A gas burner is a device to generate a flame to heat up products using a gaseous fuel such as acetylene, natural gas or propane. Some burners have an air inlet to mix the fuel gas with air to make a complete combustion. Acetylene is commonly used in combination with oxygen. It has many applications such as soldering, brazing and welding, the latter using oxygen instead of air for getting a hotter flame which is required for melting steel.