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What's The Difference?

In some ways, thermoforming and fiberglass are similar processes. Both have lower startup costs than other processes, enabling cost-effective creation of lower quantities of parts. But they also have some distinct advantages and disadvantages. Our chart will help you understand some of those differences.


Thermoforming vs. Fiberglass Guide

Process OverviewA plastic production process that heats a rigid 2-dimensional sheet and uses vacuum and/or pressure to form that sheet against a mold into a 3-dimensional shape. Fiberglass reinforced resin is formed into 3-dimensional shapes. The resin is applied in multiple layers to build up strength and achieve the desired thickness.
VolumeMost cost effective in production volumes from hundreds to mid thousands. Used mainly in prototyping and smaller production runs
  • TPO, (Thermoplastic Poly Olefin) is a popular material choice for replacing fiberglass. TPO is more durable, crack and UV resistant and significantly lighter when compared to its fiberglass counterpart.

  • Hundreds of material options in colors, textures, thickness and specialty features like chemical resistance, flammability ratings and many more.

  • A choice of fiber materials, fiber weave and either polyester or epoxy composite materials.
Finished Part Weight
(See Specific Gravity Graph)
Up to 35% LighterUp to 35% Heavier
Finishing Options
  • Can be molded in color & texture.

  • Offers a high quality unpainted finish.

  • Can be painted or silkscreened.

  • Can easily create high-gloss scratch-resistant finishes.

  • Metallic options available.

  • Must be painted.

  • Limited options for high-gloss scratch-resistant finishes.

RecyclabilityBoth final thermoformed parts and excess material are fully recyclable. The final parts are non-recyclable, and the process uses a significant amount of hazardous materials.
Labor Costs & Lead TimesThermoforming is a highly automated process, particularly at state-of-the-art facilities like Ray Products. Most parts are made from an aluminum tool, which decreases lead times and provides lower labor costs. From a processing standpoint, thermoforming is faster and less expensive in volumes of high hundreds to mid thousands.Fiberglass molding is a very labor intensive process and often requires multiple tools for the production of a single part which results in slow production output, higher costs and longer lead times compared to thermoforming.
Tolerances & Complex GeometryThermoforming can support the tight tolerances and complex geometries necessary to create mating parts. It’s difficult to support the complex geometries and tight tolerances necessary to create mating parts with fiberglass molding.
Part-to-Part Repeatability*******
Impact Resistance*******
UV Resistance********
Molded-In Features*******

The specific gravity of a material is useful in comparing the weight of different materials. A lower specific gravity will result in a lower weight for an equal amount of material.

By looking at the specific gravity of common thermoplastics used in thermoforming and comparing them to the specific gravities of common fiberglass materials, we can easily see the benefits offered by thermoforming.


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