The main fabrication trades are those of plater and welder. A person who is involved in both of these trades is called a fabricator. Plating and welding is known as Heavy Fabrication. A plater will produce work made from thick metal plate and structural steel sections. The metal has to be cut by using a very powerful guillotine or oxy-fuel gas cutting equipment. If the at metal plate has to be curved or round, it is formed and rolled to shape which takes great skill. By using other equipment such as powered rollers and folding machines, very complicated and large shapes can be produced. When the various shapes have been produced they are joined together to complete the fabrication.The various parts or units are joined together using one of the welding processes. This may be done by the same person, usually known as a fabricator or by someone who is a specialist, a welder, whose sole job is to weld parts together.
The process of welding is that of joining together metal to ensure that the parts joined are of equal strength to the parent metal. The type of metal to be joined and the position it is in will determine the level of skill necessary to weld the metal together. There are various welding processes such as Manual Metal Arc (M.M.A.) Tungsten Arc Gas Shielded (T.I.G.) and Metal Inert Gas Shielded (M.I.G.). Platers, welders and fabricators often produce very large items weighing many tons, such as oil rigs, storage tanks, bridges and the structural framework for buildings.