In the strictest sense, fiberglass is a trademarked product of the Owens Corning company, invented in 1938 and marketed as a home insulation product (Fiberglas). While home insulation remains one of its most common applications, the name itself has become a generic term for any material containing thin fibers of glass formed into a woven layer or used as reinforcement.
The "glass" in fiberglass is the same basic substance used in windows and glassware. Molten glass is extruded through ultra fine openings measured in microns, resulting in thread-like formations which can be woven together to form a rough cloth or patch. Different resins can then be added to this material, allowing it to be formed and pressed into molds. The result is a heat-resistant, lightweight panel ideal for electronic circuit boards or support structures for complex machinery.
Fiberglass mixed with resins can also be used to form the shell of racing cars or other custom designs. Repairs can be made with a commercial product called Bondo, which is essentially a fiberglass tape mixed with a quick-curing resin. When this material is used for car body work, it can be sanded smooth and painted to match the rest of the vehicle. It may not have the inherent tensile strength of steel, but a skilled auto body repairman can often match the section repaired with fiberglass and resin seamlessly with the rest of the car.
On a larger scale, fiberglass can be mixed with other materials to form a thick insulating pad. The pad containing fiberglass is attached with adhesive to an aluminized backing paper. The material is then divided into standard widths which will fit squarely between the vertical studs (exposed support boards)of an unfinished wall. Copious amounts of fiberglass are packed into the space between the exterior wall and the interior wallboard. Once all of the insulating material has been placed, panels of drywall can be put up to finish off the room.
Fiberglass as a building and insulating material is very versatile, but it is not always easy or safe to use. Because the main ingredient is real glass, microscopic bits of glass powder or shards are often formed. Those installing it insulation should always wear gloves, safety glasses and masks. The glass shards and powder can remain on the skin even after several washings. These particles can be very irritating to the lungs and hands and extremely damaging to the eyes. A protective hand cream barrier may help prevent some fiberglass powder buildup.
If you work around the compressed form of fiberglass (i.e. electronic boards), compressed air may be the best way to remove tenacious residue. Avoid touching eyes or other sensitive areas while working with this material in any form. If the powder does enter the eyes, use plenty of clean water or approved eye wash and visit an eye doctor for emergency examination.