A welder uses heat to melt and join metal pieces or repair damaged components, following technical drawings, specifications, and safety protocols. Key responsibilities include preparing metal surfaces, setting up specialized welding equipment like electric arc or MIG/TIG machines, performing various welding and cutting techniques, inspecting welds for quality, maintaining equipment, and ensuring a safe work environment. Welders work in various industries, including manufacturing and construction, and need a strong understanding of different metal types and welding processes.