Lead-free solder alloys have been around for as long ... These higher silver alloys are true eutectic alloys — completely changing form a solid to a liquid at the melting point of 217°C.

The video does have a bit of theory on soldering chemistry and the difference between eutectic alloys and other tin-lead mixes, as well as a little about the proper use of silver-bearing solders.

The phase diagram between lead and tin shows the eutectic invariant reaction between these two constituents. At the eutectic temperature of 183 C, three phases exist in equilibrium: (Pb) with the ...