Restoration Process

Chicago State University in conjunction with Lewis developed an applications engineering project. Serial numbers and other markings are frequently eliminated from metal objects to prevent tracing ownership of guns, motor vehicles, bicycles, cameras, appliances and jewelry. New restoration process is called cavitation" which occurs when a liquid is subjected to rapid vibration. Metal object is immersed in water and a probe is positioned immediately above it. Ultrasonic energy is applied causing probe to vibrate rapidly and induce cavitation. Resulting vapor bubbles impact metal surface and pit it. Pitting around area where serial number was stamped gradually restores number.

Full article: http://hdl.handle.net/hdl:2060/20070019728