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15 Different Types of Fiberglass

Photo collage of different types of fiberglass.

Fiberglass or glass fiber is one of the most predominant fibers that are used in the industry of reinforced polymer. Other than fiberglass, carbon fiber, and Kevlar are reinforcements that are commonly used. Fiberglass is highly versatile and can be made into sheets or randomly woven into fabrics.

The glass fibers can be made into different types of glass, depending upon the purpose for which it is to be used.

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Background of Fiberglass

Glass fiber was invented by Rene Ferchault de Reaumur. Large scale production of glass fiber started at the end of the eighteenth century. Until 1935, it remained a neglected composite material, and it was only after fiberglass was made into yarn that it gained popularity. 

Fiberglass was first used in the aviation industry as a composite material. Since then, it has been used in numerous commercial applications. Fiberglass has been so named because it is made from glass – the same glass that is used to make windows and kitchen glasses.

However, it is the manufacturing method that gives it the form that you know of. The glass is melted and forced through holes that are superfine in diameter. The filaments of glass that are produced are extremely thin and can be woven into sheets or made into puffy substances that are used in soundproofing and insulation.

Today, glass-reinforced fiber or fiberglass is used in the manufacturing of a number of products, ranging from automobiles to aircraft to hot tubs and shower enclosures. Fiberglass is more flexible and less expensive than carbon fiber. It also has the distinction of being stronger than many metals.

It is lightweight and highly malleable, which means that it can be molded into different shapes with ease. Fiberglass has completely taken over the market for all the right reasons. If you want to know what exactly fiberglass is and why is it dominating the industry, you may want to read further to learn all there is know about fiberglass.

Properties of Fiberglass

Fiberglass fabric composite roll material

Fiberglass is the most popular reinforcement polymer due to its array of properties. As we said earlier, fiberglass is making the rounds in many different industries for all the right reasons. Let’s have a look at its properties.

Mechanical Strength

The specific resistance of fiberglass is greater than that of steel, which makes it high-performance reinforcement material.

Electrical Characteristics

Fiberglass has good electrical insulation even when its thickness is incredibly less.

Dimensional Stability

One of the best properties of fiberglass is that it is not sensitive to variations in hygrometry or temperature. The coefficient of linear expansion is fairly low.

Thermal Conductivity

The thermal conductivity of fiberglass is low, which makes it a very useful material in the construction industry.


Another feature that makes fiberglass a popular material to be used is its mineral composition. As it is a mineral material, it is incombustible, which means that it does not support or propagate flame. It does not emit toxic substances or smoke even upon exposure to heat.

Compatibility with Organic Materials

Fiberglass is available in different sizes. It has an ability to combine with a number of mineral matrices, such as cement, and also with numerous synthetic resins.


Fiberglass is a very durable material as it does not rot. It is not affected by insects or rodents. This ensures the structural integrity and the longevity of structures that are built using fiberglass.

Dielectric Permeability

Fiberglass is dielectric permeable, as a result of which, it can be used in the making of electromagnetic windows.

Basic Composition of Fiberglass

Fiberglass can be made into many types to suit specific uses. Different types of fiberglass have varying compositions that result in a distinct characteristic of each type of fiberglass. The basic composition of all types of fiberglass is the same with the exception of a few raw materials.

The quantities of all raw materials in each type of fiberglass are different, hence giving each type a unique set of properties. The basic raw materials that are used in the manufacturing of fiberglass include silica sand, soda ash, and limestone. Other ingredients include borax, calcined alumina, magnesite, kaolin clay, feldspar, etc.

Silica sand is the glass former and soda ash and limestone lower the melting point. Other ingredients contribute to the improvement of different properties. For example, borax improves chemical resistance.

Types of Fiberglass Based on Their Properties

Fiberglass composite material roll

As discussed above, there are many types of fiberglass depending upon the composition. The major types of fiberglass have been listed below:

1. A-Glass Fiber

A-glass is also known as alkali glass or soda-lime glass. It is the most commonly available type of fiberglass. About 90% of the glass that is manufactured is alkali glass. It is the most prevalent type that is used in making glass containers like jars and bottles for food and beverages, and windowpanes. Sometimes, the bakeware that you use is made from tempered soda-lime glass.

Soda-lime glass is chemically stable, relatively inexpensive, extremely workable, and quite hard. It can be re-melted and re-softened numerous times, which is why A-glass type fiberglass is the ideal type of glass for glass recycling.

