The Fiberglass Story
j.r. eyerman/time life pictures/getty images2007_4_8 Anyone who has melted and stretched a glass rod in chemistry class has made fiberglass. That’s how the ancient Phoenicians, Egyptians, and Greeks did it; archeologists have found artifacts from all these civilizations laced with decorative glass filaments. In medieval Venice, artisans used finer and finer threads to adorn their glassware. As the filaments grew thinner, they became more flexible, though they were still thick enough to break if bent sharply.
With the arrival of the Industrial Revolution, glass fibers started being used for more than ornamentation. In 1836 a Frenchman named Ignace Dubus-Bonnel received the world’s first patent on a method of making them. In 1872 the Franklin Institute, in Philadelphia, reported that an engineer named Coleman Sellers had produced “mineral cotton” by blowing a jet of steam through liquid glass. The result was a white mass that could be used for insulating steam boilers and pipes.
As early as 1842 a British silk weaver made a dress from glass fibers, and in 1879 a newspaper reported that a Viennese glass artisan had opened a shop in Germany where he sold fashionable apparel he had made from spun glass: “cuffs, collars, veils … white, curly glass muffs, … and ladies’ hats of softest glass feathers.” A year later a German glass blower made an iridescent cloth by weaving silk fibers in one direction and glass fibers in the other. In 1893 Edward D. Libbey, of the Libbey Glass Company, exhibited a dress made of that cloth at the Chicago world’s fair. The garment left a good deal to be desired: It weighed 131/2 pounds, and the glass fibers tended to break when folded.
Clothing aside, glass fibers seemed promising for a variety of uses, but there were two main problems: It was hard to make them thin enough to be completely flexible, and no reliable method of mass production existed. These obstacles were overcome in the 1930s after researchers at the Owens-Illinois Glass Company, in Alton, Illinois, made a pair of accidental discoveries.
Owens-Illinois had a long record of innovation. Its founder, Michael Owens, developed a series of successful glass-blowing machines in the 1890s and early 1900s. During the Depression, company executives seeking new markets for glass hired an engineer named R. Games Slayter to come up with ideas.
The first step toward fiberglass came as Slayter was experimenting with ways of fusing a colored trademark onto a bottle. When he fed powdered glass into a flame, the unintended result was a heap of cottonlike fibers. He and his staff adapted the process to make glass-fiber air filters for ventilating equipment. They removed dust much more efficiently than cotton, the usual material, and were cheap enough to be thrown away when they became clogged. Owens-Illinois filters went on the market in early 1932 and were a steady seller for decades, particularly with the spread of air conditioning.
This was the first commercially successful product made from glass fibers, but the process still had limited utility. It yielded a tangled mass of short, coarse fibers, while many envisioned uses demanded long, thin single fibers. The most important advance in making the modern glass-fiber industry possible came in 1932. Dale Kleist, a graduate student at Ohio State University, was working part-time at Owens-Illinois as a researcher. Slayter wanted the company to make glass blocks for architectural use, and Kleist, under the direction of Jack Thomas, was looking for a way to seal the two halves of a block together so that moisture couldn’t get inside.
He decided to try a metal-spraying gun, the kind used to melt bronze and blow it onto baby shoes. He filled the gun with molten glass instead of bronze and discovered that it created a shower of ultrafine, threadlike glass fibers. Thomas and Slayter immediately recognized that this was an excellent way to make glass wool for insulation and that it might be adaptable for other glass-fiber applications.
Four years later Slayter and his small R&D staff were turning out individual strands long and flexible enough to be woven into cloth. The cloth was remarkably strong, and it could be cut and folded just like ordinary fabrics.
