What is Pultrusion?

Pultrusion is a manufacturing process for converting reinforced fibers and liquid resin into a fiber-reinforced plastic, also known as fiber-reinforced polymer (FRP).

The pultrusion process allows continuous production of FRP structural shapes in an automated, energy-efficient process by pulling fiberglass rovings through a resin bath or resin impregnator that completely saturates the reinforcements. The resin hardens from the heated steel pultrusion die, resulting in a strong, lightweight final product that follows the shape of the die.

The rovings of fiber reinforcements are positioned by the creels for continuous feeding onto the guide plate. To ensure strength and quality, the fiber reinforcements must be positioned accurately within the finished composite.

The fibres are usually glass (in fibreglass), carbon (in carbon-fibre-reinforced polymer), aramid, or basalt.

The most popular liquid resins or polymers are epoxy, vinyl ester, polyurethane or polyester thermosetting plastic, though phenol formaldehyde resins are still in use. 

Pressure Vessel Engineering Designed to AS1210

Glass Fibers:

Glass fibers can be made from various types of glass, depending on their intended application.

E glass – It is an excellent electrical insulator, also known as electrical glass. This is one of the most commonly used Fiberglass in the industry.

S glass – Also known as structural glass. S-glass is used for its mechanical properties.

C glass – Also known as chemical glass. C-glass offers great resistance to chemical impact.

A glass – Also known as alkali glass. This also offers resistance to chemicals. It is used to make process equipment in some countries.

AE glass – Alkali-resistant glass.

Mechanical Properties and Description of Different Glass Fiber Types

Pressure Vessel Engineering Designed to AS1210

Polymers (Liquid resins):

Following are the most used resins in the industry.


Polyester resin is the most used resin. It has excellent mechanical and chemical stability, as well as low cost and easy to use. It has a wide range of applications. Their main applications are in the construction industry, automotive industry, and boat building, boat repair, industrial application like machine repair, domestic and roofing applications.


Epoxy Resin is highly adhesive and durable resin and is used in a wide range of normally very high specification products from aircraft components, boat building, industrial and commercial flooring markets and the construction industry. Epoxy resin, when used with carbon fibre to create incredibly strong, rigid and lightweight structures. Compared to polyester resin is more expensive, but possesses greater strength and therefore has more direct applications.


It is a common resin in the marine industry due to its corrosion resistance and ability to withstand water absorption. Vinyl ester resin is extensively used to manufacture FRP tanks and vessels as per BS4994. It has greater strength and mechanical properties than polyester and less than epoxy resin.

Mechanical Properties of Different Resin Types

The specific physical properties will vary depending on the formulation.

Resin Type

Density (g cm−3)

Tensile Strength (Mpa)

Young’s Modulus (Mpa)









Vinyl Ester 




Applications of Pultruded Fiberglass:

Fiberglass is extremely strong, lightweight, and flexible. Fiberglass can be moulded into many complex shapes depending on different customer requirements.

This explains why fiberglass is widely used in the

  1. Aerospace industry, and Automotive industry for the production of structural and complex parts of the vehicles with enhanced stiffness, rigidity and lightness;
  2. Sports and tourism industries for manufacturing of equipment
  3. Construction industry for the production of profiles, carcasses, stiffening bars for PVC-windows, etc.;
  4. Agriculture and chemical industries
  5. Electrical power engineering for manufacturing of dielectric structures
  6. Marine Industry to prevent salty seawater from causing damage, such as rust and corrosion.
  7. And in many other industries and plants, mechanisms, structures, and materials meet high chemical, dielectric, and strength stability standards.

Our Products:

We pultrude all types of open & closed sections in different shapes & sizes and colors as per the design & needs of our customers. We pultrude profiles such as round tubes, box sections, Angles, Channels, I Beams, U Sections, solid rods & some complex shapes as well. For producing customized shapes, 1st procedure is to make the die and then the profile. It is like a one-time investment.

Talk to Us

CSA Engineering, as we are in the aerospace, rail, automotive and industrial design industries, we work with designers, builders, and manufacturers to realize a wide range of design possibilities. We specialize in providing cost-effective engineering and design services. Our team of experienced specialist engineers is dedicated to helping you customize and implement your design in the manufacturing process. Our products are high in demand due to their premium quality, seamless finish, different patterns and affordable prices. Furthermore, we ensure to deliver these products to our clients timely; through this, we have gained a huge client base in the market.

Contact us today. We’d be delighted to talk you through the options.

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