No abstract

Chemical reagents for serial number restoraton are designed to exploit the plastc deformaton zone below the obliterated serial number. Most techniques in operatonal use are variants of Fry's Reagent. This technique uses toxic, corrosive chemicals and requires a skilful operator in the laboratory. Fry's Reagent can also be destructve of the frearm due to rustng. In an atempt to fnd a non-ttoxic, non-tdestructve alternatve to Fry's Reagent, this project tested the use of liquid dye penetrants (LDPs), a non-tdestructve examinaton technique to detect cracks and imperfectons used in the welding industry, for the restoraton of obliterated serial numbers. Steel plates bearing an obliterated serial number with a range of obliteraton depths were subjected to LDP treatment under various treatment conditons.The results using LDPs were negatve for all obliteraton depths and all test conditons atempted. Some of the serial numbers were subsequently restored successfully with Fry's reagent, proving that the plastc deformaton zone was present on the steel plates below the obliteraton. Further work to develop a non-ttoxic, non-tdestructve serial number restoraton process will be undertaken.

No abstract