This student guide, one of a series of correspondence training courses designed to improve the job performance of members of the Marine Corps, deals with the skills needed by metal workers and welders. Addressed in the six individual units of the course are the following topics: weldable metals and their alloys, arc welding, gas welding, metalworking machines and tools, repair of equipment and interpretation of welding symbols, and welding symbols. Each unit contains a general objective, a series of work units addressing different subobjectives, study questions, and answers to the study questions. (MN)