Apparently non-lead-free plumbing solder is usually 50/50 tin-lead. I wonder why that is, when it's so far from eutectic? Electrical solder is almost always either 60/40 (a simple ratio close to eutectic) or 63/37 (exactly eutectic).
@JulieSqveakaroo But eutectic alloys are, almost by definition, easy to make. They have the lowest melting point of any possible combination of the metals, and they have a single melting point rather than a melting range.
Huh... I don't know, then...
@JulieSqveakaroo Cost to make could be it though. Tin is more expensive than lead, so using an equal mixture instead of a tin-rich 60/40 would be cheaper.
Sadly, that is possible... a lot of the metals we get in at the shop are less than ideal due to a higher qvantity (though still in the standard ranges) of the cheaper metals in the smelt.
@Felthry
Likely cost to make or difficulty to smelt.