Oxy-acetylene torches mix oxygen and acetylene from separate cylinders through regulators and hoses into a torch with a mixing chamber and tip. Welding torches melt and join metal; cutting torches add a high-pressure oxygen jet to sever metal. Use color-coded hoses, two-gauge regulators, and safety devices such as flashback arrestors. Keep acetylene working pressure low and follow manufacturer and workplace safety rules.

What an oxy-acetylene torch does

An oxy-acetylene torch mixes oxygen and acetylene gas to produce a high-temperature flame for welding, brazing, heating, and cutting metal. The fuel (acetylene) and the oxidizer (oxygen) come from separate cylinders and meet in the torch where the operator controls the flame.

Main components

  • Cylinders: separate tanks for oxygen and acetylene, usually transported on a wheeled cart and secured upright with valve protection caps. Cylinders contain different pressures and must be handled per manufacturer guidance.
  • Regulators: each cylinder uses a regulator that reduces cylinder pressure to an adjustable working (delivery) pressure. Most regulator assemblies have two gauges: one shows cylinder (storage) pressure and the other shows delivery pressure. Gauges are typically calibrated at 70°F (21°C).
  • Hoses and connections: two flexible hoses run from the regulators to the torch. In the U.S., oxygen hoses/attachments are green and acetylene (fuel) is red. Modern installations include check valves and flashback arrestors to prevent reverse flow and flame travel into the supply lines.
  • Torch body and tip: the torch has valves to control gas flow, a mixing chamber where oxygen and acetylene blend, and a tip or nozzle where the flame issues. Tips vary by application and metal thickness.

Welding torch vs cutting torch

  • Welding torch: designed mainly to melt and fuse metal. It mixes oxygen and acetylene in a relatively simple body and uses tips sized for the welding task.
  • Cutting torch: built for piercing and severing metal. It usually has a heavier, often right-angle head, a separate valve and passage for a high-pressure oxygen jet used to oxidize and blow away molten metal, and an actuator (lever or trigger) to release the cutting oxygen.

Safety and best practices

  • Keep acetylene working pressures low: acetylene is unstable under high pressure and should not be used above about 15 psi for torch work. Store cylinders upright and secure them during use and transport.
  • Use flashback arrestors and check valves between the torch and each regulator to reduce the risk of flame or pressure reversal.
  • Inspect hoses, regulators, and fittings for leaks and wear before each shift. Tighten connections and use approved gas-specific fittings.
  • Follow current manufacturer instructions and local regulations for cylinder handling and personal protective equipment (PPE), including welding goggles or helmets rated for gas welding and cutting.

Quick troubleshooting tips

  • A popping or hammering sound may indicate a flashback - shut off gas, close cylinder valves, and follow your shop safety procedures.
  • A smoky, soft flame can mean improper fuel/oxygen balance or a clogged tip - clean or replace the tip and adjust pressures/mixture.
Oxy-acetylene systems remain versatile for field work and fabrication. Respect the equipment limits, keep safety devices in place, and follow current standards and manufacturer guidance for safe operation.

FAQs about Acetylene Torch

What’s the main difference between a welding torch and a cutting torch?
A welding torch is built to melt and join metal with an oxy-fuel flame. A cutting torch has a heavier head and a separate high-pressure oxygen jet (activated by a lever) that oxidizes and blows away molten metal to sever the workpiece.
Why are there two gauges on a regulator?
One gauge shows the cylinder (storage) pressure so you know how much gas remains. The other shows the delivery (working) pressure that the regulator supplies to the torch; you adjust this for the job.
What color are the hoses and why?
In the U.S., oxygen hoses and fittings are green and fuel (acetylene) hoses are red. Color coding reduces the risk of connecting the wrong gas and improves safety.
What safety devices should be installed on an oxy‑acetylene setup?
Install check valves and flashback arrestors between the torch and regulators to prevent flame or pressure from traveling back into hoses and cylinders. Also use cylinder caps, secure cylinders upright, and inspect components routinely.
What is the safe working pressure for acetylene in torch applications?
Acetylene should be kept at low working pressures; the commonly accepted maximum working pressure for torch use is about 15 psi to avoid the risk of acetylene instability and decomposition.