Raw Materials Used for Making A-Glass Fiber

The core materials that are used to make a-glass include:

  • Soda (sodium carbonate)
  • Lime
  • Silica (silicon dioxide)
  • Dolomite
  • Alumina (aluminum oxide)
  • Fining agents like sodium chloride and sodium sulfate

Manufacturing of Soda Lime Glass

All the raw materials are melted in a glass furnace at a temperature of 1675 degree Celsius. Inexpensive chemicals like sand, trona, and feldspar are used instead of pure chemicals. The mix of raw materials in the glass furnace is called the batch.

Types of Soda Lime Glass

Soda-lime glass is technically divided into two types, which are: flat glass and container glass. Flat glass is the glass that is used to make windows, and container glass is the type of glass that is used to make containers. Flat glass and container glass not only differ in application but also in the method of manufacturing and the chemical composition.

Flat glass is prepared using the float process while container glass is manufactured by blowing and pressing. As for the difference in the chemical composition, flat glass has a higher quantity of magnesium oxide and sodium oxide and a lower quantity of silica, aluminum oxide, and calcium oxide as compared to container glass. Container glass has a low content of highly water-soluble ions like magnesium and sodium, which makes it more chemically durable for the storage of food and beverages.

2. C-Glass Fiber

C-glass or chemical glass shows the highest resistance to chemical impact. It provides structural equilibrium in corrosive environments. This property is due to the presence of high quantities of calcium borosilicate.

The pH value of the chemicals that are used in the manufacturing of A-glass type fiberglass provides fairly high resistance to this type of fiberglass, regardless of the environment (acidic or alkaline). C-glass is used in the outer layer of laminates in the form of surface tissue for pipes and tanks that hold water and chemicals.

3. D-Glass Fiber

D-glass is a type of fiberglass that is known for its low dielectric constant, which is due to the presence of boron trioxide in its composition. Due to this characteristic, D-glass is the ideal type of fiberglass to be used in optical cables. D-glass also contains borosilicate, which gives this type of fiberglass an extremely low coefficient of thermal expansion.

Due to these properties, D-glass is often used in electrical appliances and cookware.

4. E-Glass Fiber

E-glass is more commonly known as electrical glass. It is a lightweight composite material that is used in aerospace, marine, and industrial applications. E-glass fiberglass cloth is an industry-standard that provides a balance between performance and cost.

Its draping characteristic is excellent and makes it cleaner to work with.

Raw Materials Used to Make E-Glass Fiber

E-glass is an alkali glass. The raw materials that are used in the manufacturing of E-glass fiberglass are:

  • Silica (silicon dioxide)
  • Alumina (aluminum oxide)
  • Calcium oxide
  • Magnesium oxide
  • Boron trioxide
  • Sodium oxide
  • Potassium oxide

Properties of E-Glass Fiber

The key properties that make E-glass a popular type of fiberglass are:

  • Low cost
  • High strength
  • Low density
  • High stiffness
  • Resistance to heat
  • Nonflammable
  • Good resistance to chemicals
  • Relatively insensitive to moisture
  • Good electrical insulation
  • Ability to maintain strength in different conditions

Applications of E-Glass Fiber

E-glass was developed to be used in electrical applications, but it is used in numerous other areas as well. It has led to the production of glass-reinforced plastic combined with thermosetting resins. Sheets and panels made from glass reinforced plastic are used quite extensively in nearly all industrial areas.

It protects the structural integrity against any mechanical impact.Randomly arranged fiberglass filaments

5. Advantex Glass Fiber

Advantex glass fiber is a new industry standard that combines the mechanical and electrical properties of E-glass with the acid corrosion resistance of the ECR type fiberglass. This type of fiberglass meets the standards of acid corrosion resistance of ECR glass at a cost that is similar to E-glass. Advantex fiberglass can be used in applications where thermal fluctuation is greater due to its higher melting point.

Advantex fiberglass contains calcium oxide in high quantities, similar to that of ECR glass fiber. It is used in applications where structures are more prone to corrosion. Moreover, this type of fiberglass is commonly used in the oil, gas, and mining industries, power plants, and marine applications (sewage systems and wastewater systems).

6. ECR Glass Fiber

ECR glass fiber is also called electronic glass fiber. It has high mechanical strength, good waterproofing, and alkali and acid corrosion resistance. It comes with properties that are better than those of E-glass.

The biggest advantage that ECR glass has over other types of fiberglass is that its method of manufacture is environmentally friendly. ECR glass fiber has higher heat resistance, better mechanical properties, lower electrical leakage, better waterproofing, and higher surface resistance as compared to E-glass. ECR glass fiber is used in the making of transparent GRP panels. 

