There are two things called 'silver solder', and they are very different. There is a 'brazing' type alloy, melting at round 600 to 700 deg C, depending on its exact formulation, and there is a 'soft solder' of tin, lead and silver (and maybe some other stuff) melting around 180 to 250 deg C, depending on alloy. One needs to be clear about which is meant. 73 Peter G3RZP