How to Choose the Resin

Resin selection can vary from fabric compatibility, service conditions, and desired characteristics of the finished part. There are generally three types of thermosetting resin to consider when approaching your project: Epoxy, Vinyl Ester, and Polyester. Let’s take a look at each of the choices, their characteristics, and what they should be used for.

1. Epoxy Resin

For composite parts that demand the ultimate strength, fabricators will use an Epoxy Resin. In addition to increased strength properties, epoxies also generally outperform polyester and vinyl ester for dimensional stability and increased bonding with other materials.

Pros: 

Epoxy Resin, High Strength Properties, Can be used in vacuum infusion applications, Easy to handle, Medium viscosity

Cons: 

Cannot be used with chopped strand mat

Not UV stable. This must be paired with a top coat when exposed to UV rays

2. Polyester Resins

Polyester Resins are the most widely used resins in the composites industry. Polyester Resins are less expensive, offer some corrosion resistance, and are more forgiving than epoxies. The majority of all fiberglass parts are constructed using Polyester Resins because they are easy to use, fast curing, and tolerant of temperature and catalyst extremes. Fibre Glast carries two different types of Polyester Resins, each with their own strengths and uses.

POLYESTER MOLDING RESIN

Pros:

Inexpensive, Easy to handle, Rapid wet-out, High thixotropic index (product won’t run on vertical surfaces)

Cons:

lower physical properties compared to more expensive resins

ISOPHTHALIC POLYESTER RESIN

Pros:

Dimensionally stable (minimal shrinkage), resists post cure problems, can be used in food contact applications

Cons:

Slightly more expensive than general purpose polyester resins

3. Vinyl Ester Resin

Vinyl Ester Resin is considered a hybrid of polyester and epoxy—meaning its handling characteristics, properties, and price generally fall just between the other two. It is important to note that, Of the three, vinyl ester resin will provide the highest corrosion resistance, temperature resistance and elongation (toughness.) Because of this, they are typically used when high durability, thermal stability, and corrosion resistance is needed.

Pros:

Vinyl Ester Resin, Extremely tough, corrosion resistant, heat resistant

Cons:

Short shelf life (3 months)

A Simple Female Mold Construction with Fiberglass

Composite materials offer ability to be molded to complex shapes is perhaps the most popular. When a shape needs to be reproduced numerous times, it is most efficient to build a tool or mold within which the part can be fabricated. Molded parts emerge perfectly shaped every time and require little post-finishing work.

Molding or “stamping” has been used for years to shape metal products like car bodies, home appliances, and industrial fixtures. Metal stamping dies are cumbersome and cost thousands of dollars to produce. Only large companies can afford to build, operate, store, or even move these tools. Composite materials offer a cost effective way for anyone to make even large production runs of identical plastic parts in molds they can produce themselves.

Female molds or cavity molds offer numerous advantages for medium to large production runs. Finishing time is significantly reduced because every part emerges with a smooth outer surface.

PRODUCTS FOR MOLD CONSTRUCTION 

Duratec Gray Surfacing Primer

Modeling Clay

Parting Wax

PVA Release Film

Tooling Gel Coat

Chopped Strand Mat

Tooling Fabric

Woven Roving

10 oz Fabric

Polyester Molding Resin

Comparison between Fiberglass and Carbon Fiber

Fiber fabric and the resin are the general two parts of composite materials, with the physical properties of the material being fiber dominant. What that means is, when the resin and fiber are combined, their performance will primarily depend upon the fiber used. Test data shows that the fiber reinforcement is the component that will carry the majority of the load within the composite. So what does that mean? Well. Simply put, what fabric you choose is going to matter.

The two most common types of fabric in the industry are fiberglass, and carbon fiber. Both have a wide assortment of usages, and are extremely versatile. How do the two weigh up against each other? While comparing the two, Keep in mind, both fiberglass and carbon fiber will vary depending on the fabric you choose. A lightweight 2 oz Fiberglass Fabric will not have the durability of the more structural 10 oz Fiberglass Fabric. Additionally, the weave of the fabric and the resin used will have a large impact on the strength and properties of your composite product. 

Fiberglass

Fiberglass is the most widely used fiber in the industry, and with good reason. Fiberglass is versatile, easy to handle and relatively inexpensive compared to its counterparts. Fiberglass is perfect for every day projects that are not expected to need the added strength and durability of higher priced fabrics. Fiberglass is compatible with most resins, and comes in a multitude of patterns and weaves.

