For most of the history of industrial electronics, solder has been pretty boring. Mix some lead with a little tin ... marked the end of the 60:40 alloy’s reign as the king of electrical ...

you want 60/40 (60% tin, 40% lead). Most modern electronics are lead free, but for hobby work lead is fine. Just wash your hands when you’re done! The solder produced for plumbing work is ...

Alloys are specified as a chemical "formula" of sorts, with the percentage of each element represented as a subscript. For example, a tin/lead solder containing 63% tin and 37% lead is referred to as ...