As it happened, Corning Glass, in upstate New York, had also been experimenting with producing glass fibers for insulation, and in 1935 the company suggested to Owens-Illinois that they work together. They did, and the joint venture led to the creation of an independent firm, the Owens-Corning Fiberglas Corporation, in 1938. (Fiberglas was the company’s name for its glass fibers; soon the term, with its spelling corrected, came to be used generically.) Corning supplied most of the basic research, while Owens-Illinois contributed most of the manufacturing know-how. Owens-Corning set up its first manufacturing plant in Newark, Ohio, near the home office in Toledo.
library of congress2007_4_10 Owens-Corning spent millions of dollars learning how to manufacture fiberglass in commercial quantities. The basic procedure, still in use today, begins with marbles of raw glass. Using marbles has two purposes: First, they can be added to the melt at a controlled rate, which helps keep the temperature inside the reservoir of melted glass constant; and second, transparent marbles can easily be inspected for impurities.
The glass is melted in an electric furnace and then forced through a perforated metal plate called a “bushing.” The bushing is made of platinum or another exotic metal, because molten glass is so highly abrasive that most metals would be unable to resist it. Platinum’s high melting point—3,200 degrees Fahrenheit—allows it to be heated to the temperatures needed to let glass, which melts between 1,800 and 3,800 degrees, flow through.
To form continuous filaments, the molten glass, after flowing through the tiny holes in the bushing, is attached to a winder and pulled until it reaches a diameter between 27 and 180 millionths of an inch (the smaller figure is about 1/100 the width of a human hair). Hundreds of parallel filaments are gathered on a large steel drum, where they are combined into a fine, untwisted strand called a “sliver” (pronounced sly-ver). The sliver is fed onto a spool, and from there it can be put through conventional textile processes, such as twisting or plying, and woven into cloth. The strands can also be fed into another machine to make a heavy yarn or loose rope called a “roving.”
A different process is employed to make short, noncontinuous strands. It uses a bushing with wider holes, which the molten glass passes through by gravity. As the strands emerge, high-pressure steam or compressed air is blown on them (Owens-Corning consulted the rocket pioneer Robert Goddard on the original design of the steam nozzles), yielding an explosion of tiny glass strands 8 to 15 inches long and about 220 millionths of an inch thick. They drop down to a conveyor belt and are collected for use in batts, rolls, or blankets.
In many ways, fiberglass acts like regular glass. It repels moisture; most acids and alkalis don’t penetrate the filaments; it resists mold and mildew; it doesn’t conduct electricity; and it doesn’t decay, rust, shrink, expand, or burn.
By 1940 Owens-Corning had managed to produce a glass-wool insulation that was less expensive than mineral wool (or rock wool), the most popular insulating material of the time, which is made by blowing steam through molten stone. The company’s research advances coincided with the approach of World War II. In 1939 the U.S. Navy specified fiberglass as the preferred thermal insulation for all new warships.
Yet even greater things were in store. Slayter and his team had also discovered that fiberglass embedded in various hardening resins could form a rigid, tough, lightweight, easily molded material that could replace plywood and sheet metal. In somewhat confusing fashion, this material is also commonly called fiberglass, though it is more accurately known as fiberglass-reinforced plastic, or FRP. Tests showed that the tensile strength of FRP, whether reinforced with woven cloth, mat (compressed short fibers), or rovings, was greater than that of most metals.
In June 1941 Owens-Corning opened a second plant, this one in Ashton, Rhode Island, devoted exclusively to FRP for military uses. The company developed a lightweight, FRP-encased wooden board to replace aluminum for the interior paneling of ships. This freed up aluminum for other uses, notably in aircraft. And while the technology of molding the substitute into complex shapes was far from ready for mass production, a few military airplanes were made with experimental FRP components.
A helpful advance in FRP molding came in 1943, when American Cyanamid introduced a polyester formulation called Laminac, a two-part resin that used a hardener and an accelerator and was cured at room temperature. This and other polyester resins made the FRP lamination process faster and easier, since high temperatures and pressures were not required, although both resin and fibers remained expensive. By 1945 the fiberglass industry was producing 3.5 million pounds of FRP a year, all of it for military use, most notably the “radomes” that protected radar equipment but let the radar beams pass through unaffected.
library of congress2007_4_11 After the war virtually every industry in North America rushed to find uses for fiberglass. One of the earliest and most successful was the FRP fishing rod. Another was pleasure boats. From time immemorial most pleasure craft had been made of wood. And from time immemorial their hulls had tended to warp, leak, shed paint, and attract worms, bacteria, fungi, and barnacles. Making boats out of FRP eliminated all these problems.