It is made of calcium aluminosilicates that provide its strength, acid corrosion resistance, and electrical conductivity, making it suitable for applications where these properties are needed. The service life of ECR glass is longer. It is a more durable type of fiberglass due to its superior resistance to water, acid, and alkali.

Moreover, it offers higher performance at a lower cost.

7. AR-Glass Fiber

AR-glass or alkali-resistant glass has been developed specifically to be used in concrete. Its composition has been formulated specifically with Zirconia at an optimum level. The addition of Zirconia is what makes this type of fiberglass suitable to be used in concrete.

AR-glass prevents the cracking of concrete by providing strength and flexibility. It is difficult to dissolve AR-glass in water, and it is not affected by changes in pH. Also, it can be added to concrete and steel mixtures with ease.

AR-glass fiber is used in Premix GFRC and other concrete and mortar reinforcement applications. It has a high modulus and tensile strength. Moreover, unlike steel, it does not rust.

The incorporation of AR-glass in concrete mixes is quite easy.

8. R-Glass, S-Glass, or T-Glass Fiber

R-Glass, S-Glass, and T-glass are trade names for the same type of fiberglass. They have greater tensile strength and modulus as compared to E-glass fiberglass. The wetting properties and acidic strength of this type of fiberglass are also higher.

These properties are obtained by reducing the filament diameter. This type of glass fiber is developed for defense and aerospace industries. It is also used in the applications of rigid ballistic armor.

The production volume of this type of fiberglass is lower, which means that its cost is relatively higher. The production volume is low because this type of fiberglass is high-performance and is used only in specific industries.

9. S2-Glass Fiber

S2-glass fiber is the highest-performing type of fiberglass that is available. S2-glass has a higher level of silica in its composition as compared to other types of fiberglass. As a result, it has enhanced properties, better weight performance, high-temperature resistance, high compressive strength, and improved impact resistance.

Above all, S2-glass also offers better cost performance. The tensile strength of S2-glass is approximately 85% more than the conventional fiberglass. It gives consistent high performance and durability.

It has better fiber toughness and modulus of resistance that provides improved impact capabilities to the finished parts, along with a higher damage tolerance, and composite durability. It offers about 25% more linear elastic stiffness and shows excellent tolerance to damage. S2-glass fiber is mostly used in the composite and textile industry due to the physical properties that are better than the conventional types of fiberglass.

10. M-Glass Fiber

M-glass fiber has beryllium in its composition. This element adds additional elasticity to the fiberglass.

11. Z-Glass Fiber

Z-glass is used in numerous industries, including the concrete reinforcement industry, in which it is used for the creation of products that look transparent. It is also used to create 3D printer fibers. With high mechanical, UV, acid, alkali, salt, scratch, wear, and temperature resistance, Z-glass fiber is one of the most durable and reliable types of fiberglass.

Types of Fiberglass Based on Form

Fiberglass is available in the following forms:

  • Tow
  • Veil mats
  • Woven fabrics
  • Chopped strand mat

1. Tow and Roving

When fiberglass is in the form of tow or roving, it exhibits the highest number of properties that are achievable. Fiberglass in this form is supplied on spools that can be unrolled and cut as needed or fed into filament winders. The fibers of the fiberglass must remain in tension to retain their mechanical properties.

2. Veil Mats

Fiberglass, in the form of veil mats, has continuous strands of fibers that have been arranged in thin piles, looped randomly. Veil mats have a consistency similar to that of a tissue paper. They are not intended for any structural applications.

However, they have some very important uses. They can be placed in the mold that is placed directly behind the surface coat to minimize the print through of heavier reinforcing cloths. Moreover, this outer layer – that is quite thin – also allows surface sanding of the finished parts without cutting into the reinforcing fabric that lies below.

The second very important use that veil mats have is that they are used with sandwich cores. They are placed over the core directly in order to maintain the ideal (maximum) bond-line thickness. Veil mats can also keep the excess resin from falling into the cells of honeycomb cores in case a vacuum is not used.

3. Woven fabricsWoven roll of fiberglass fabric

Woven fabrics are fairly strong reinforcements. The fibers in woven fabrics are oriented in two directions and are bundled into yarns. The resulting fabrics are, therefore, stronger.

4. Chopped Strand Mat

Fiberglass Chopped Strand Mat

The length of fibers in this form of fiberglass is 3 to 4 inches. Unlike woven fabrics, the fibers in chopped strand mats are arranged randomly, without any fixed orientation. Fiberglass in this form is not very strong because the length of fibers is quite short. However, fiberglass that comes in this form is the least expensive, and that is why it is also the most commonly used.

