[Bruceb]

Polycord is GREAT never wears out and if you join it properly it will stay together forever.
Trick
Cut the cord 5% under length and cut the ends at a long angle. Then. Take a piece of aluminum and clamp it in a vice. Have someone hold a propane torch against one side and press the ends of the cord against the other side until you see it melt a good bit. Remove them from the heat and press them together. Hold them together until the joint cools. You get probably 90 percent of the joint strength in 10 minutes but for best results let them sit overnight before streching.
Bruce