According to Daniel Spurr’s excellent book Heart of Glass , the fiberglass-boat industry originated with a Midwestern tinkerer named Ray Greene. The son of a chemist, with graduate degrees from Ohio State in industrial and mechanical engineering, Greene had put himself through college by building and selling small wooden sailboats. But his dream was to build a pleasure craft from plastic.
In 1937 he began experimenting with scale-model hulls made of melamine and urea formaldehyde plastic resins. Since these were brittle, he tried to reinforce them with materials ranging from canvas fabric to wire window screening. When Owens-Corning began releasing fiberglass cloth for nonmilitary use in 1941, Greene managed to buy half the initial run.
He made a new batch of model boats reinforced with fiberglass. The experiments proved so encouraging that he decided to build a full-sized hull. The challenge was to make an autoclave big enough to heat-cure a small dinghy. He pieced one together from junkyard parts but never had to use it because the next year, 1942, he heard about American Cyanamid’s new cold-curing polyester resin. Despite wartime restrictions, he managed to get hold of about a gallon.
Greene soaked fiberglass cloth in the resin and used it successfully to make a small, seamless hull. A number of other boatbuilders did the same thing. There wasn’t much information circulating at the time, so each person or firm worked independently, experimenting by trial and error. One typical mistake occurred at a small company in the Bronx that the Navy commissioned to make an FRP dinghy for coastal use. The craftsmen fashioned a wooden mold, laid in the resin-soaked glass cloth, and let it cure. After the resin had hardened, they discovered that the hull wouldn’t separate from the mold. No one knew that the process needed a release agent. The dinghy became one big lump of solidified resin, stuck irretrievably to its mold. The workers gave up and eventually tossed the whole mess into the Harlem River.
Meanwhile, with civilian automobile production shut down for the duration, carmakers also looked forward to the post-war use of FRP. One of its earliest proponents was a farsighted engineer named William B. Stout, of Dearborn, Michigan. He had built his first aerodynamic, rear-engine Stout Scarab car in 1932. With its roomy interior, movable seats, folding table, and six-foot sofa, the Scarab was more like a contemporary minivan than a car. Stout improved the Scarab in 1935, giving it 55 square feet of floor space, twice that of the typical 1935 car.
The FRP-bodied Scarab began in April 1944 with a meeting between Stout and Slayter. Stout suggested that he and Owens-Corning build a “plastic car.” The resulting Scarab was perhaps the earliest automobile to have an all-fiberglass body. Even the chassis was made of FRP. The only metal components were the door hinges, latches, lamp bezels, engine mounts, and suspension parts.
The Scarab body consisted of 13 large FRP pieces. The most important and heaviest was the fiberglass floor pan/chassis. Everything else was bonded to it: cowl, rear bulkhead, side panels, roof, and wraparound bumpers. As in his previous Scarabs, Stout placed a Ford or Mercury V-8 engine in the rear. The steel motor mounts were also bonded in place.
The 1945 Scarab’s interior needed no central transmission tunnel, so the floor was perfectly flat. The front seats were bonded in place; in the back, Stout put a movable sofa, a small table, and easy chairs. Because of overengineering, the FRP Scarab weighed roughly what it would had it been made of aluminum. Owens-Corning said that the total cost of materials was only $76, though fabrication had cost an estimated $100,000.
The car was finished on February 25, 1945, and after the war Stout drove it coast to coast several times for publicity and test purposes. He then used it for personal family transportation until 1951, putting more than 100,000 miles on it. Today you can see it at the Detroit Historical Museum.
Soon after the Scarab’s debut, West Coast entrepreneurs began making FRP automobile bodies. One was Howard A. (“Dutch”) Darrin, a well-known coachbuilder. Between 1938 and 1942 he designed and customized Packards and went on to design several postwar Kaiser and Frazer models, including the FRP-bodied 1954 Kaiser-Darrin roadster.
