Ceramic Tubed Standard Bobbin Wrapping thread around a hook pulls the thread around and around the inside of the bobbin tube, creating heat and eventually abrading the surface of the tube. This results in thread breaks and nicks in the bobbin tube. Ceramic material is much more resistant to heat than other materials used to create bobbins. Ceramic material is one of the best insulators available, and some of the world's best fly tying bobbins use it as a tube or tube liner.