Carbon Fiber

Carbon Fiber is far and away the premium end for composite materials. With excellent ultimate tensile strength, along with the greatest compressive, flexural, and bend strength in the industry, carbon fiber is the go to on projects that need to be built tough. Carbon Fiber is ideal for projects that need that added “umph” of strength, so long as you can handle the corresponding “umph” to your wallet. With its distinctive design look, carbon fiber is a popular choice in a multitude of industries, including the automotive and aerospace sectors.

More information regarding fiberglass, please visit chopped strand mat manufacturer-wbcomposites.com

Glass Fiber VS Carbon Fiber

Glass Fiber and carbon fiber are widely used in composites these years. So what’s the difference between them?

WEIGHT

Glass Fiber Carbon Fiber Comparison So how do the two match up, against each other? For one,  Glass Fiber fabric is much less efficient in it’s density, when compared to it’s composite counterparts. While Glass Fiber is still significantly lighter than conventional materials (wood, steel, etc) for it’s given strength, on weight critical projects carbon fiber will preform much better as a reinforcement.

STRENGTH AND DURABILITY

Similarly, carbon fiber will outperform Glass Fiber in it’s tensile strength (the amount of force that needs to be placed on a fiber in order to pull it apart) and compressive strength (the amount of force that presses down on a fiber). However, Glass Fiber is more “durable” in that you can bring Glass Fiber near to it’s breaking point repeatedly without much cause for concern, unlike carbon fiber.

MODE OF FAILURE

Additionally, once carbon fiber reaches it’s breaking point, the mode of failure is catastrophic (it will fracture/shatter the piece.) Glass Fiber on the other hand, will develop cracks or deform before it breaks.

COST

Unfortunately, due to the nature of carbon fibers, it is much more expensive compared to its counterparts. So if your project isn’t weight dependent, and won’t need the excellent strength that comes from carbon fiber, Glass Fiber is a great choice to go with. 

This article is from fiberglass chopped strand mat manufacturer wbcomposites.com .

Use GRP for Antwerp Zoo Aquarium’s Renovation

Antwerp Zoo has used these materials for making moulds and grids as part of the renovation work carried out in the aquarium. Thanks to the outstanding properties of glass fibre reinforced plastics they can be used for a wide range of applications.

Glass fibre reinforced plastics (FRP) are composite materials made from glass fibres and resin, where the (glass) fibres give the material its strength and the resin provides resistance to chemicals. Moreover, this combination of materials results in a strong, lightweight material, which is suitable for a wide range of applications, also in salt water environments.

The Antwerp Zoo aquarium is over a hundred years old, making it one of the oldest in Europe. Naturally it has been renovated a number of times, including recently. The time taken to complete the renovation was three years. Glass fibre reinforced plastic played a significant role in this extensive project.

The new, large tank at the rear of the building is the culmination of the entire renovation project and was designed to become the main attraction and crowd-puller for visitors to the aquarium. The tank is 12 metres wide, 6 metres long and 4.5 metres in height. In order to accurately replicate the biotope of the fish, the initial idea was to create a coral reef using blocks of moonstone. But because this was going to weigh approximately 35,000 kilograms, an alternative had to be found. Glass fibre reinforced plastic provided the solution.

It was decided to make the ground structure from plastic with glass fibre reinforced plastic grids fitted on top, over which coral moonstones could be laid. This resulted in the total weight of the structure being reduced to 10,000 kilograms. The second important reason for using a glass fibre reinforced plastic structure was that the tank had to be filled with salt water. This ruled out using metal components. 

Therefore the glass fibre reinforced plastic structures provided the ideal solution. The entire FRP structure is kept in place with plastic anchors and bolts. The grids are fixed to the load-bearing structure by way of a nylon rope.

For the very same reasons, glass fibre reinforced plastic has been used for parts of the aquarium not visible to the visitors. All the tank covers in the aquarium building are also made from FRP.

WHY CHOOSE FIBERGLASS POOLS

Fiberglass Pools are an eco-friendly alternative to traditional (concrete) pools. Choosing an Fiberglass Pool is an environmentally responsible choice.

Fiberglass Pools have low embodied energy. Embodied energy is defined as “the total energy required to produce a product from the raw materials through delivery”.

Fiberglass Pools are a great insulator against heat and cold. Fiberglass helps to conserve energy while reducing operating cost.

