A torch which produces a flame by burning a mixture of acetylene and air. The flame is as easily controlled and manipulated as the oxyacetylene flame, but has a lower temperature.

The air-acetylene torch operates on the same principle as the Bunsen burner, that is, the acetylene flowing under pressure through a Bunsen jet draws in the appropriate amount of air from the atmosphere to provide combustion. The flame is adjusted by controlling the amount of air admitted to the Bunsen jet. The mixer on the torch must be carefully adjusted to draw the correct volume of air to produce an efficient, clean flame. The air-acetylene flame ignites at 480°C (896°F) and produces a maximum temperature of 1875°C (3407°F).

The air-acetylene torch is used for brazing, soldering, and heating applications, but the flame temperature is not sufficient for welding, except for joining materials with a low melting point, like lead. It is widely used for soldering copper plumbing fittings up to 25 mm (10 in.) in diameter.

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