Glass fiber is a mass of very fine strands of glass. When ordinary glass is spun into thin threads it is strong and bendable, unlike normal glass objects, which are brittle and break easily. These silky strands of glass can be woven into a material or massed together like cotton wool. Glass fiber does not decay or corrode. It is a good insulator and a poor conductor of electricity. Curtains made of this material do not rot in damp conditions or in sunlight. Now that technical dyeing problems have been overcame, glass fiber can be patterned.
Many plastics tend to crack or bend under stress or impact, but combining them with strands of glass fiber results in very light, strong and useful materials. Glass fiber increases their strength in much the same way as concrete is reinforced with steel rods. These mixtures are moulded to make such things as aircraft parts, car bodies, boats and fishing rods. Coarse mats of glass fiber are used for filters and washers, and blankets of the material provide good insulation for houses.