Fiberglass
Fiberglass fibers are made of glass and so are not
flammable. The fibers made into thick padding have been
used for insulation as in refrigerators, but are being
replaced in newer models by urethane foam.
Fiberglass fibers are combined with polyester resins
to make a strong, lightweight, rigid material, which is
molded into one-piece tubs and shower stalls, having a
smooth layer of plastic on the surface for easy care.
Some is also used for outdoor table tops.