The gas is produced by the chemical reaction between calcium carbide and water: CaC 2 + 2H2O → C 2 H 2 + Ca(OH) 2 + heat Acetylene (C 2 H 2 ) possesses the advantage of a higher combustion velocity, higher flame capacity and higher flame temperature over other fuel gasses (propane, hydrogen natural gas). A gas with a higher combustion velocity produces a shorter flame. The flame capacity is the heat quantity in kJ (kiloJoule), which is supplied to every square centimeter of the workpiece surface per second. Acetylene oxygen are suited together in the mixing tube of the torch. The mixture ignites at 335 o C and yields. Acetylene + oxygen → 4 CO 2 + 2 H 2 O + heat One cubic meter of acetylene gas produce up to 57,000 kJ of heat. This thermal energy heats the material to the melting point and fuses it. Acetylene Cylinders are made of seemless drawn steel tubes. Even at 2 bar overpressure, acetylene tends to explode, a decomposition process which produce heat (C 2 H 2 → 2 C