Operates machine to remove dents from metal barrels: Positions barrel on lower die of machine, aligning bunghole under water spout of machine. Turns side dies of machine to align contour of dies with contour of barrel ends. Presses switch that closes side, top, and bottom dies around barrel. Pumps water into barrel, forcing walls of barrel against dies and removing dents. Stops pump and opens dies after specified water pressure has been attained. Examines surfaces of barrel to verify smoothness. Pushes barrel from lower die onto conveyor. May drain de-dented barrels, pressurize barrels with air, and place barrel in water tank to detect leaks.