How is Fiberglass Made?

   Fiber glass is very strong and flexible and is resistant to extreme temperatures, moisture, oils, and caustic chemicals. In combination with plastics, fiber glass is becoming increasingly important as a structural material.
   Fiber glass is made from glass marbles that are melted and poured through tiny boles. As the molten glass drops through the boles, it forms into threads, which are subjected to air or steam pressure. The size of the holes and the amount of pressure determine the thickness of the threads that are formed. These threads can be spun into yarn. Fiber glass yarn can be woven into fabrics that resemble cotton, wool, or silk. Drapes and curtains are among the many textile producís made of fiber glass.
   Another kind of fiber glass, called glass wool, is drawn in short fibers directly from a batch of molten glass. Glass wool is made into blankets or matting that is used for insulation against heat and sound.
   Many materials are made by combining fiber glass with various plastics. These materials, generally also called fiber glass, can be pressed into sheets or molded into various shapes. They are used for acoustical ceilings, roofing shingles, tile, and construction boards in a wide range of texture and flexibility. Thin fiber glass sheets are suitable substitutes for metal in the manu¬facture of storage tanks, air ducts, and similar products.
   Fiber glass composition material has become increasingly important in the construction of automobile bodies and boat hulls. Automobile bodies and some boat hulls of this material are formed by a hydraulic press in a single operation. Most such boat hulls, however, are made by pressing many sheets of fiber glass onto a mold by hand. Fiber glass boat hulls and automobile bodies do not corrode and are easily repaired.