During the war Darrin designed a streamlined sport roadster. He took the blueprints to a Southern California plastics company and asked if they could build a body for the roadster out of FRP. Brandt Goldsworthy, the aeronautics engineer who owned the company, had by then fabricated some 300 FRP boats. He said yes, and in 1946 he did it.
Dutch Darrin’s roadster was probably the world’s second FRP-bodied car. He had hoped to produce it in quantity, but when that didn’t work out, he revised the styling slightly and applied it to the 1947 Kaisers and Frazers, which were also initially meant to have FRP bodies. The problem with FRP, though, then as now, was that manufacturing methods were too slow for mass production of car bodies. To understand why, look at the stages of molding a part from FRP.
There are several ways to form a car body out of fiberglass, but every one of them involves a great deal of handwork. After being saturated with a binder—generally a viscous liquid, something like warm honey—the fiberglass cloth must be shaped over its molds or stamped between them and allowed to cure, sometimes under pressure supplied by a huge inflatable bladder. However it’s done, it takes a great deal more time and effort than the usual run of metal stamping. Nevertheless, fiberglass car bodies have had passionate proponents for six decades now.
Bill Tritt typified the fiberglass entrepreneurs of the postwar era. Born in Pasadena, California, in 1917, he began making fiberglass masts for sailboats in 1946. A year later he was using FRP to build entire boat hulls. The 21-foot Green Dolphin sloop and the popular Dincat, Dinkitten, and Glasscat were early products of Glasspar, his Santa Ana company.
Tritt, who retired in 1980 and currently lives in West Virginia, recalled that Glasspar was building mainly boats when, in 1949, an Army major named Ken Brooks asked him to mold a lightweight FRP roadster body for his home-built sports car (basically a war-surplus jeep, which his wife had found too ugly to drive in its unadorned state). Tritt molded the body over the course of eight months, and the assembled vehicle, with its one-piece pale green exterior, came to be called the Brooks Boxer. To prove the body’s durability, Tritt took it on a long test drive before turning it over to Major Brooks.
The Boxer and three other custom-bodied fiberglass roadsters were shown at the 1951 Los Angeles Motorama, a car show promoted by the publisher of Motor Trend and Hot Rod magazines. Public reaction was positive enough to encourage Glasspar to make and sell FRP body kits. Soon backyard sports-car fabricators began buying these kits and assembling their own roadsters, in a sort of Boxer Rebellion against Detroit conformity. Tritt’s kit cars, which showed a glimmer of the Jaguar XK 120’s styling, were dubbed the Glasspar G2.
Unfortunately, the supply of polyester resin essentially stopped as the Korean War dragged on. Most FRP again went toward military uses, and Glasspar’s business came to a halt. Then, by a fluke, Tritt heard about Naugatuck Chemical, a company owned by U.S. Rubber that was shipping barrels of polyester resin from its Connecticut headquarters to a warehouse south of Los Angeles. Tritt borrowed the Brooks Boxer and drove up to the Naugatuck warehouse.
courtesy of owens-corning2007_4_12 He tried to talk the office manager into selling him a barrel or two of resin. The manager said he’d like to, but without government permission, he couldn’t. He then walked Tritt out to the parking lot, and when he saw the Boxer, his eyes widened. “What’s that?” he asked.
“A new fiberglass-bodied car,” Tritt said.
The office manager immediately phoned Connecticut and described the Boxer to Naugatuck’s president, Earl Ebers. The next day Ebers flew out to Southern California. As a chemist and auto enthusiast, Ebers was impressed by Tritt’s work and promptly had several barrels of polyester resin air-freighted to the Glasspar shops.
Production of Tritt’s sports-car body kits resumed, and Naugatuck bought two assembled Glasspar G2 roadsters, both fitted out with the company’s patented Naugahyde upholstery, to demonstrate at a 1952 plastics trade show in Philadelphia. Ebers named these cars the Alembic I and II, after an old-fashioned piece of chemical apparatus. Their fiberglass bodies caused quite a stir on the East Coast and led to articles in Life , The New York Times , and The Wall Street Journal .