Fiberglass Pools are made from super durable materials with an indefinite life cycle. This eliminates replacement cost and expensive repairs. You won’t find fiberglass Pools going into a land fill like a broken out concrete structure.

Fiberglass Pools’ main ingredient is fiberglass and fiberglass chopped strand mat which is made from sand that is an abundant resource.

Fiberglass Pools use less chlorine and other chemicals due to the inert smooth interior finish as compared to concrete pools.

Fiberglass Pools do not emit chemicals into the pool water or the soil behind it. Concrete pools emit alkaline, calcium, lye, and other chemicals into the pool water and adjacent soils.

So make your next pool a Fiberglass Pool that will provide your family with a lifetime of enjoyment and will be a beautiful addition to your yard. It will also be an environmentally sustainable green product that will not hurt our precious environment.

Composites Keep Building from Falling in Seismic Events

Concrete buildings are losing the battle against nature’s fury – earthquakes. Although they appear sturdy, older concrete buildings are vulnerable to the sideways movement of a major earthquake. Los Angeles officials have known about the dangers for more than 40 years but have failed to force owners to make their properties safer. Therefore, university researchers compiled a list of potentially dangerous concrete buildings within the city. Their findings point to the fact that society needs to deal with retrofitting structures.

So what does this have to do with FRP composites?  Well, everything.

Since the late 1980’s, when glass fiber reinforced polymer (FRP) composites were first applied as external strengthening systems to rehabilitate and repair reinforced concrete, the construction industry has embraced these materials as an important tool in the engineers toolbox. Numerous structures have been seismically retrofitted with glass and carbon FRP composites ranging from transportation structures (columns, girders, slabs) to building structures (columns, beams, walls, floors). Both reinforced concrete and unreinforced masonry are the targets.

There are still many more structures that need to be fixed and the market potential is huge. The big challenge is where do society, federal, state, city, county and other local governments find the money to keep the public safe in seismic events. What we do know is this; there is design guidance out there provided by the American Concrete Institute (ACI) on how to design with FRP composites to repair concrete and masonry. There will soon be additional design guidance provided for seismic applications and there are a number of companies already offering these materials and products. Thousands of installations show composites are an engineered solution.

New Epoxy Resin 250°F/120°C without Oven or Autoclave

Almost resin cure slowly or need heat. Now, NONA Composites will unveil its new R404/H18 resin system at CAMX 2015.  This new epoxy resin enables room temperature infusion or filament winding followed by a relatively fast (≈ 2-hr) cure without adding any heat (i.e., no oven no autoclave) or an even faster (15-30 min) heat-added cure (250°F/120°C) with no post-cure, to enable faster, larger, and more flexible composite processing for filament wound pressure vessels, marine structures, industrial composites, and even some lower-temperature aerospace composites.

New NONA R404/H18 epoxy resin offers curing and tooling flexibility for a wide range of structures, including large marine infusions and filament wound tanks for energy applications. 

A key application of this new system will be in filament wound tanks for compressed natural gas (CNG) storage and other alternative energy markets. In order to measure the material’s performance beyond standard testing, NONA Composites worked with HyPerComp Engineering Inc. to filament wind and burst test a small composite overwrapped pressure vessel.  An aluminum liner overwrapped with T700 carbon fiber and NONA R404/H18 resin was cured using a 2-hr heat-added cure cycle at 250°F/120°C but without post-cure. (Heat was added due to the aluminum liner heat sink.) The vessel was then burst according to standard in-house HyPerComp Engineering procedures.  The comparison of delivered fiber strength to that predicted by HyPerComp's computer finite element analysis (FEA) was 102%, demonstrating its successful performance in this standard test setup.  The next step is to build and burst test the same tank using a 15-min heated cure, as NONA Composites continues working with HyPerComp Engineering to evaluate R404/H18 epoxy’s performance with fiberglass-based filament wound vessels.

In addition to the work in filament wound structures, NONA Composites is demonstrating its R404/H18 epoxy in a 500 ft2 infused hybrid fiberglass and carbon structure. The company will showcase this part production in 2016 as a demonstration of the ability to fabricate larger components more rapidly without an oven or added heat.

A New High-temperature Resistance Polymer System

Recently, CRG (Cornerstone Research Group Inc.) has introduced a completely new polymer system that has demonstrated high-temperature resistance like a polyimide (service temp. 300-450°C) as well as ultra-low flammability, heat release and smoke release, yet is similar to two-part epoxy resins in processability and cost. Moreover, these systems cure to a thermoplastic state at temperatures below 110 °C, cross-link to a thermoset at temperatures above 110 °C and can be converted to an almost pure carbon material at higher temperatures.

