Fiberglass Fabrication

Of the fiberglass fabrication processes, fiberglass molding is the most commonly used process in the creation of fiberglass reinforced plastic products. The fiberglass itself is made of molten glass extruded through ultra fine openings in a tool, resulting in thread-like formations that are then woven together to form a rough cloth or patch. These fibers are combined with plastic resin by heat treatment or pressing. This process is used to form many different fiberglass products, including panels, shells of racing cars, electric circuit boards, machinery support and an extensive variety of other products. Fiberglass does not expand or shrink with temperature change. It is not water absorbent, has a high strength-to-weight ratio, is nonflammable and chemical resistant and acts as an electric insulator. Fiberglass fabricators manufacture various types of fiberglass products. One prominent example is corrugated fiberglass, which is made up of two-layer fiberglass sheets and fiberglass panels and is used in building construction. Fiberglass enclosures like fiberglass tanks and fiberglass boxes are other important fiberglass products. Other examples of fiberglass reinforced plastics include fiberglass pipes and fiberglass rods.

There are a number of different types of fiberglass and resins used to make fiberglass materials and products with different strengths, aesthetics and applications. Fiberglass is classified into seven main types. E-glass is the most common glass reinforced plastic variety, A-glass is characterized by low boron oxide concentration, E-CR-glass has a high acid resistance, C-glass is used for glass staple fibers, D-glass features a high dielectric constant, R-glass is known for its exceptional mechanical properties and S-glass is known for its very high tensile strength. These fiberglass types are mixed with thermosetting resins, which are usually made of epoxy or polyester. Resins are used for molding, laminating and casting. Epoxy resin has a higher performance and therefore a higher cost, and it is used in weight-critical, high strength applications. Polyester resins are less expensive, more widely used and have good resistance to corrosion.

The three main methods of fiberglass fabricating are open molding, closed molding and centrifugal molding. In open molding fiberglass fabrication, a layer of gel coat is applied and cured in a one-piece mold or structure. After being layered into the mold, the fiberglass and sprayed resin are allowed to cure. Open molding releases more emissions than the other two processes. In closed molding, the initial gel coat is applied in a two-part mold. Fibers in the form of chopped fibers or laminated sheets are sprayed or placed in the female part of the mold on top of the gel coat. The part cures after being sealed in the mold by a vacuum and catalyzed resin is injected into the pressurized mold. In centrifugal molding, the gel coat is applied to the sides of a spinning cylindrical mold. Layer by layer, catalyzed resins saturated with short fibers are sprayed into the mold until desired thickness is reached. Centrifugal molding is used to form cylindrical products, such as pipes and tanks. In all processes, the end products are then demolded and trimmed. Corrugated fiberglass is perhaps the most widely used fiberglass product used today. It is strong, may be either a solid color (often green) or transparent for light transmission into buildings. It is mostly used in building construction to make siding or roofing, and it is often used to build greenhouses and sheds. Corrugated fiberglass is generally composed of two layers that are glued together. The outer layer is a hard, weather-resistant resin surface, while the other layers are made of fiberglass.

Fiberglass is often a superior material in comparison to many others, specifically aluminum, which is the main alternative to fiberglass. Pultruded fiberglass shapes have several advantages over comparable aluminum extruded shapes. Pultruded fiberglass has superior resistance to a wide variety of chemicals. Fiberglass shapes are about 70% of the weight of aluminum shapes but with the same density. Pultruded fiberglass is non-conductive with a high dielectric capability, while aluminum is a conductor. Fiberglass is a much better insulator than aluminum, as it has much lower thermal conductivity. Pigment added to the resins of fiberglass can provide color throughout the part, while aluminum requires prefinishing, anodic coatings or paint. Fiberglass is transparent to radio waves and EMI/RFI transmissions and is often used for radar and antennae enclosures and supports. Aluminum is highly reflective, making it inappropriate for such applications. Pultruded fiberglass shapes can be easily fabricated in the field with common carpenter tools and do not require torches or welding. Finally, the glass mat in pultruded fiberglass shapes evenly distributes the load of an impact, while aluminum easily deforms. Fiberglass reinforced plastic is an excellent construction material for an extensive range of products.

Images Provided by All Plastics and Fiberglass, Inc.

