Abstract: A spray apparatus for applying metallic or non-metallic coatings onto workpieces by thermal deposition includes a spray gun for discharging a spray mixture which spray gun is mounted on a riser surrounding the discharge opening of the spray gun and supporting the spray gun at a given distance from the workpiece. The riser is adjustable in length so that the spray gun is supported at a variable distance from the workpiece, and further has a gas admission nozzle mounted thereon for admitting gas under pressure to the interior of said riser. At its remote end adjacent the workpiece, the riser has release passages permitting escape of the gas admitted under pressure to the riser and preventing infiltration of the surrounding fluid.