I was working on a project wherein I was soldering 2 severed USB charging cables (2 wires per cable), a micro-USB to a standard USB. But when i had linked the wires together with a generous amount of solder, which did adhere to the wires quite easily, the wires did not connect or at least did not have a low enough resistance for enough current to flow. Could this be an issue with the soldering joints, or is it a problem with the wires inside the insulation having disconnected? I did get these wires from a "broken" USB charging cable which i needed to shorten, so I'm really not sure what the problem is.
Delicate cables can not only fail easily but fail in more than one place. Basic continuity should be there or discard them both and use new ones.