Fiberglass Fabrication 101

Fiberglass fabrication plays a critical role across industries where corrosion resistance, structural reliability, and custom geometry matter. From industrial chemical tanks and wastewater components to shipping enclosures, aquatic features, and aviation parts, fiberglass is often selected because it performs where traditional materials fall short.

Despite being so popular, the fabrication process for fiberglass products is relatively unknown. This guide provides a foundational overview of fiberglass fabrication to help engineers and procurement teams understand where fiberglass fits, what factors influence performance, and how it’s commonly applied across real-world projects.

How is Fiberglass Fabricated?

Fiberglass fabrication typically relies on various molding processes that shape and support the part while layers of glass reinforcement and resin are applied. Molds define the final geometry, surface finish, and dimensional consistency of the component, making them central to most fiberglass production.

Within molded fabrication, different reinforcement and resin application techniques are used depending on part size, performance requirements, and production volume. Two common approaches are hand layup and chopper spray application:

• Hand layup. Hand layup involves placing fiberglass mat or cloth into a mold and saturating it with resin by hand. This approach allows for precise control over fiber placement, reinforcement patterns, and localized thickness. It’s commonly used for prototypes, low-volume production, mold making, and areas of a part that require specific structural properties or a higher-quality finish.
• Chopper spray. Chopper spray uses specialized equipment to cut continuous glass fibers and spray them with resin directly into a mold. This technique efficiently builds thickness over larger surface areas and supports consistent material distribution, making it useful for increasing production efficiency while maintaining structural performance.

In practice, fiberglass components are rarely produced using a single technique alone. Most parts rely on a combination of molding and layup methods selected based on the specific requirements of the application. Common molding techniques include:

• 3D molding for creating complex, multi-dimensional fiberglass components
• Flat molding for producing uniform fiberglass panels
• Structural foam molding for producing strong yet lightweight fiberglass parts with foam cores
• Transfer molding for creating parts with consistent material distribution and improved structural integrity
• Vacuum bag molding for creating fiberglass components with enhanced strength and minimal voids

Materials for Fiberglass Fabrication

Material selection directly impacts how your fiberglass part performs in real-world conditions. Resin choice, in particular, plays a central role in determining how a finished part responds to its operating environment. While many resin systems are available, fiberglass fabrication commonly relies on:

• General-purpose resins. These polyester-based resins provide cost-effective performance for standard environments where exposure to high temperatures or aggressive chemicals is limited. They are often used when structural demands are moderate and environmental conditions are well controlled.
• High-temperature resins. High-temperature resin systems are formulated to maintain mechanical strength and dimensional stability at elevated operating temperatures. These resins are selected when components are exposed to sustained heat or thermal cycling that would degrade standard formulations.
• Vinyl ester resins. Vinyl ester resins offer enhanced resistance to corrosion, chemicals, and moisture. They are commonly specified for applications involving acids, solvents, or other harsh substances where long-term durability is critical.

Beyond resin selection, fiberglass materials include a range of glass fiber reinforcements (mat, woven roving, and cloth), each contributing different strength, stiffness, and surface characteristics. Additional additives or coatings may also be incorporated to improve UV resistance, flame retardancy, or other performance requirements.

Applications and Uses of Fiberglass

Fiberglass is commonly used where traditional materials struggle with corrosion, weight, or complex shapes. A few common examples include:

• Industrial manufacturing. Fiberglass performs well in environments exposed to moisture, chemicals, or frequent washdowns, offering corrosion resistance and dimensional stability where metal can degrade over time.
• Aviation. Its strength-to-weight ratio makes fiberglass suitable for components where weight reduction is important without compromising structural integrity.
• Wastewater treatment. Continuous chemical exposure can quickly degrade conventional materials. Properly formulated fiberglass maintains performance and durability in corrosive environments.
• Pool, spa, and aquatic applications. Fiberglass is often chosen because it maintains performance when exposed to constant moisture. This makes it well-suited for slides, diving boards, and other pool or aquatic features that require durability and consistent structural integrity over time.

Contact CMDT Manufacturing to Get Started

Fiberglass fabrication works best when material selection, molding approach, and performance requirements are aligned early. The right fabrication partner helps turn those decisions into durable, reliable parts.

CMDT Manufacturing has fabricated quality fiberglass components since 2008, offering in-house mold making and fabrication capabilities that support consistent results from start to finish. Contact CMDT Manufacturing today to discuss your project or request a quote.