Ebers took the Alembic II around to Detroit’s automakers, explaining and extolling the virtues of FRP. Owens-Corning had already talked with Kaiser, Hudson, Chrysler, and General Motors about fiberglass, and the Alembic II served as an example of what could be done. GM, too, had been experimenting with FRP since 1949. In late 1951 the company built an entire body for a 1952 Chevrolet convertible out of reinforced fiberglass. This car was taken to GM’s proving ground in Milford, Michigan. During a high-speed test run the FRP Chevy convertible rolled over. GM’s engineers were amazed at the lack of damage to the fiberglass body and the ease with which it could be repaired.
As a result, GM started making most of its concept-car bodies out of FRP. One of the best received was the Corvette. The first Corvette concept roadster went on display in January 1953 as part of GM’s touring Motorama exhibits. The response prompted GM to begin production of the Corvette.
The early ones, assembled in Flint, Michigan, used bodies made by the Molded Fiber Glass Company in Ashtabula, Ohio. Three hundred were assembled in late 1953, making it the first car from a major manufacturer with an FRP body. GM was careful to emphasize the term fiberglass , since plastics carried an image of cheapness. A GM executive told a business reporter that he didn’t mind if his company made a fiberglass body, “just so long as they don’t try to do it with any damned plastic.”
Although the Corvette was welcomed enthusiastically and remains a legend, it did not start an industry stampede toward FRP bodies. The labor-intensive production requirements still imposed a heavy penalty. Yet the Corvette did at least demonstrate that FRP could work as a niche material. In 1953 Detroit carmakers estimated that the cost to tool up an all-new sheet-metal automobile body was $5 million. The cost to tool the 1953 Corvette’s fiberglass body came to only $500,000. So for short production runs, fiberglass seemed ideal.
The 1953 Corvette body was made of 62 separate pieces. Most pieces were laid up in matched male and female metal molds, a slow and expensive process. Nor were the results all that good. Early Corvettes leaked and had wavy outer skins, and the fiberglass tended to craze and crack along the seams. In the Corvette’s favor was the weight savings. The entire body weighed only 357 pounds, roughly a third of what it would have been in steel. It couldn’t rust and didn’t dent; in fact, FRP had 13 times the impact resistance of sheet steel. If it was hit hard enough, the resulting rips and tears could be repaired fairly quickly and easily.
Early Corvettes sold slowly, and the model didn’t turn a profit until 1958. In 1962 the Molded Fiber Glass Company began making bodies for the Studebaker Avanti as well as the Corvette. Both these cars used FRP bodies mounted on conventional steel frames; the first production car with an all-fiberglass unibody (chassis and all) was the 1957 Lotus Elite, an English sports coupe that weighed just 1,455 pounds. Lotus produced about a thousand of these pretty little cars between 1957 and 1962.
Citroën made sedans with FRP roofs from the mid-1950s through the mid-1970s, Chevrolet used FRP for pickup beds (still a common use), early Thunderbirds had FRP convertible hardtops, and the “wooden” trim strips on most station wagons were actually fiberglass. So were deck lids, hoods, inner fenders, headliners, ducts, instrument panels, and seat shells, as well as the reinforcing plies of early radial tires.
Modern vehicles use FRP for such items as interior insulation, seat frames, timing-belt and instrument-panel reinforcements, air dams, spoilers, fan shrouds, leaf springs, fender liners, mufflers, and accessory running boards for pickup trucks and SUVs.
Many 18-wheelers have FRP cabs. The entire bodies of most recreational vehicles are made from FRP, while relatively low-volume sports cars, like the Chevrolet Corvette, Cadillac XLR, Dodge Viper, and Lotus Elise, have fiberglass composite body panels.
The military Humvee comes with bullet-resistant fiberglass floor panels and seatbacks. GM’s Hummer H2 uses a fiberglass hood. FRP is also used for the Chevrolet Avalanche’s midgate. The Mercedes Sprinter van boasts fiberglass suspension components to reduce unsprung weight, and the Volkswagen T5 Transporter has a fiberglass roof.
