Yetholm-type shield of dots. The artist could not hope to show the fine detail of a Yetholm-type shield, but the similarity is striking. The impressive shields would have indicated high social status. The shields are made of a copper alloy sheet about 0.6 mm thick. The alloy is a high-tin bronze: copper with 11-14% tin. They are round with a central domed boss created by hammering out from the back. The shield face is covered in raised ridges in concentric rings, each a couple of millimetres high. Between the ridges are rings of small hemispherical bosses about 4 mm across. Decoration was
Tin-silver-copper been increasing. Large companies such as Sony and Intel switched from using lead-containing solder to a tin-silver-copper alloy. The process requirements for SAC solders (Pb-free) and Sn-Pb solders are different both materially and logistically for electronic assembly. In addition, the reliability of Sn-Pb solders is well established, while SAC solders are still undergoing study, (though much work has been done to justify the use of SAC solders, such as the iNEMI Lead Free Solder Project). One important difference is that Pb-free soldering requires higher temperatures and increased process control to achieve the same results as that of the tin-lead method.