Crosby Garrett Helmet some point the helmet was repaired using a bronze sheet which was riveted across two splits. Only two other Roman helmets complete with visors have been found in Britain – the Newstead Helmet and Ribchester Helmet. The helmet and visor were cast from an alloy consisting of an average of 82% copper, 10% zinc and 8% tin. This alloy was probably derived from melted-down scrap brass with a low zinc content, with which some tin had been added to improve the quality of the casting. Some of the fragments show traces of a white metal coating, indicating that the visor
Tin-silver-copper (95%+) tin. For example, the common "SAC305" solder is 3.0% silver and 0.5% copper. Cheaper alternatives with less silver are used in some applications, such as SAC105 and SAC0307 (0.3% silver, 0.7% copper), at the expense of a somewhat higher melting point. SAC alloys are the main choice for lead-free surface-mount technology (SMT) assembly in the electronics industry. SMT is a process where components of circuit assemblies are mounted directly onto the surface of a printed circuit board and soldered in place. SMT has largely replaced “through-hole technology” where components are fitted with wire leads into holes in the circuit