Oxy-Fuel Welding & Cutting Guide

Complete oxy-acetylene guide: torch setup, cutting tip selection, regulator settings, neutral flame adjustment, cutting technique, heating and bending, and safety procedures.

Oxy-fuel processes use combustion of fuel gas (typically acetylene) with oxygen for welding, cutting, heating, and brazing. While arc processes have replaced gas welding for most joining work, oxy-fuel cutting and heating remain essential capabilities in fabrication shops, construction sites, and field repair operations.

The Four Oxy-Fuel Operations

Gas welding fuses metal using the heat of an oxy-acetylene flame with a filler rod added by hand. Still used for thin steel, copper, brass, and some automotive exhaust repair. Travel speed is slow compared to arc welding, but the equipment is inexpensive and doesn’t need electricity.

Oxy-fuel cutting heats steel to its ignition temperature (about 1,600F), then blasts a stream of pure oxygen through the metal. The oxygen reacts with the iron exothermically, creating iron oxide that blows out through the bottom of the cut. This only works on carbon steel and low-alloy steel. Stainless, aluminum, and cast iron don’t support the oxidation reaction.

Heating uses a rosebud tip to apply broad, even heat for bending, straightening, stress relieving, and removing press-fit parts. No other tool matches an oxy-fuel torch for controlled localized heating of heavy steel.

Brazing uses the oxy-fuel flame to heat the joint above 840F while capillary action draws brass or silver filler into the gap. Common for copper pipe, carbide tool tips, and joining dissimilar metals.

Equipment Setup

A basic oxy-fuel rig includes oxygen and acetylene cylinders, regulators, hoses, a torch body, and interchangeable tips. Cutting tips are sized by number, with each size matched to a material thickness range. A #0 tip cuts up to 3/8", a #1 handles 3/8" to 5/8", and sizes go up from there for heavier plate.

Set acetylene regulator pressure at 5-7 PSI for most cutting work (never exceed 15 PSI). Oxygen cutting pressure varies by tip size, typically 25-50 PSI for plate up to 2" thick.

Articles in This Section

The guides below cover torch setup and safety, cutting tip selection charts, flame adjustment, cutting technique for clean edges, and heating/bending procedures.

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