Welders join metal pieces by use of electric arc equipment. Because of its strength, welding is used to construct and repair parts of buildings, machinery, tools, ships, automobiles, spacecraft and thousands of other products. Welders are highly skilled technicians who must be familiar with the properties of metal, blueprint reading, safety procedures, various welding procedures, and processes as well as the operation of hand-held equipment, and a variety of welding machines. Before being assigned to work on buildings, bridges, pipelines or other jobs where the strength of the weld is highly critical, welders may be required to pass a certification examination of their welding skills. Aptitudes and Interests: Welders should have an interest in the construction trades and be willing to wear protective clothing, safety shoes, goggles, helmets and other devices to prevent burns and eye injuries. Welders must have very good manual dexterity, eye-hand coordination as well as good form and spatial perception.