Welding is the most common way of permanently joining metal parts. In this process, heat is applied to metal pieces, melting and fusing them to form a permanent bond. The work that welders do and the equipment they use vary, depending on the industry. Welders may work outdoors, often in inclement weather, or indoors, sometimes in a confined area designed to contain sparks and glare. Most welders work full-time and overtime hours are common.