Linda Duncan, age 13, of Indianapolis, Ind., for her question:
HOW IS FIBERGLASS MADE?
Manufacturers use reinforced fiberglass plastics to make automobile bodies, boat hulls, building panels, fishing rods and even aircraft parts. The fibers used to strengthen the plastic may be woven or matted together, or they may be individual strands. Fiberglass reinforced plastics are extremely strong and lightweight and can be molded, shaped, twisted or poured.
Fiberglass is glass in the form of fine threads or fibers. Sometimes it is called fibrous glass.
Often the fibers are finer than human hair and may feel and look like silk. The fibers, which are extremely flexible, are stronger than steel and will not burn, stretch, rot or fade.
Fiberglass is made from sand and other raw materials that are also used to make ordinary glass.
Fiberglass strands are made in a number of different ways. In one method, the raw materials are heated and formed into glass marbles.
After being carefully inspected for impurities, the marbles are melted in special electric furnaces that allow the melted glass to run down through tiny holes at the bottom.
A spinning drum catches the fibers of hot glass and winds them on bobbins, much like threads on spools. The drums revolve faster than the glass flows so the tension p••lls the fibers and draws them out into still finer strands.
The drum can pull out two miles of fibers in a minute. Up to 95 miles of fiber can be drawn from one marble that is only five eighths of an inch in diameter.
The glass fibers can be twisted together into yarns and cords or woven into cloth, tape or other kinds of fabrics.
Another way in which fiberglass is made eliminates the use of marbles. It is called the direct melt process.
Bulk fiberglass, which is sometimes called fiberglass wool, also starts with sand and other raw materials in a furnace. The glass flows from tiny holes and then high pressure jets of steam catch them and draw them into fine fibers from eight to 15 inches long. The fibers are gathered on a conveyor belt in the form of a white wool like mass.
In bulk form, fiberglass is used in air filters and for heat and sound insulation.
Ancient Egyptians used coarse glass fibers for decorative purposes.
Then, in 1893, an American glass manufacturer named Edward Libbey made a dress of fiberglass and silk.
Between 1931 and 1939, the Owens Illinois Glass Company, which is now called Owens Illinois, Inc., and the Corning Glass Works developed practical methods of making fiberglass commercially.