Sewing Materials - binding materials:

Thread: Sewing is the central operation in binding. The life of binding depends very much on the kind of sewing and the material used for sewing. Thickness of the thread must be appropriate to the thickness of the book. Too thick thread for a thin volume or vice-versa will result in damage to the book or to binding. Thread used should be of superior  quality otherwise, binding may become undone causing wastage. Irrespective of the sewing method, sewing depends on the quality of thread. The varieties of threads include cotton, linen, silk, nylon and terylene. These varieties differ in quality. Linen thread is much stronger and cheaper than cotton. Silk thread is much stronger and cheaper than cotton. Silk thread though used in the past it found to be unsatisfactory as it is difficult to handle. Modern synthetic fibres are  much stronger and uniform. These are free from any tendency to rot in dampness and retain strength upon wetting. Unlike cotton these  fibres maintain a perfectly smooth kno-free surface. In view of these qualities they are considered to be superior to traditional thread. 

Thread gauze: A closely woven cotton mesh is glued to the spine of the book and both of its ends are inverted into the inner side of the covering board. This is thread gauze adds strength to binding. 

Tapes and cords: Tapes and cords for library binding are made from different fibres. Strips of vellum  are  considered superior to tapes made of other fibres as they are durable. However synthetic types -nylon and  terylene are considered superior to vellum because of their longer fibres. Tapes are used for connectingone section with the other sections. For larger books, cords made up of pigskin, vellum catgut are used for ensuring strong and durable bindings. 

Adhesives: Adhesive, though  necessary for  binding also damage the binding. The damage drying is prone to, cracking. The features expected of a good adhesive, after drying is prone to cracking. The features expected of a good adhesive are its ability to wet the surface of the - materials, fluid form, quick setting and the bond strength. 

There are varieties of adhesive available in the market now. They include starch past, industrial pastes, glues and gelatines and other kinds of glues.