Four years of welding experience; or, Completion of an accredited four-year welder's training program; or, Completion of an accredited two-year welder's training program and two years of welding experience; or, any equivalent combination of experience and/or education from which comparable knowledge, skills and abilities have been achieved. Designs, fabricates, joins and/or repairs space age metals, scientific and research components using oxygen-acetylene, electric arc, MIG and TIG welding techniques.