Spray coating is a coating method where,in one common technique,a stream of compressed air flows over the nozzle of a spray gun,creating a vacuum (negative pressure).This vacuum draws the paint from a reservoir through a tube and out of the nozzle,atomizing it into a fine mist.This mist is then projected onto the surface of the part to be coated,forming a uniform paint film. In addition to this conventional method, other modern techniques are now widely used, such as : electrostatic spray painting,electrophoretic deposition(E-coating),airless spraying.