MG Resins can be combined with fiber reinforcement using conventional processing techniques, offering the potential for low-cost, high temperature structural composites. Water is the only volatile generated, thus processing does require management of porosity, similar to condensation-reaction polymers like phenolics and polyimides. However, initial testing of MG Resin composites shows an order of magnitude lower heat release vs. phenolics.

MG 1000 test samples were made using glass and carbon fiber fabrics and carbon fiber felt using vacuum infusion and hand layup. Carbon fiber panels and carbon felt panels were autoclave cured at 200-250°C and 100 psi with a 2-hr post-cure at either 250°C or 315°C. Glass fiber specimens were oven-cured at 250°C. MG 3000 test samples were prepared in a similar manner. Syntactic test panels were also produced using milled fiber and resin in an effort to explore low-density materials for potential use in ablative and thermal protection systems (TPS) for spacecraft. Overall, the resulting composites processed well, though further optimization of polymer formulations, processing and cure cycles is ongoing to reduce void content. Programs are also in progress to fully characterize the MG 1000 and MG 3000 resin systems and composite laminates.

E-glass Fiber Showed in IBEX 2015

International Boatbuilders’ Exhibition & Conference (IBEX) 2015 was held Sep. 14-16 in Louisville, KY. The show drew 4,700 attendees and 545 exhibitors, 110 of which were new to IBEX

COMPOSITE FABRICS OF AMERICA showed samples of new hybrid fabrics that not only offer toughness, but also truly unique aesthetics. The 2x2 twill at left features 3K carbon, aramid and E-glass fibers in a 7.3 oz (248 gsm) areal weight fabric while the 3K carbon fiber/Innegra S houndstooth at right is a 218 gsm fabric.

MAHOGANY COMPANY celebrates its 75th anniversary this year and highlighted its prefabricated sandwich panels made with a variety of skin materials, including carbon fiber, carbon fiber/E-glass hybrids and KEVLAR aramid fiber/E-glass hybrids. The panels can be cut to net-shape and kitted for boatbuilder use as doors, bulkheads, floors/soles and more. Panel skins most often feature quadraxial and biaxial noncrimp fabrics, but the company’s 4’ x 8’ and 5’ x 10’ presses are amenable to a wide range of materials, depending on customers’ needs for weight and labor savings. Renowned builder Viking Yachts is using lightweight composite panels from Mahogany in all of its models to reduce weight and boost performance.

Mahogany Company’s prefabricated composite sandwich panels with carbon fiber and hybrid skins (left).  Viking Yachts uses a variety of Mahogany composite panels, for example in the Viking 92 bulkheads (right), to reduce weight and boost performance.

Glass Fiber in Composite Material

SICHUAN SINCERE & LONG-TERM COMPLEX MATERIALS CO.,LTD. is a modern high-tech corporation which is professionally engaging in the glass fiber products exploring, designing,producing and application. The structural properties of composite materials are derived primarily from the fiber reinforcement. In a composite, the fiber, held in place by the matrix resin, contributes high tensile strength, enhancing performance properties in the final part, such as strength and stiffness, while minimizing finished component weight.

Fiber properties are determined by the fiber manufacturing process, the fiber's chemical constituents and the coating chemistries that adapt the fiber for adhesion to the resin matrix and protect it during further processing.

Glass fibers

The vast majority of all fibers used in the composites industry are glass. Glass fibers are the oldest and, by far, the most common reinforcement used in most end-market applications (the aerospace industry is a significant exception) to replace heavier metal parts. Glass fiber weighs more than the second most common reinforcement, carbon fiber, and is not as stiff, but is more impact-resistant and has a greater elongation-to-break (that is, it elongates to a greater degree before it breaks). Depending upon the glass type, filament diameter, coating chemistry and fiber form, a wide range of properties and performance levels can be achieved.

During glass fiber production, raw materials are melted and drawn into delicate and highly abrasive filaments, ranging in diameter from 3.5 to 24 μm. Silica sand is the primary raw ingredient, typically accounting for more than 50% of glass fiber weight. Metal oxides and other ingredients can be added to the silica and processing methods can be varied to customize the fibers for particular applications.

