On Wednesday, July 16, 2014 5:40:03 AM UTC+1, The Natural Philosopher wrote:
On 16/07/14 05:29, F Murtz wrote:



The silver solder that plumbers use for copper pipe is usually only 2%
silver

Plumbers don't use silver solder for copper pipe.
On the other hand refrigeration engineers do commonly braze or hard solder*
copper pipes, so they may sometimes use silver containing alloys.
*delete whichever term you disagree with :-)