Rather than solder I end cables with those plastic/rubberized tips that come on the end of the nail portion of sliders (intended to nail on the bottom of chair legs). Keeps the strands together fine and looks vintage too. My source: Home- Depot or Lowes, small size tips colors usually clear, white, or red. Other than that you could use liquid electrical tape ( brush is affixed to lid- black only) Source: Wallmart- But that is a little messier.
Mark Cutrufelli
Laurel,MD