Glass filaments are supplied in bundles called strands. A strand is a collection of continuous glass filaments. Roving generally refers to a bundle of untwisted strands, packaged, like thread, on a large spool. Single-end roving consists of strands that made up of continuous, multiple glass filaments that run the length of the strand. Multiple-end roving contains lengthy but not entirely continuous strands, which are added or dropped in a staggered arrangement during the spooling process. Yarn is a collection of strands that are twisted together.

Different Glass Fibers in Composites

There are different kinds of glass used in composites.  Such as E-glass, S-glass, C-glass. Electrical or E-glass fiber, so named because its chemical composition makes it an excellent electrical insulator, is particularly well suited to applications in which radio-signal transparency is desired, such as aircraft radomes, antennae and printed circuit boards. However, it is also the most economical glass fiber for composites, offering sufficient strength to meet the performance requirements in many applications at a relatively low cost. It has become the standard form of fiberglass, accounting for more than 90% of all glass-fiber reinforcements. At least 50% of E-glass fibers are made up of silica oxide; the balance comprises oxides of aluminum, boron, calcium and/or other compounds, including limestone, fluorspar, boric acid and clay.

When greater strength is desired, high-strength glass, first developed for military applications in the 1960s, is an option. Known by several names — S-glass in the US, R-glass in Europe and T-glass in Japan, its strand tensile strength is approximately 700 ksi, with a tensile modulus of up to 14 Msi. S-glass has appreciably greater silica oxide, aluminum oxide and magnesium oxide content than E-glass and is 40-70% stronger than E-glass.

E-glass and S-glass lose up to half of their tensile strength as temperatures increase from ambient to 540°C, although both fiber types still exhibit generally good strength in this elevated temperature range. Manufacturers are continually tweaking S-glass formulations. A new S-3 UHM (for ultra-high modulus) Glass, for example, was introduced by AGY (Aiken, SC, US) in 2012. The new S-3 glass has a tensile modulus of 14,359 — higher than S-glass and 40% higher than E-glass — due to improved fiber manufacturing as well as proprietary additives and melt chemistry. 

Although glass fibers have relatively high chemical resistance, they can be eroded by leaching action when exposed to water. For example, an E-glass filament 10μ in diameter typically loses 0.7% of its weight when placed in hot water for 24 hours. The erosion rate, however, slows significantly becuase the leached glass forms a protective barrier on the outside of the filament; only 0.9% total weight loss occurs after seven days of exposure. To slow erosion, moisture-resistant sizings, such as silane compounds, are applied during fiber manufacturing.

Corrosion-resistant glass, known as C-glass or E-CR glass, stands up better to an acid solution than does E-glass. However, E-glass and S-glass are much more resistant to sodium carbonate solution (a base) than is C-glass. A boron-free glass fiber, with performance and price comparable to E-glass, demonstrates greater corrosion resistance in acidic environments (similar to that of E-CR glass), higher elastic modulus and better performance in high temperatures than does E-glass. In addition, taking boron out of the manufacturing process produces fewer environmental impacts, a decided advantage.

Fiber Reinforce Composites Material (3)

Woven roving is mad of E glass fiber with plain weave. It is manily used in hand lay-up and compression molding FRP production. The typical products include boats, storage tanks, large sheets and panels, furniture, etc. It is relatively thick and used for heavy reinforcement, especially in hand layup operations and tooling applications. Due to its relatively coarse weave, woven roving wets out quickly and is relatively inexpensive. Exceptionally fine woven fiberglass fabrics, however, can be produced for applications such as reinforced printed circuit boards.

Hybrid fabrics can be constructed with varying fiber types, strand compositions and fabric types. For example, high-strength strands of S-glass or small-diameter filaments may be used in the warp direction, while less-costly strands compose the fill. A hybrid also can be created by stitching woven fabric and nonwoven chopped strand mat together.

Multiaxials are nonwoven fabrics made with unidirectional fiber layers stacked in different orientations and held together by through-the-thickness stitching, knitting or a chemical binder. The proportion of yarn in any direction can be selected at will. In multiaxial fabrics, the fiber crimp associated with woven fabrics is avoided because the fibers lie on top of each other, rather than crossing over and under. This makes better use of the fibers inherent strength and creates a fabric that is more pliable than a woven fabric of similar weight. Super-heavyweight nonwovens are available (up to 200 oz/yd²) and can significantly reduce the number of plies required for a layup, making fabrication more cost-effective, especially for large industrial structures. High interest in noncrimp multiaxials has spurred considerable growth in this reinforcement category.

