THREAD ZAP II
I just love this tool. You could melt the ends of your nylon string or cord with a match or a lighter but you run the risk of actually burning the cord not melting it. This tool heats up very quickly! You use the tip to make a nice melted ball/button/tab at the end of your cord. You could use it to "zap" silk and cotton cords but I think it is pointless since you can't melt those kinds of cords. It uses one AA battery. I suggest using rechargeable batteries.