Acetylene Acetylene is used in welding torches. In pure oxygen,temperature of flame reaches2800°C. It would violently decompose to its elements,but the cylinder on the torch contains crushed firebrick wet with acetone to moderate it. Chapter 9 7Chapter 9 7 Acetylene • Acetylene is used in welding torches. • In pure oxygen, temperature of flame reaches 2800C. • It would violently decompose to its elements, but the cylinder on the torch contains crushed firebrick wet with acetone to moderate it