Filament Wound vs. Convolute Wound Glass Epoxy: Which is Right for Your Application?

Home > Filament Wound vs. Convolute Wound Glass Epoxy: Which is Right for Your Application?

Published on June 17, 2025

Last updated on July 18th, 2025 at 12:06 pm

Various types of industrial components utilize glass epoxy. Tubing or piping are two elements typically made with this thermoset-based composite, the fabrication for which primarily uses one of two types of construction techniques. Epoxy glass tubing is generally fabricated via either filament winding or convolute winding. When comparing filament wound glass epoxy vs. convolute wound glass epoxy, each method has unique advantages over the other, as well as disadvantages. Choosing the best method for making glass epoxy tubing entails understanding the differences between both these construction methods and their material properties, which affects the applications for which each are used.

Choosing the Best Glass Epoxy Tubing 

Made from composite material, epoxy glass tubing combines reinforced glass fibers with epoxy resin. This results in a structure with a good strength-to-weight ratio that’s insulated against electricity. Both filament and convolute winding processes utilize a mandrel around which the glass epoxy tubing is wound, with the resin binding the glass fibers, which provide the tubing with its thermal stability, mechanical strength and chemical resistance. These material traits make it a standard choice for many industrial applications.

Filament wound glass epoxy tubing is made by winding glass fibers that are pre-impregnated with epoxy resin, also known as prepreg, around a mandrel that rotates these strands in a specific pattern. This results in glass epoxy tubing that resists pressure optimally and which is lightweight yet durable, along with having high hoop and tensile strength. Convolute wound glass epoxy tubing uses either paper or fabric infused with epoxy glass fibers that’s made by spirally wrapping it around a mandrel so that each piece overlaps. The glass epoxy tubing resulting from convolute winding can better control the thickness of the tubing’s walls, good dimensional stability and excellent compression strength.

Along with its resistance to environmental degradation, epoxy glass tubing’s electrical insulation characteristics and high strength-to-weight ratio make it a preferred option for many industries. For the electronics industry and electrical applications generally, it serves to insulate components from high voltages, such as supports for circuit boards and bushings for transformers. In the defense and aerospace industries, missile casings and structural elements of aircraft use epoxy glass tubing. Epoxy glass tubing is used as high-pressure tubing and with downhole tools for oil and gas extraction, while watercraft utilize it for corrosion-resistant structural components. In fact, many industries use epoxy glass tubing due to its durable and nonconductive qualities.   

Filament Wound Glass Epoxy vs. Convolute Wound Glass Epoxy Tubing 

There are several key differences between the construction of filament wound glass epoxy and convolute wound glass epoxy tubing that make each construction method better for certain applications. Filament wound glass epoxy tubing is made with continuous glass fibers that have been impregnated with epoxy resin. These are wound with precision around a mandrel in a hoop or helical pattern, which makes the tubing both stronger and stiffer. The angles at which the glass fibers are wound can also be adjusted to bring out specific mechanical properties, such as hoop strength and axial stiffness. The resin within the glass epoxy tubing undergoes a controlled curing process that results in a seamless structure that’s incredibly strong.  

Convolute wound glass epoxy tubing is made with glass-infused paper or fabric wrapped around a mandrel in a pattern where each piece overlaps. These layers are stacked and aligned either spirally or helically, with each layer bonded by the epoxy resin to the next. Epoxy glass tubing made in this way is cured under pressure to ensure each layer adheres well with those it overlaps. The convolute winding method allows thicknesses to be precisely controlled, while enabling multiple types of fiber orientations. While convolute wound glass epoxy tubing offers a more flexible and cost-effective means to handle moderate loads with better machinability, filament wound glass epoxy tubing provides better pressure resistance and a higher strength-to-weight ratio.  

Advantages & Disadvantages of Filament Wound Glass Epoxy Tubing 

The unbroken fibers of filament wound glass epoxy tubing contribute to its superior strength-to-weight ratio. Meanwhile, the flexibility in fiber orientations make it possible to optimize mechanical traits of the tubing. There are both advantages and disadvantages to using glass epoxy tubing made via filament winding.

Advantages of filament wound glass epoxy tubing involve: 

  • Corrosion resistance: Epoxy resin is resistant to chemicals, environmental degradation and moisture, all of which can cause material to corrode.
  • Fatigue resistance: With its greater durability, the continuous fibers involved in filament wound glass epoxy tubing make it more resistant to fatigue when under stress.
  • Fiber orientation: The orientation of fibers is flexible, allowing adjustment of the angle at which it’s wound to increase hoop or axial strength.
  • Strength-to-weight ratio: As the filament winding process improves the orientation of fibers, filament wound glass tubing has exceptional strength for its weight.
  • Structural integrity: The continuous fibers used to reinforce the tubing give it material properties that enhance its structural integrity, including higher comprehensive and tensile strength.
  • Wall thicknesses: The precision in which tubing is wound by this technique makes walls of uniform thicknesses, which in turn enhances dimensional stability.