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Types of Fiberglass Fabrication

• Corrugated fiberglass products are waved or ridged, two-layer fiberglass reinforced plastic sheets. 
• Fiberglass boxes are square or rectangular-shaped storage and transportation tools made of fiberglass reinforced plastic.
• Fiberglass enclosures are tanks or storage areas fabricated of fiberglass. Food industries, chemical plants and water treatment facilities use fiberglass enclosures.
• Fiberglass fabricators are companies that produce fiberglass reinforced plastic products as well as fiberglass for other applications like insulation.
• Fiberglass grating is composed of a series of parallel and intersecting parallel lines of fiberglass.
  
• Fiberglass molding including open, closed and centrifugal molding, shapes fiberglass products using a hollowed form. The mold from which the fiberglass is created is usually a metal.
• Fiberglass panels are planes or sheets made of fiberglass reinforced plastic.
• Fiberglass pipes are hollow channels made of fiberglass reinforced plastic.
• Fiberglass products are made of a mix of glass fibers and resins.
• Fiberglass reinforced plastics are plastics that have been combined during a plastic thermoforming process with extruded glass fibers in order to improve the plastic's qualities of strength and durability. 
• Fiberglass rods are thin, often rounded shafts that are made of fiberglass reinforced plastic.
• Fiberglass sheets are sheets made of a mix of fine filaments of glass and resins.
• Fiberglass storage boxes are heavy-duty, durable, waterproof units that are used to store such things as fishing tackle, pool equipment and paint and liquid products. Larger storage boxes may also double as seating.
  
• Fiberglass tanks are fiberglass containers ranging in size that are used to store gases, liquids and sometimes solids. Many food plants and chemical plants will make use of fiberglass tanks.

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Fiberglass Fabrication Terms

Aspect Ratio - Generally, the ratio of diameter to length. In composites, it is the ratio of the fiber or filler in the composite matrix.
 
Bondable - Capable of being secured or fastened using a bond or rope. Fiberglass is bondable because the resins and glass that are combined to create fiberglass are bond forming.
 
Catenary - The act of creating or maintaining equal tension in parallel fibers. Catenary also refers to having the property of this tension.
 
Chopped Strand Mat - A reinforcement of fiberglass that uses short strands of continuous rovings arranged in random order and held together with a binder.
 
Composite - Amaterial, such as fiberglass reinforced plastic (FRP), composed of two or more distinct substances. They combine to form functional or structural characteristics not available with a single material.
 
Compression - The process of increasing density of materials. As with fiberglass laminates, compression results in the product becoming smaller and pressed together.
 
Continuous Roving - Sizing-coated parallel filaments drawn together into single or multiple strands and wound into a cylindrical package.
 
Cupola - Also referred to as a "dome," it is an upside down-shaped cup made of fiberglass, which covers the tops of buildings, churches and other forms of architecture.
 
Epoxy - A common surface coating that forms a tight surface structure, is strongly adhesive and shrinks little, if at all.
 
Fiber - General term for a filamentary material whose length is at least 100 times its diameter. Fiber also refers to parts of a single unit of a substance that forms threads to be woven.
 
Fiberglass Reinforcement - Common material used to reinforce plastic.
 
Filament - The smallest unit of a fibrous material that is formed by spinning or drawing it into a single, long, continuous entity.
 
Filament Wound Tubing - Tubing that consists of finely spun fibers in a uniform structure.
 
Filler - An inorganic addition, especially particulate additives, to the composite matrix in order to improve the performance of the product, such as in shrinkage control, surface smoothness and water resistance.
 
Glass - Any of a large class of materials with varying optical and mechanical properties that is generally hard, brittle and translucent or transparent and considered to be a super cooled liquid, as opposed to a solid. Glass fibers, when mixed with various resins, are the main ingredients in a fiberglass product.
 
Glass to Resin Ratio - The amount of glass compared to amount of resin in a fiberglass product. Generally, the higher the concentration of glass, the greater the strength and durability.
 
Laminate - A thin fiberglass sheet or plate created by compression. Laminates sometimes consist of several thin layers.
 
Polymer - One of many synthetic and natural compounds of high molecular weight. They are composed of millions of repeating links, each considerably light and simple.
 
Resin - Any of numerous translucent yellow or brown to clear, semisolid or solid substances of plant origin, such as amber and copal. Resins are used in synthetic plastics, inks, lacquers, adhesives, etc.

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