Rat Tail (Rattail, Rat-tail) – is a fat, satiny cord that is perfect for knotting, and comes in a huge selection of glossy, vibrant colors. It is strong, colorfast, UV resistant, and works well for many crafts besides jewelry making. (I can attest to it’s durability – I use a piece of it to hang the thermometer in the pool. Between the sunlight and the occasional chlorine schock – that is pretty harsh testing.)
It is woven from nylon, and when you cut the end, it will fray very rapidly. The fastest way to stop this is to gently fuse the fibers on the ends with a flame from a lighter or candle.
Hold the flame just close enough for the fibers to melt and fuse, you don’t want a big, black burned gob at the end. With a little practice, the fused part will be almost invisible.
When it comes to adding beads, to keep the end in a nice taper, wrap a little painter’s or masking tape over the end and roll it smooth. Once your beads are added – cut the taped end off and fuse.