It is so-called because the flame at the end looks like a rose bud. A welding torch can also be used to heat small areas such as rusted nuts and bolts. Injector torch A typical oxy-fuel torch, called an equal-pressure torch, merely mixes the two gases. In an injector torch, high-pressure oxygen comes out of a small nozzle inside the torch head which drags the fuel gas along with it, using the Venturi effect. Fuels Oxy-fuel processes may use a variety of fuel gases (or combustible liquids), the most common being acetylene. Other gases that may be used are propylene, liquified petroleum gas (LPG), propane, natural gas, hydrogen, and MAPP gas. Liquid fuel cutting systems use such fuels as Gasoline (Petrol) Diesel, Kerosene and possibly some aviation fuels. Acetylene Acetylene is the primary fuel for oxy-fuel welding and is the fuel of choice for repair work and general cutting and welding. Acetylene gas is shipped in special cylinders designed to keep the gas dissolved. The cylinders are packed with porous materials (e.g. kapok fibre, diatomaceous earth, or (formerly) asbestos), then filled to around 50% capacity with acetone, as acetylene is soluble in acetone. This method is necessary because above 207 kPa (30 lbf/in²) (absolute pressure) acetylene is unstable and may explode. There is about 1700 kPa (250 psi) pressure in the tank when full. Acetylene when combined with oxygen burns at 3200 °C to 3500 °C (5800 °F to 6300 °F), highest among commonly used gaseous fuels. As a fuel acetylene's primary disadvantage, in comparison to other fuels, is high cost. As acetylene is unstable at a pressure roughly equivalent to 33 feet/10 meters underwater, water-submerged cutting and welding is reserved for hydrogen rather than acetylene. Gasoline Oxy-gasoline, also known as oxy-petrol, torches perform extremely well, Tests showed that an oxy-gasoline torch can cut steel plate up to thick at the same rate as oxy-acetylene. In plate thicknesses greater than the cutting rate was better than that of oxy-acetylene; at it was three times faster. Additionally the liquid fuel vapour is about 4x the density of a gaseous fuel providing much greater "punch". A high velocity cutting flame is produced by the huge volume expansion while the liquid transitions to a vapour so the cutting flame will easily cut across voids (air space between plates). Cuts through paint, dirt, rust and other contaminating surface materials coating old steel. This system