Fiberglass Weaving Fabric

Our Fiberglass weaving fabric including E-glass Chopped strand mat, fiberglass woven roving, fiberglass stitched mat, combo mat etc.

Fiberglass Mats are nonwoven fabrics made from fibers that are held together by a chemical binder. They come in two distinct forms: chopped and continuous strand. Chopped strand mats contain randomly distributed fibers cut to lengths that typically range from 38 mm to 63.5 mm. Continuous-strand mat is formed from swirls of continuous fiber strands. Because their fibers are randomly oriented, mats are isotropic — they possess equal strength in all directions. Chopped-strand mats provide low-cost reinforcement primarily in hand layup, continuous laminating and some closed molding applications. Inherently stronger continuous-strand mat is used primarily in compression molding, resin transfer molding and pultrusion applications and in the fabrication of preforms and stampable thermoplastics. Certain continuous-strand mats used for pultrusion and needled mats used for sheet molding eliminate the need for creel storage and chopping.

Woven fabrics are made on looms in a variety of weights, weaves and widths. Wovens are bidirectional, providing good strength in the directions of yarn or roving axial orientation (0º/90º), and they facilitate fast composite fabrication. However, the tensile strength of woven fabrics is compromised to some degree because fibers are crimped as they pass over and under one another during the weaving process. Under tensile loading, these fibers tend to straighten, causing stress within the matrix system.

Several different types of weaving are used for bidirectional fabrics. In aplain weave, each fill yarn (i.e., yarn oriented at right angles to the fabric length) alternately crosses over and under each warp yarn (the lengthwise yarn). Other weaves, such as harness, satin and basketweave, allow the yarn or roving to cross over and under multiple warp fibers (e.g., over two, under two). These weaves tend to be more drapable than plain weaves.

Fiber Reinforce Composites Material (1)

Depending on different applications, glass fibers used to reinforce composites are supplied directly by fiber manufacturers and indirectly by converters in a number of different forms.

Roving is the simplest and most common form of glass fiber. It can be chopped, woven or otherwise processed to create secondary fiber forms for composite manufacturing, such as chopped strand mats, woven fabrics, braids, knitted fabrics and hybrid fabrics. Rovings are supplied by weight, with a specified filament diameter. The term yield is commonly used to indicate the number of yards in each pound of glass fiber rovings. Similarly, tow is the basic form of carbon fiber. Typical aerospace-grade tow size ranges from 1K to 24K (K = 1,000, so 12K indicates that the tow contains 12,000 carbon filaments). PAN- and pitch-based 12K carbon fibers are available with a moderate (33-35 Msi), intermediate (40-50 Msi), high (50-70 Msi) and ultrahigh (70-140 Msi) modulus. (Modulus is the mathematical value that describes the stiffness of a material by measuring its deflection or change in length under loading.) Newer heavy-tow carbon fibers, sometimes referred to as commercial-grade fibers, with 48K-320K filament counts, are available at a lower cost than aerospace-grade fibers. They typically have a 33-35 Msi modulus and 550-ksi tensile strength and are used when fast part build-up is required, most commonly in recreational, industrial, construction and automotive markets. Heavy-tow fibers exhibit properties that can approach those of aerospace-grade fibers but can be manufactured at a lower cost because of precursor and processing differences. 

A potentially significant recent variation is carbon fiber tow that features aligned discontinuous fibers. These tows are created in special processes that either apply tension to carbon tow at differential speeds, which causes random breakage of individual filaments, or otherwise cut or separate individual carbon filaments such that the filament beginnings and ends are staggered and their relative lengths are roughly uniform so that they remain aligned and the tow maintains its integrity. The breaks permit the filaments to shift position in relation to adjacent filaments with greater independence, making the tow more formable and giving it the ability to stretch under load, with greater strength properties than chopped, random fibers. Fiber forms made from aligned discontinuous tows are more drapable; that is, they are more pliable and, therefore, conform more easily to curved tool surfaces than fiber forms made from standard tow.

Replace Steel in Bridge with GFRP

After extensive laboratory research on glass fiber reinforced polymer (GFRP) as internal reinforcement of concrete, graduate students at the University of Miami are working with Moss Construction Management to substitute steel deck reinforcement with GFRP rebars in the construction of the “Fate Bridge” on campus in an effort to combat future corrosion problems. To date, GFRP has proven to be an effective internal reinforcement for concrete structures as an alternative to steel due to its magnetic transparency, corrosion resistance, durability, high strength-to-weight-ratio, and life expectancy. GFRP is also about four times lighter than steel.

