Abstract: A narrow beam arc spray head device includes a convergent-divergent nozzle; a number of wires the paths of which intersect at a point in the nozzle; controller for supplying an electrical current to the wires so that an arc is formed between the wires causing a portion of at least one of the wires to melt; a primary axial gas stream impinging upon the wire path intersection to cause the molten metal to be carried axially away from the area of the intersection; and a secondary gas stream forming a generally conical sheath around the axial gas stream in the divergent portion of the nozzle; whereby the primary gas stream and the secondary gas stream emerge from the nozzle as substantially coaxial gas streams thus tending to concentrate the flow of the molten metal carried by the coaxial streams. The spray head device may also include a regulator for regulating the secondary gas stream relative to the primary axial gas stream.