An apparatus and a method for automatically welding a T-junction connector to a main pipe are disclosed. The apparatus includes a rotatable frame which is provided with a movable bracket for supporting a welding gun. The frame is preferably attached by a vertical shaft to a portable framework having a wheeled leg and a pair of spaced apart horizontal handles. The portable framework may be moved from one location to another on its wheeled leg. The frame is rotated about the shaft by a computer controlled motor. Two other motors mounted to the frame are interconnected with the bracket for supporting a welding gun or torch, and adapted to move the welding gun along axes parallel with and normal to a T-junction connector supported in a preformed hole in a main pipe.