Author: AKeson

Plastic Skin

One of the other synergies of FRP composites is its use as a reinforcement behind thermoplastic decorative skin layers. A thermoformed ABS or ABS blend plastic is made as the surface of the part. Then it can be reinforced on the backside with fiberglass construction. Vinylester and ABS resins adhere very well with each other and create a strong bond. The FRP will then provide all of the strength and support that it is designed for, while the thermoplastic skin is more damage and impact resistant than gelcoat. My experience leads me to think that the largest use of this technology is in bathtub and hot tub applications. High volume manufacturers can setup to make large numbers of thin thermoplastic skins. These are then setup on holding jigs to keep their shape while fiberglass resin and reinforcement is used to permanently lock the shape together. This method allows for nicer surface finishes, can save cost depending upon volume, allows for fewer cracking issues, and can offer different coloring...

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Role of Gelcoat

Gelcoat is the decorative surface found on fiberglass parts such as boats, bathtubs, and restaurant seats. This outer layer is needed for aesthetics and protection of the underlying laminate structure. Chemically it is unsaturated polyester/vinylester resin that is unreinforced but heavily filled with a complex variety of additives. These additives are used to determine its color, UV stability, and chemical resistance. The manufacture of fiberglass parts typically requires a gelcoat layer to aid in the release of the parts from the mold. The parts that will be painted also are manufactured with gelcoat but it is a “sandable” variety. These parts are often automotive-related, and may include pickup truck toppers, fiberglass kitcar bodies, and other aftermarket add-ons such as running boards or hood scoops. The unsaturated polyester/vinylester gelcoat is directly compatible with resins and laminate of the same chemistry. Gelcoat can be used with epoxy resins but requires a tiecoat for adhesion because of the chemistry difference. Gelcoat is applied at 18 to 25 mils (thousandths) and will lose thickness as it cures. Typically when it is dry on the part, it can be down to 12 to 18 mils. This is a lot thicker than a painted surface. One of the disadvantages of gelcoat is that it can be more difficult to repair, especially with color matching. The thickness typically allows for sanding out scratches and blemishes, but...

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Industrial Corrosion applications

A lot of FRP materials are used in the chemical and industrial sectors of the economy. The non-corrosive and non-conductive properties of the fiberglass materials have many advantages over steel and other materials. Large tanks, pipes, and structures are fabricated both off-site and on-site of the final installation. The best quality comes from the controlled environment of the factory. However, the physical size may necessitate that structures are built in pieces for transport and installation. They onsite workers can join the pieces to become one. There are several joining methods, including adhesive, mechanical, and chemical bonding (fiberglass tabbing). There are specialized resins used for these corrosion New events, new promotions and new bonus opportunities are constantly entering the Platinum Play fold. applications. These resins are the best at resisting chemical interaction, and are made to have high impact strengths to resist failure of the overall structure. Fiberglass resin and glass is normally non conductive, both with heat and electricity. This can be adventageous for negating concerns for electrocution. The flipside is that static electricity can build up and discharge randomly in a search for a grounding path. Heat conduction is poor so it can act as an insulator and heat sink. Many of the pipes and tanks are manufactured using a process called filament winding. This is a process where a round mandrel acts as a mold and rotates...

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Bagging/Infusion On The Cheap

Vacuum Infusion and Vacuum Bagging can be accomplished are not only reserved for industry and can be accomplished in a workshop setting. Relatively inexpensively as well. One of the major variables is the shape of the part trying to be built. We will look at a flatstock for now. The desired outcome could be either a test panel or a piece needed for flat construction. The mold will be the difference between this and any other more complicated shape. The mold must be able to be sealed from the atmosphere and waxed for release of the finished part, so my favorite “mold” is either a flat sheet of steel or a sheet of plate glass depending upon desired surface finish. This must then be waxed up with some paste wax to enable part release. I always like to start with creating the perimeter seal. The 1/8 or 3/16 inch thick by 1/2″ wide gray butyl tape is the best. This is basically sticky on both sides and has wax paper on one side. It is sold at infusion suppliers or online as well. My little secret is that it is also sold at building supply stores, as it is used on polebuilding construction projects when sheets of steel siding/roofing are sealed together with this stuff. So this is unrolled and pushed down onto the mold and the wax paper...

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Vacuum Infusion Processing

Resin infusion processing offers several advantages over traditional open mold processing techniques. All of the reinforcements and core materials are placed in the mold without resin, so care can be taken for close fit and proper orientation. And it is a lot cleaner without the sticky resin. Resin waste is typically lower because all of the resin is added at once. VOC”s are reduced as well, and are only emitted from the open mixing containers. There is much less worker interface with messy and stick resin on people and tools so cleanup materials and personal protection equipment expenses are reduced. The laminate itself is typically more consolidated, uniform, and visually pleasing. One of the considerations that needs to be taken into account is that the ratios are different and the glass and resin are more compacted by the process. Using the same layup schedule would result in a thinner laminate that is lighter weight and uses less resin. One drawback to this is that the cross sectional area is less, usually resulting in a loss of stiffness. This can be regained by increasing the core thickness to compensate for that loss and to restore overall panel thickness. Infusion processing does require specialized equipment, consumables, and materials. The resins need to have much lower viscosity(flow like water). The core and glass need to have holes and channels for the resin...

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