A professional who rebuilds safety and flow valves used on compressed and liquefied gas cylinders, drums, or railway cars. Responsibilities include:

• Disassembles valve, using bench vise and handtools.
• Inspects components for surface flaws, and defects in stem and threads.
• Reams valve seats with hand reamer and dresses threads with tap and die.
• Immerses parts in cleaning solution and reassembles valve.
• Dips valve in molten lead, using tongs, to prevent leakage.
• Attaches valve and fusible plug to high-pressure gasline, submerges it in water, and observes for bubbles to test valve and plug for leaks.
• Melts out defective plugs, scrapes hole clean, and pours in new metal.
• Records number of valves tested and test results.
• May attach gauge and open air valve to test filled cylinders for pressure.
• May brush or spray chemical solution around valves to test filled cylinders for leaks.
• May fill cylinders.