This process requires the use of a thin, rubberised mask to protect areas not to be etched. Once masked, an abrasive powder propelled by compressed air is used to etch away at the surface of the workpiece. The relative hardness difference between the job and the abrasive powder determines whether the surface is simply marked or is deeply eroded. The etched surface is an excellent key for paint and thus, once spray painted, and the mask cleaned away text or an image is seen on the job.
The process can produce relatively fine detail and is especially good for hard to hold objects or those with curved or irregular surfaces. The commonly used materials are stainless steel, aluminium, glass, ceramics and acrylic.