Disadvantages of filament wound glass epoxy tubing involve: 

  • Designs: There are limitations to designs when comparing filament wound glass epoxy to convolute wound glass epoxy or other manufacturing techniques.
  • Fabrication: The complexity of this manufacturing process requires incredible precision when applying resin or controlling tension of the fiber, which means production takes longer.   
  • Impact resistance: Though this technique results in a material that resists compression and tension well, filament wound glass tubing is predisposed to experience damage from localized impacts.
  • Machinability: There are limitations because of the high fiber content that makes it exceedingly difficult to drill, cut or otherwise alter filament wound glass tubing without specialized tooling.
  • Production costs: Because the process requires specialized tooling and other equipment, this method is significantly more expensive.

As filament wound glass epoxy tubing has its advantages and disadvantages, so too does convolute wound glass epoxy tubing.

Advantages & Disadvantages of Convolute Wound Glass Epoxy Tubing

With convolute wound glass epoxy tubing, there’s more flexibility when layering material. This enables greater control over the thickness of walls and stiffness of the material. It’s a simpler technique that costs less than filament winding, which also allows better machinability. This enables manufacturers to make drilled features and customize shapes more easily.

Advantages of convolute wound glass epoxy tubing involve:

  • Adaptability: Glass epoxy tubing made via convolute winding techniques can be used for a range of industrial components like bushings and structural tubing.
  • Dielectric properties: Convolute glass epoxy tubing is suitable as electrical insulation as due to its dielectric traits.
  • Impact resistance: The layered construction of convolute wound glass epoxy tubing gives it greater toughness and makes it more resistant to impact.
  • Machinability: Unlike filament wound glass epoxy, convolute wound glass epoxy tubing can be more easily drilled, cut and otherwise altered.
  • Production costs: The simpler fabrication process makes this technique more cost-efficient for making glass epoxy tubing.
  • Wall thicknesses: This method allows for varying wall thicknesses, making it more flexible mechanically and for insulation.

Disadvantages of convolute wound glass epoxy tubing involve: 

  • Delamination: The layered structure of convolute wound glass epoxy tubing makes it more susceptible to separation or peeling under certain conditions.
  • Fiber orientation: Due to the layering process involved in convolute winding, fibers can’t be aligned precisely, which makes it difficult to optimize for specific load conditions.
  • Hoop strength: For high-pressure applications, convolute winding of glass epoxy tubing is less effective due to lower hoop strength.
  • Performance: Comparing the performance of filament wound glass epoxy to convolute wound glass epoxy tubing shows that the latter underperforms against the former when faced with continuous or inconsistent stress.   
  • Strength-to-weight ratio: As the fiber structure isn’t continuous with convolute winding, glass epoxy tubing has lower compressive and tensile strength when compared to filament winding.  

When comparing filament wound glass epoxy vs. convolute wound glass epoxy tubing, each method’s strengths make it ideal for certain applications.

Ideal Applications: Filament Wound Glass Epoxy vs. Convolute Wound Glass Epoxy

Both filament wound glass epoxy and convolute wound glass epoxy tubing have applications for which they’re ideally suited. Filament winding is ideal as structural supports and electrical insulation, as well as for high-pressure applications.

Ideal applications for filament wound glass epoxy tubing include: 

  • Aerospace structural components
  • Deep-sea oilfield pipes
  • Electrical insulation
  • High-pressure piping and tanks
  • Hydraulic cylinders
  • Industrial rollers and shafts
  • Lightweight composite shafts
  • Military-grade tubing
  • Sporting equipment like bike frames and fishing rods

Convolute wound glass epoxy tubing is used in applications where strength is less important, including for applications involving low to moderate pressures. In particular, this technique works well when tubing needs to have walls with varying thicknesses.

Ideal applications for convolute wound glass epoxy tubing include: 

  • Bearing sleeves
  • Bus bars
  • Electrical conduit systems
  • Electrical insulation
  • Insulating sleeves
  • Lightweight structural components
  • Mechanical spacers
  • Protective casings
  • Reinforcing structures
  • Transformer bushings

In a nutshell, filament wound glass epoxy tubing has a high strength-to-weight ratio, is resistant to pressure and offers excellent strength, while convolute wound glass epoxy tubing offers better cost-efficiency, machinability and versatility.

Glass Epoxy Tubing from Spaulding Composites

Spaulding Composites Inc. fabricates glass epoxy tubing through either filament or convolute winding methods. We make filament wound glass epoxy tubing with custom-designed mechanical and thermal properties for the application. Additionally, our company can manufacture convolute wound glass epoxy tubing up to 48 inches (121.92 cm) in length, with inside diameters down to 0.125 inch (3.175 mm) for fabrics or 0.250 inch (6.35 mm) for paper, and outside diameters up to 18 inches (45.72 cm). For advice on whether filament wound glass epoxy vs. convolute wound glass epoxy tubing is best for your application, contact the composite experts at Spaulding.