choppersrule:: ... The best is a 60/40, lead tin base with rosin core... Diameter is .031 inches..
Rbohn: ...
2. The finished joint should be completely shiny. If it's dull the joint is "cold soldered" and not reliable. If that happens, reheat it to full liquid, then let it cool again.
3. Don't let anything move while the solder is cooling. If the 2 wires move relative to each other at all, the joint will end up cold soldered, most likely.
If you can find/afford 63/37 solder, it solders better than 60/40. The melt range of 60/40 is 361°-374° F (liquifies at 374° F and solidifies at 361° F ... meaning you have to hold things still until the solder solidifies).
The 63/37 solder melts AND solidifies at 361°F ... essentially eutectic ( ... exhibit no plastic range upon melting, and the melting point is lower than that of any other alloy composed of the same constituents in different proportions ...).
This means you do not have to hold your solder setup still waiting for the solder to soldify. 63/37 soldifies the instant you remove the heat source.