Fiberglass is an immensely versatile material which combines its light weight with an inherent strength to provide a weather resistant finish, with a variety of surface textures.
The development of fiber reinforced plastic for commercial use was being extensively researched in the 1930s. It was particularly of interest to the aviation industry. Mass production of glass strands was accidentally discovered in 1932 when a researcher at the Owens-Illinois directed a jet of compressed air at a stream of molten glass and produced fibers. Owens joined up with the Corning company in 1935 and the method was adapted by Owens Corning to produce its patented “Fiberglas” (one “s”). A suitable resin for combining the “Fiberglas” with a plastic was developed in 1936 by du Pont. The first ancestor of modern polyester resins is Cyanamid’s of 1942. Peroxide curing systems were used by then.
During World War II it was developed as a replacement for the molded plywood used in aircraft radomes (fiberglass being transparent to microwaves). Its first main civilian application was for building of boats and sports car bodies, where it gained acceptance in the 1950s. Its use has broadened to the automotive and sport equipment sectors as well as aircraft, although its use there is now partly being taken over by carbon fiber which weighs less per given volume and is stronger both by volume and by weight. Fiberglass uses also include hot tubs, pipes for drinking water and sewers, office plant display containers and flat roof systems.
Advanced manufacturing techniques such as pre-pregs and fiber rovings extend the applications and the tensile strength possible with fiber-reinforced plastics.
Fiberglass is also used in the telecommunications industry for shrouding the visual appearance of antennas, due to its RF permeability and low signal attenuation properties. It may also be used to shroud the visual appearance of other equipment where no signal permeability is required, such as equipment cabinets and steelsupport structures, due to the ease with which it can be molded, manufactured and painted to custom designs, to blend in with existing structures or brickwork. Other uses include sheet form made electrical insulators and other structural components commonly found in the power industries.
Because of fiberglass’s light weight and durability, it is often used in protective equipment, such as helmets. Many sports utilize fiberglass protective gear, such as modern goaltender masks and newer baseball catcher’s masks.
Storage tanks: Storage tanks can be made of fiberglass with capacities up to about 300 tonnes. The smaller tanks can be made with chopped strand mat cast over a thermoplastic inner tank which acts as a preform during construction. Much more reliable tanks are made using woven mat or filament wound fibre with the fibre orientation at right angles to the hoop stress imposed in the side wall by the contents. They tend to be used for chemical storage because the plastic liner (often polypropylene) is resistant to a wide range of strong chemicals. Fiberglass tanks are also used forseptic tanks.
House building: Glass reinforced plastics are also used in the house building market for the production of roofing laminate, door surrounds, over-door canopies, window canopies and dormers, chimneys, coping systems, heads with keystones and sills. The use of fiberglass for these applications provides for a much faster installation and due to the reduced weight manual handling issues are reduced. With the advent of high volume manufacturing processes it is possible to construct fiberglass brick effect panels which can be used in the construction of composite housing. These panels can be constructed with the appropriate insulation which reduces heat loss.
Piping: GRP and GRE pipe systems can be used for a variety of applications, above and under the ground.
- Firewater systems
- Cooling water systems
- Drinking water systems
- Waste water systems/Sewage systems
- Gas systems
Fiberglass hand lay-up operation: A release agent, usually in either wax or liquid form, is applied to the chosen mold. This will allow the finished product to be removed cleanly from the mold. Resin – typically a 2-part polyester, vinyl or epoxy – is mixed with its hardener and applied to the surface. Sheets of fibreglass matting are laid into the mold, then more resin mixture is added using a brush or roller. The material must conform to the mold, and air must not be trapped between the fiberglass and the mold. Additional resin is applied and possibly additional sheets of fiberglass. Hand pressure, vacuum or rollers are used to make sure the resin saturates and fully wets all layers, and any air pockets are removed. The work must be done quickly enough to complete the job before the resin starts to cure, unless high temperature resins are used which will not cure until the part is warmed in an oven. In some cases, the work is covered with plastic sheets and vacuum is drawn on the work to remove air bubbles and press the fiberglass to the shape of the mold.
Fiberglass spray lay-up operation: The fiberglass spray lay-up process is similar to the hand lay-up process but the difference comes from the application of the fiber and resin material to the mold. Spray-up is an open-molding composites fabrication process where resin and reinforcements are sprayed onto a mold. The resin and glass may be applied separately or simultaneously “chopped” in a combined stream from a chopper gun. Workers roll out the spray-up to compact the laminate. Wood, foam or other core material may then be added, and a secondary spray-up layer imbeds the core between the laminates. The part is then cured, cooled and removed from the reusable mold.
Pultrusion operation: Pultrusion is a manufacturing method used to make strong light weight composite materials, in this case fiberglass. Fibers (the glass material) are pulled from spools through a device that coats them with a resin. They are then typically heat treated and cut to length. Pultrusions can be made in a variety of shapes or cross-sections such as a W or S cross-section. The word pultrusion describes the method of moving the fibers through the machinery. It is pulled through using either a hand over hand method or a continuous roller method. This is opposed to an extrusion, which would push the material through dies.
Chopped strand mat: Chopped strand mat or CSM is a form of reinforcement used in fiberglass. It consists of glass-fibers laid randomly across each other and held together by a binder.
It is typically processed using the hand lay-up technique, where sheets of material are placed in a mold and brushed with resin. Because the binder dissolves in resin, the material easily conforms to different shapes when wetted out. After the resin cures, the hardened product can be taken from the mold and finished.
Using chopped strand mat gives a fiberglass with isotropic in-plane material properties.