Acetylene is a colorless hydrocarbon in gaseous state. Acetylene has smell of garlic. It is mixed with oxygen and is used in oxyacetylene welding. Acetylene generates more light when compared to the normally used illuminating gas. In welding, if acetylene is used with gauge pressure above 15psig, it is explosive. The available tank sizes of acetylene are 10, 40, 75, 100 and 300 cubic feet.