Of course, the soldered joints at that time were sword-related and decidedly ... spring for contact force and tin-plated copper outer shell for carrying current ... This risk is even greater when soldering a wire directly to a PCB.
The solder then runs onto the wires or circuit and cools, making one ... If you're soldering a wire onto a control board, one pro move is to pre-tin the tip of the wire.
Solder was typically supplied in the form of flux-cored wire, melted with ... laser and robotic iron selective soldering using lead-tin, tin-antimony, ...