Glass-reinforced plastic
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The composite Rutan VariEze, a home-build light aircraft |
Glass-reinforced plastic (
GRP), is a
composite material or
fibre-reinforced plastic made of a
plastic reinforced by fine
fibers made of
glass. Like
graphite-reinforced plastic, the composite material is commonly referred to by the name of its reinforcing fibers (
fiberglass), an example of part-for-whole
metonymy. The plastic is most often
polyester or
vinylester, but other plastics, like
epoxy (GRE), are also sometimes used. The glass is mostly in the form of chopped strand mat (CSM), but woven fabrics are also used.
GRP/GRE is a versatile material with many uses. Although GRP was originally developed in the
UK during the
Second World War as a replacement for the molded plywood used in aircraft
radomes (GRP being
transparent to
microwaves) its first main civilian application was for building of
boats, where it gained acceptance in the
1950s, and now plays a dominant role. But its use has broadened over the years, and it is used extensively within the automotive and sport equipment sectors, although its use there is being taken over by
carbon fiber because of its lower weight. GRE is also used to make
hot tubs, pipes for drinking water, sewers, chemicals, and so on.
Advanced manufacturing techniques such as pre-pregs and fibre rovings extend the applications and the tensile strength possible with fibre-reinforced plastics.
GRP is also widely 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
steel support structures, due to the ease with which it can be moulded, manufactured, and painted to custom designs, to blend in with existing structures or brickwork.
GRP is also manufactured in sheet form and used for manufacturing electrical insulators and other structural components commonly found in the power industries. GRP materials for these uses are marketed under the trade name
Glastic, or referred to generically as
GPO materials like
GPO-3. Parts manufactured from these materials are generally machined instead of formed to guarantee dielectric consistency from part to part.
Chopped strand mat or
CSM is a form of reinforcement used in glass-reinforced plastic. It consists of
glass-fibres 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 glass-reinforced plastic with
isotropic in-plane material properties.
*
Thorpe Park's 'Tidal Wave' ride uses reinforced GRP for its 4 tonne boats.
*
Sailplanes have been built almost exclusively of reinforced plastic since the mid-1960s, with carbon, aramid and other fibres taking the place of glass in modern competition sailplanes, and with extensive use of high strength rovings.
*The hollow
rotor blades of large
wind turbines are usually made of GRP.
*Kayaks are often made of chopped strand mat and polyvinylester because they are strong, durable, and are easily shaped.
*
Gelcoat*
Fiberglass molding*
Building a fibreglass fishing boat*
The resin families*
GPO Material Data Sheet
