Acetylene Industrial grade 2.5 (99.5%). A hydrocarbon fuel gas widely used in metal fabrication for oxy-fuel welding, cutting and heating. Producing the hottest and most concentrated primary flame of all fuel gases, acetylene is the fuel of choice for repair work and general cutting and welding. Supplied in a 30 litre Integra® cylinder containing 5.8 kg. Integra® cylinders are safer, smaller and lighter. The Integra® cylinder is designed to be used with a choice of Integra® cylinder flash back arrestors (available separately).