In my experience JB Weld is great for stationary items. The least bit of movement or vibration and it break's. I tried it on a set of flying wires where the joint was in the fuse. It did not last but one flight, on the second the wires were flapping and the JB was in tiny bits in the bottom of the fuse. I have also tried several low carbon wire for flying wires and they stretched, so I would have to say flying wires are under a good amount of stress and flex. A good way to see the flex in flying wire is to use a hacksaw handle to mount a wire to. Don't tension any more than it would be on an airframe. Then get in your vehicle and get up to 60-80mph and hold the hacksaw out the window, I think you will be surprised at how much they dance.
I don't use anything other than 60% silver based solder now. And no regrets, and yes there was a bit of a learning curve but well worth it.