Spray painting is a painting technique where a device sprays a coating (paint, ink, varnish, etc.) through the air onto a surface. The most common types employ compressed gas—usually air—to atomize and direct the paint particles. Spray guns evolved from airbrushes, and the two are usually distinguished by their size and the size of the spray pattern they produce. Airbrushes are hand-held and used instead of a brush for detailed work such as photo retouching, painting nails or fine art. Air gun spraying uses equipment that is generally larger. It is typically used for covering large surfaces with an even coating of liquid. Spray guns can be either automated or hand-held and have interchangeable heads to allow for different spray patterns. Single color aerosol paint cans are portable and easy to store.
Shotblasting is a method used to clean, strengthen (peen) or polish metal. Shot blasting is used in almost every industry that uses metal, including aerospace, automotive, construction, foundry, shipbuilding, rail, and many others. Airblast machines can take the form of a blast cabinet, the blast media is pneumatically accelerated by compressed air and projected by nozzles onto the component. For special applications a media-water mix can be used, this is called wet blasting.
In both air and wet blasting the blast nozzles can be installed in fixed positions or can be operated manually or by automatic nozzle manipulators or robots. The blasting task determines the choice of the abrasive media, in most cases any type of dry or free running abrasive media can be used.