the oxygen and acetylene lines at the torch or regulator. These devices prevent the flame from traveling back into the hoses and cylinders, reducing the risk of explosions. They typically incorporate check valves to stop reverse gas flow and flame filters to quench any flashback. Users must also avoid using oil or grease on any oxygen-related equipment, as these substances can ignite in the presence of pure oxygen.