Abstract: A weld root shield device includes an inert gas supply tube having an open end together with a toroidal inert gas supply chamber having orifices therein surrounding the open end of the gas supply tube for replacing air that could be aspirated by inert gas emerging from the open end of the gas supply tube with inert gas emerging from the orifices of the toroidal supply chamber. The shield device is positioned over the weld root being produced by operation of the welding torch, thereby to protect the weld root from oxidation by the atmosphere. The welding torch and the weld root shield device can travel together as an elongated weld is being formed.