GFRP bars, replacing standard steel rebars for concrete reinforcement, have been laid out on the bridge deck. The next step is casting the concrete. This decreases the amount of labor needed to complete the same tasks in construction sites. This also makes the use of GFRP more advantageous than steel for the bridge project, and it could decrease concrete usage in the future.

Lead by their advisor, the students are installing a state of the art monitoring system with two types of gauges embedded in concrete and directly attached to the reinforcing GFRP and steel rebars in the bridge deck and superstructure. The Vibrating Wire Strain Gauges are designed to measure strains on the steel or GFRP internal reinforcement of certain concrete elements in the bridge. These gauges consist of a steel wire tensioned between two mounting blocks attached to stainless steel pads which are epoxy bonded to the rebars. The Concrete Embedment Strain Gauges are designed to measure strains directly by embedment in concrete using the vibrating principle with a steel wire compressed between two blocks.

This article is from glass fiber chopped strand mat manufacturer WB COMPOSITES

Fiberglass Is Still Material of Choice for Most Boatbuilders

1. What are the various marine manufacturing segments?

When break the industry down into three separate segments: engines, vessels and accessories. There are four different types of engines used depending on the type of vessel. Accessories include anchors, tubs and showers, which can be cultured marble or fiberglass products. The vessel, or boat segment, is where composites really fit in. The vessels could be pontoons, cruisers (a joy ride, comfortable vessel), speed boats (built for things like water skiing to 100 mph races) and yachts.

2. The trends between carbon and fiberglass composites

Right now, the majority of the industry continuing to use fiberglass over carbon composites because it offers high quality and you can get it for lower cost. However, when you look at racing boats, people will look at carbon because weight is the biggest factor. But when looking at the general boat manufacturing industry that sells to families or fishermen, the most economical solution is still fiberglass.

3. Is there one segment of the marine industry that uses composites more?

Pontoons are usually made from aluminum, and you’ll find a mix among small fishing boats, but personal watercrafts such as cruisers and yachts are primarily fiberglass. You may find two or three manufacturers who use aluminum, but by and large, composites are the material of choice.

This article is from fiberglass chopped strand mat manufacturer zccyfiberglass.com

Fibre-reinforced composite materials Introduction

Fibre-reinforced composite materials have gained popularity in high performance products that need to be light-weight yet strong enough to take harsh loading conditions such as in transport (cars and body panels, bumper, engine components, fuel lines), aerospace (bulk head and floor, landing gear door, rotor blade, satellites structure, cargo liner) . Boat decking (Boat hull, submersible pressure hull, propeller, shaft). Engineering (pipe system, power transmission drive shaft storage tank, air duct work, pressure vessel), Sports (bike frames, canoe, finishing rods, skipoles, racquets surf band). Health (Artificial teeth), Domestic purpose (shower unit, furniture, sanitary wear, bath.

The matrix materials can be introduced to the reinforcement before or after the reinforcement material is placed into the mould cavity or on the mould surface. The moulding methods can be by transfer moulding, press moulding, pultrusion moulding, vacuum bag moulding, filament winding, casting, centrifugal casting, wet lay-up, compression moulding, thermoplastic moulding, hand lay-up, spray lay-up.

The use of glass fibre to fill polyester has been reported, Polyester was reinforced with glass fibre and it was found that the increase in specimen size geometry led to an increase in energy at break, peak load, critical strain energy release rate and critical stress.

Woven roving glass fibre and chopped strand glass fibre have been utilized successfully in preparing polyester composites. The tensile strength and tensile modulus of the polyester composites were found to increase with increase in number of plies. The tensile strain of the prepared composites increased with increase in number of plies and further addition of plies decreased the tensile strain.

The use of glass fibre woven roving and chopped strand mat for the automobile industry will greatly reduce the weight which when used in fabricating the entire car body will result to a decrease in fuel consumption and increase in the speed of the car.

Material of Glass Fiber Chopped Strand Mat

The Glass used commonly for GRP is a calcium-alumina borosilicate with an alkali content of less than one per cent. It is commonly known as ‘E’ type glass, since it was originally developed for use in electrical insulation systems.