Due to the random orientation of fibers, the print through of gels coats is effectively hidden.

The Manufacturing Process of Fiberglass

After all the raw materials are melted into a ‘bulk’ and passed through spinnerets, fiberglass filaments are produced. The filaments are of two types; Continuous filaments and staple filaments.

Continuous Filament Process

Tow continuous filament before dryer

Fiberglass filaments of indefinite length are produced through the continuous filaments process. The spinnerets through which molten fiberglass is passed have numerous (hundreds) small openings. The strands of fiberglass produced are carried to the winder that revolves at a very high speed.

At the end of the process, a yarn of continuous fiberglass filaments is obtained that is used in making drapes and curtains.

Staple Fiber Process

Glass fibers produced through the staple fiber process are long. As the molten bulk passes through small openings, a jet of compressed air converts the streams of molten bulk into long, thin fibers. These fibers form a web that gathers into a sliver.

From the sliver, yarn of fiberglass is made that is then used for insulation purposes in industries.

Applications of FiberglassA swimming pool made of fiberglass

As mentioned several times earlier, fiberglass is one of the most commonly used materials in industrial gaskets. Looking at the properties of fiberglass, we can tell why fiberglass is a preferred material. Its thermal and electrical insulation, strength, and durability are only a few of the many reasons.

Some of the most prominent applications of fiberglass have been listed below:

Aircraft and Aerospace Industry

The material used in the aircraft and aerospace industry has to be stable and lightweight. As compared to E-glass, S-glass has higher strength and modulus, which makes S-glass a preferred type of fiberglass in this industry. Moreover, S-glass also has a higher laminate strength-to-weight ratio, high fatigue life, and high retention at higher temperatures.

It is often used to make helicopter armor, flight deck armor, floors, and seats of aircraft. Because S-glass not only has greater mechanical strength but is also non-conductive, offering lower radar thermal profiles, it allows the military to see without being seen. It is also used to make composite blades for helicopters.

Construction Industry

Fiberglass offers dimensional stability, which makes it an ideal material to be used in construction. Reduced weight, low flammability, impact resistance, and high strength are all the properties that any construction material should have, and fiberglass is everything that it needs to be. Fiberglass is used in the construction of both interior and exterior components of commercial, residential, and industrial constructions, ranging from bathroom fixtures to swimming pool fences to skylights of industrial buildings to solar heating elements.

Consumer Goods

Fiberglass can be seen widely in numerous consumer goods. It is used in the making of furniture frames and finished goods like utility and decorative trays, divider screens, wall plaques, sports equipment, swimming pool and playground equipment, and many more. It is due to its increased flexibility, light-weightiness, higher strength, durability, easy formability, excellent surface, and resistance to wear and corrosion that it is used as a primary material in consumer goods.

Corrosion Resistant EquipmentTanks made up of corrosion-resistant fiberglass

There are a lot of items that have to be made with material that is resistant to corrosion. These are the items that are to be used in hostile environments, and hence, have to be resistant to corrosion so that they can last a long time. The items that have to be made with corrosion-resistant material include drainage and water pipes, underground petrol tanks, cooling towers, sewage systems, flood control structures such as dam gates, and structures involved in the energy production industry.

Since fiberglass is highly resistant to corrosion and wear, it is the ideal material to be used in the making of corrosion-resistant equipment.

Electrical Applications

Temperature stability and mechanical strength are the properties that make fiberglass a suitable material to be used in electronics. It is one of the most common materials that are used to insulate the electrical equipment in industries and for insulation in electronics. Fiberglass coatings are done on wiring to insulate them.

Fiberglass is also used in switchgear, transformers, distribution-pole hardware, computer parts, etc.

Marine IndustryPointed fiberglass hulls of speedboats

70% of boats are constructed with fiberglass. The durability and the strength of fiberglass are the major reasons why it is the dominating material in the marine industry. One of the major pros of using fiberglass in the marine industry is that it can be molded into different shapes easily.

This makes fiberglass extremely easy to work with.

Automobile Industry

The light-weightiness of fiberglass has made it a preferred construction material in the automobile industry. Numerous structural elements of a vehicle are made with fiberglass, such as the belt in a belted-bias tire. Fiberglass is also used to make railway fishplates.

Fiberglass composite has taken over the market like a flood. It has replaced conventional building materials like metal. With continuous improvements and further developments, fiberglass will continue to improve in quality.

It has successfully satisfied the needs of the engineering field to a certain extent, and it continues to further satisfy the requirements of various industries.