Boats and cars are far from FRP’s only uses. As far back as the late 1920s Buckminster Fuller conceived of his Dymaxion House, among whose many visionary features was a one-piece molded shower stall and tub. At the time, the technology didn’t exist for such an innovation, but today preformed FRP shower/tubs are common, as are tens of thousands of other fiberglass items. Some are big, like in-ground swimming pools and filling-station gasoline tanks. Building facades are often made of concrete sheets reinforced with fiberglass. In 1975 the 10-acre Silverdome stadium in Pontiac, Michigan, became one of the largest structures ever covered by a fiberglass roof. (It collapsed in 1985 under a snow load and was replaced with a roof made of canvas reinforced with steel girders.)
On a slightly smaller scale, the Finnish architect Matti Suuronen designed and built a series of ovaloid, flying-saucer-like houses out of FRP in the late 1960s. He called them Futuro. Suuronen’s houses were comfortably large but light enough to be carried to remote sites by helicopter. As early as 1961 the British architect Peter Falconer specified fiberglass to rebuild the old timber spire for St. Paul’s Church in Smethwick, England. In this country, American Structural Composites, Inc., supplies large, interlocking fiberglass sheets for use in constructing modular houses. A company in Pakistan makes 12-by-12-foot FRP houses, complete with kitchen and bath, for earthquake victims.
FRP has been used for some time in the manufacture of things like 18-wheeler truck cabs, motor-home bodies, seats in trains and subways, cases for rocket engines, rotor blades for helicopters and windmills, and many components for aircraft, both civilian and military. It is an important material for modernist furniture, such as Eames chairs, because of its adaptability to flowing shapes. With fiberglass, if you can model it, you can build it. And, of course, it is widely used in recreational equipment: golf clubs, tennis rackets, surfboards, water skis, snow skis, snowmobile bodies.
Costs of FRP materials have dropped steadily through the years, while the price of metals has generally trended upward. Also, manufacturing processes have gotten faster, and FRP products become more affordable year by year.
In the past, most items made of FRP had to be painted. Otherwise they tended to be translucent; you could often see the fiberglass reinforcements inside. Today fabricators can spray a gel coat onto the mold surface before laying up the glass mats and resin. Another innovation is “pultrusion,” in which glass-fiber strands are drawn through vats of resin, then pulled through a heated die. Pultrusion is great for forming reinforced rods, like golf-club shafts, fishing rods, or any product with a constant cross section—an I-beam, for example.
Strands can also be coated with powdered resin and pressed into the desired shape, eliminating the need for liquid resin. Finally, there’s filament winding, a method for making pieces with a hollow tube cross section, such as pipes, storage tanks, and open cylinders. In this process, long filaments of fiberglass are fed through a resin bath and then wound on a metal tube. When the resin has cured, the result is a tough, durable cylinder. This method can be automated with different winding patterns to give maximum directional strength.
Due to their relatively slow production processes, most applications of FRP composites are restricted to fairly low-volume uses. But fiberglass wool, which got everything started, remains a staple of the industry. By 1960 virtually all commercial airplanes were thermally and acoustically insulated with fiberglass batting. So were early missiles, like the Thor launch rocket and the Atlas re-entry vehicle. Back on earth, the largest user of fiberglass products, starting with the post–World War II housing boom, has been the construction industry. Rolls of insulation between the outer and inner walls of new buildings are a familiar sight. Less conspicuous but equally important are the fiberglass mats that go into composition roofing materials, improving the tiles’ strength and longevity.
In recent years FRP has been replaced by what we’ve come to call “composites.” That term covers a wide variety of materials, including glass fibers commingled with plastic fibers, carbon fibers, nanofibers, and other exotic, emerging technologies. Dr. Ernest Coleman, a Pennsylvania materials consultant, envisions many new uses for composites, including the possibility of glass fibers as conductors of electricity and perhaps even heat.
Meanwhile, the affordability of fiberglass in building insulation, roofing, and filtration will continue to make it a mainstay for many years to come. There’s nothing on the horizon that could replace classic fiberglass in those roles.