Glass Fibers are produced by running molten glass from a direct melt furnace into a platinum alloy bushing containing a large number of small holes, from each of which a glass filament is drawn. Filaments for commercial use are normally between 9 and 15 microns in diameter. The filaments are “dressed” with an emulsion before being gathered into fibres. The fibres are remarkably strong-the tensile strength being particularly high. They also exhibit good chemical and moisture resistance, have excellent electrical properties, are not subject to biological attack and are non-combustible with a melting point around 1500oC-all excellent qualities in a plastic reinforcement.

The glass fibers can be used in a variety of ways-chopped into short lengths(“chopped strands”); gathered together into loosely bound ropes (“rovings”); woven into a variety of fabrics, produced from yarn made by twisting and doubling continuous strands. In the UK, the most widely used Glass Fiber material is chopped strand mat, which consists of glass strands chopped together in short lengths (approx. 50mm) and held together in mat form by a polyvinyl acetate or polyester binder. The mat is available in a range of weights, from 225gm2 to 1200gm2, and is a useful general purpose reinforcement.

Production Machine of Fiberglass Chopped Strand Mat -Drying Oven

The drying-oven is composed by a tunnel thermally isolated and furnished with a conveyor belt.

     The drying-section is heated by the direct-gas-fired system.

     The dryer is divided in zones. Each zone has a circulating fan and separate          temperature controls.

1. Conveyor Belt

      The belt of the conveyor is a special stainless steel wire mesh, of the upper side, the mesh is supported by a series of rollers equipped with ball-bearings (outside of the oven).

      Cleaning brushes and cleaning burners are mounted on the conveyor belt.

      A belt guiding and tension system is provided. 

2. Ventilation

      Over and under the upper belt section are mounted special air-distributing cases. The upper ones are blowing and the under ones are sucking. 

      They are providing the rational distribution and the ventilation of the air all over  the surface of the fiberglass chopped strand mat. under the sucking cases are mounted air-filters of mat or of veils.

      The motion of the air in each sector is provided by heavy duty ventilators with special shovels.

      The construction of the ventilators and the air popes for the blowing and  sucking and the cases is realized in matter to make easily the cleaning operations.

3. Exhausted air

      In the sections, exhausters will provide for the exchange of the circulating air.

4.  Air-Heating

      Each section is furnished with his own gas burner. After passing the material to dry, the hot air is sucked by the lower cases and therefore returns in cycle.

      The fresh air is sucked by holes with filters, opportuned placed on the sucking pipe.

5. Control Unit of The Burning and The Temperature

       Each burner is furnished with a set of controls for the temperature regulation. 

       Each set is composed by :

Temperature regulator

The thermo states of max. and min.

The timer for the burning cycle

The control U.V, photo cells

The servo control  for the flame modulation  

      For the circulating, the exhaust and the combustion air are foreseen control units of the pressure.

      All these units will be placed into a control-panel.

6. Thermal insulation cleaning and accessibility

      The drying tunnel is composed by a strong frame of iron U-profiles, covered with insulating panels, the hole structure is dis-assemblable.

      By planning the structure we have considered the thermal expansion and             provided for the necessary. the insulating panels are manufactured with special iron sheets. 

      They are filled with glass wool.

      Along the sides of the oven, at a suitable distance, are mounted inspection          doors.

      The distribution cases are furnished with openings to make easy the cleaning        and maintenance.

Binder Applicators System For Fiberglass Chopped Strand Mat

Powder Binder

The glass fibers are transferred from the conveyor belt of the forming section to another conveyor belt for the binder application. The forming belt will remain clean and dry everytime. Binding with powder is composed by 2(two) powder-binder-applicators, and a series of sprays of demineralized (distilled) water.

Both sides of the mat, the upper and the lower-one, are lightly sprayed with distilled water, that operation is necessary or a better adhesion of the binder. The special powder-applicators warrant an optimal distributing .

Between the two applicators a vibrator is applied providing that the powder is also passing to the lower side of the mat.

Binding with Emulsion

The curtain system used warrants a perfect distribution of the binder. The excess of binder will be recovered by a special sucking system.

This system pulls the air through the fiberglass chopped strand mat and a part of the binder will be taken off. By that mater the binder will be distributed uniformly and the excess of binder eliminated. 

Obviously the binder will be re-employed after special filtering which separates the air and the dirt.

The binder is stored in containers in the mixing room and conveyed at low pressure by a pipeline to a small tank near the mat-plant.

A special device maintain the level of the tank constant. Also the recovered binder will be conveyed to the tank. A pumping system conveys the binder from that tank to the curtain distribution system.