Pultruded fiberglass has earned its place as one of the most versatile construction materials in the world. Its low cost and unique blend of advantages enable it to replace traditional materials such as wood, aluminum, and steel.
In fact, fiberglass outperforms many such substances in terms of strength, weight, and other important properties.
Despite its ubiquitous presence in the modern world, however, pultruded fiberglass still remains something of a mystery to many people.
If you would like to get your facts straight on fiberglass and what it can do for you, keep reading.
This article provides clear answers to some of the most frequently asked questions about pultruded fiberglass.
Pultruded fiberglass — hereafter referred to simply as fiberglass — is a unique structural material combining fiber reinforcements and thermosetting resins.
Pultrusion refers to the process by which fiberglass is made. This process involves either drawing the fibers through a specialized resin bath or injecting resin into the fibers.
Once the fiber has been wetted, machines shape it to the specified dimensions and then pull it into a preheated steel die.
The heat cures the resin as it is pulled through the die. In this manner, fiberglass can be pultruded according to virtually any specification or shape, including sheets, rods, poles, angles, bars, and channels.
The only real limitation is that the pultruded fiberglass must have a constant cross-section.
A frequent source of confusion about fiberglass stems from the various naming conventions used.
Aside from "fiberglass" and "pultruded fiberglass," manufacturers may also use any of the following terms:
The good news is that all of these names refer to essentially the same thing: a composite made from two materials: fiber and resin.
The fiber provides reinforcement, while the resin provides the body—technically, the matrix—necessary to give the product its shape.
The key distinction in fiberglass is the production method.
While most fiberglass structural components are manufactured by pultrusion (as discussed above), fiberglass may also be produced by compression molding, resin transfer molding, open-mold sprayup, and casting.
For this reason, pultrusion-based manufacturers often specify their product as pultruded fiberglass to avoid confusion with fiberglass produced by other methods.
Resin is the component most likely to vary across fiberglass types. Historically, three main types of resin have been used in fiberglass pultrusion:
Polyester remains the most widely utilized resin. While it does not excel in any single category, it offers a strong overall blend of properties: relatively low cost, easy to process, quick to cure, and relatively strong.
Vinyl ester is slightly more expensive than polyester but yields a more durable fiberglass.
For the most part, vinyl ester has a molecular structure much like that of polyester. The difference is that vinyl esters contain fewer ester groups.
This gives the fiberglass significantly greater resistance to water and chemical corrosion.
Epoxy-based fiberglass demonstrates even greater durability, strength, and chemical resistance. In addition, epoxy increases the fiberglass's resistance to high temperatures.
That said, epoxy has more complex processing needs and also tends to carry a higher material cost.
Finally, many pultruded fiberglass manufacturers have begun using polyurethane resin in recent years.
While polyurethane presents certain equipment-related challenges, its performance characteristics are second to none.
Polyurethane has been shown to outperform other resins in strength, toughness, and resistance to heat, ultraviolet light, and environmental factors.
Conductivity can refer to two distinct properties: thermal conductivity and electrical conductivity.
Virtually all materials display some degree of thermal conductivity — in other words, allowing heat to move through them. That said, fiberglass has relatively low thermal conductivity, especially compared to metals.
Electrical conductivity is the ability of a material to conduct electric charge. Metals such as steel, copper, and aluminum all exhibit different degrees of electrical conductivity.
Fiberglass, by contrast, is generally classified as a non-conductive material that can also be used as an electrical insulator.
Fiberglass thus has a distinct advantage over metals when strict conductivity requirements must be met.
However, in certain situations, conductivity may be desirable. In such cases, manufacturers can integrate additional composite materials to impart some conductivity to the fiberglass.
For instance, aluminum fibers are introduced alongside glass fibers during pultrusion of fiberglass.
As the modern world increasingly relies on wireless communications technology, traditional building materials must be re-evaluated for their impact on electromagnetic signals.
Common materials such as concrete, steel, and aluminum exhibit significant attenuation of electromagnetic waves.
Any material that is either magnetic or electrically conductive will block or distort a significant portion of the wireless signals it encounters. Fortunately, fiberglass is neither magnetic nor electrically conductive.
As a result, fiberglass is largely transparent to radio waves, cellular frequencies, and other electromagnetic signals.
For this reason, fiberglass has gained significant traction in the telecommunications industry.
In particular, fiberglass has become the material of choice for erecting cell tower screens. Likewise, fiberglass makes a great choice as a protective covering for antennas and other telecommunications equipment.
Pultruded fiberglass offers numerous benefits, making it one of the strongest, most durable, and most cost-effective building materials currently available.
If the idea of structural fiberglass is still new to you, don't worry. Savvy manufacturers know just how to design the custom fiberglass to meet virtually any need.
To learn more about the different types of fiberglass products they can manufacture for you, please do not hesitate to reach out to the industry leaders at Tencom Ltd.