Abstract: Apparatus for spraying powdered materials. A spray gun for applying hot powdered thermoplastic materials to a substrate to be coated may be constructed in such a fashion as to have no moving parts. A first fluid amplifier section inspirates the powdered material and cool air from the outside atmosphere. A second fluid amplifier section also inspirates outside air. This air is heated as it is inspirated. A transition section connects the two fluid amplifier sections. The powdered material inspirated by the first fluid amplifier section mixes with the heated air inspirated by the second fluid amplifier section. This causes partial melting of the powdered material so that as it exits from the second fluid amplifier toward the substrate to be coated, the material is in a condition to allow more uniform coating of the substrate.