Odd pairings are legendary. There’s Bill and Hillary. Jimmy Carter and his beer-drinking brother, Billy. And then there was Andrew Wyeth and his brother, Nat. One was an artist famed for his depictions of the parched winter landscapes of Maine and Chadds Ford. The other was responsible for much of the litter that mars those landscapes—and most others, as well.
Nathaniel Wyeth, an engineer who spent his career with DuPont, invented the plastic soda bottle. That’s the bottle—patented in 1973—whose manufacture requires 1.5 million barrels of oil annually and has only a one-in-five chance of ever being recycled.
During his career, Wyeth invented or was the co-inventor of 25 products and processes in plastics, textile fibers, electronics and mechanical systems. In 1986, he was elected to the Plastics Hall of Fame. He also was a fellow of the American Society of Mechanical Engineers.
“Very seldom do [ideas] come out of nowhere,” Wyeth told Kenneth A. Brown, author of Inventors at Work, in the 1980s. “It’s usually a culmination of one thought after another that leads to a solution and a complete understanding of the problem.”
“Complete” in his eyes, perhaps.
The third child of Carolyn and Newell Convers (N.C.) Wyeth, Nathaniel was initially named for his father. But the boy’s parents went to court before he reached age 5 and had his name legally changed.
It was their habit to put toddler Nat out on a sunny, enclosed porch in a baby carriage for his daily nap. But his hands were always greasy when they got him up. “One day, they kept an eye on me,” Wyeth said later. “Then, they noticed me lean over the side of the coach, reach down and move the wheels with my hands.”
By turning the wheels, the little boy made the coach move from one end of the porch to the other. Back and forth, over and over, and dirtying his hands in the process.
“I don’t know why we should encumber this boy with an artist’s name when he’s undoubtedly going to be an engineer,” said his father. “Look at his understanding of those wheels and the way he’s moving that coach!”
So, Newell Convers Wyeth Jr. became Nathaniel Convers Wyeth, a name he shared with an uncle who was an engineer.
Throughout his life, Wyeth dismissed the notion—posed repeatedly—that his father might have been disappointed that he didn’t paint. “The only thing he insisted on was that whatever we did, we should do it with all our hearts, with all our might,” he said.
And he did. As a boy, Wyeth cannibalized “I don’t know how many” alarm clocks for parts to build model speedboats. He used an airplane propeller to drive a pontoon boat. And he built a “sea sled”—6 feet long, with a curved bow and an outboard motor—so fast the Wyeths dubbed it Ex-Lax. When the Wyeths sailed to Monhegan Island during their Maine summers, Nat went along in Ex-Lax, doing circles around the family’s larger, slower powerboat. “The local paper,” said Wyeth, “wrote that I had taken Ex-Lax and gone to Monhegan,” a description which confused or offended some readers. “It sounded terrible.”
Later, Nat expanded on the curved-bow idea to build a 20-foot hydroplane. N.C. Wyeth provided a Ford V8 engine and, when the craft was launched, the artist personally waded into the frigid Maine waters to christen his son’s Silver Foil with champagne. “He was so excited that he forgot to take his watch out,” said Wyeth, “and it just got soaked.”
Silver Foil reached 45-50 miles per hour, but never had quite enough power to plane—that is, to lift out of the water. “It had a manual transmission, and we just couldn’t shift it fast enough,” said Wyeth.
Wyeth earned bachelor’s and master’s degrees in mechanical engineering from Penn, a school recommended by another engineer-uncle, Stimson Wyeth. After college, he joined Delco, a Dayton, Ohio, auto-parts company recommended by his namesake, Uncle Nathaniel.
At Delco, Wyeth made a good impression early on by solving a production problem in the manufacture of Sani-Flush, the toilet bowl cleaner. One of the ingredients kept plugging a valve in a machine that mixed the cleaner. The valve—essentially a gate or door—crossed from one side of a pipe to the other, but sometimes couldn’t close entirely because the gritty, acidic material was in the way.
Wyeth replaced the single-gate valve with a two-door version. The two doors met in the middle of the pipe where the material was moving fastest and less likely to clog. That got Wyeth a promotion to Delco’s R&D lab to work on new concepts and devices. It was exactly where he wanted to be—but at DuPont, near his home, not in Ohio. So, in 1936, as soon as an opportunity arose, Wyeth jumped ship.
At DuPont, Wyeth’s first invention was a machine that filled cardboard tubes with gunpowder to make dynamite. Previously, the process involved a lot of manual labor, requiring that employees be exposed to nitroglycerin, which dilates blood vessels (its medical purpose) and creates painful headaches. DuPont wanted to minimize this exposure.
Wyeth built a prototype that impressed his boss, who in turn showed it to the explosives supervisor. The higher-ups then authorized construction of a final version.
“That was music to my ears,” said Wyeth. “To see an idea finally go into motion is one of the most gratifying ex-periences I think anyone can have.”
The plastic soda bottle was purely Wyeth’s idea. Informed that plastic couldn’t withstand the pressure of carbonation, Wyeth wanted to see for himself. He went home, filled an empty detergent bottle with ginger ale and put it in the refrigerator overnight. The next morning, the bottle was so swollen that it had become trapped. Wyeth couldn’t remove it until he had carefully bled off some of the built-up pressure.
“No wonder they don’t put carbonated beverages in plastic bottles,” he realized. “They’re too weak.”
Wyeth knew that plastic could be strong. Previously, he’d been involved in the development of Typar—a polypropylene sheeting material used as backing for rugs—for building wrap, to cover muddy areas before pouring concrete, and as landscape fabric to suppress weeds. From his experience working with nylon, Wyeth knew that the strength of plastic increases when it is stretched. When making nylon thread, for instance, stretching causes the molecules in the material to line up. But unlike thread, which needs to be strong in only one direction, plastic bottles needed to be strong biaxially. That is, from top to bottom and from side to side.
Wyeth solved the problem with what he called a “preform” mold, which looked like a test tube with screw threads on the inside. Rather than running in a single spiral, however, the mold had two sets that crossed each other in a diamond crisscross pattern. When the plastic was extruded through this mold, its molecules aligned in the biaxial fashion that Wyeth intended. “It took a lot of experimentation,” he said.
Working with one assistant and a hand press, Wyeth produced many shapeless globs of plastic and, later, some truly ugly containers. “I remember bringing some of those samples over to my boss,” recalled Wyeth. “He’d ask, ‘Is this all you’ve done for $50,000?’”
Wyeth later estimated that he had made 10,000 attempts. Success came late in the day, when the lab was dimly lit. He and his assistant opened the mold, expecting more shapeless globs of resin. Instead, the mold seemed to be empty. They looked closer, and found a crystal-clear bottle. “Since then, I’ve seen countless truly beautiful PET bottles,” said Wyeth. “But none of them will ever be as memorable as the first.”
That first bottle was polypropylene. Then, as his final improvement, Wyeth replaced polypropylene with PET, which has superior elastic properties but is permeable to carbon dioxide over time. Put a Coke on the shelf for six months, and it will go flat. That never happened when soda was bottled in glass. It’s why soft drinks now have expiration dates.
By 1980, production of plastic beverage bottles had exploded to 2.5 billion containers—and by 1985, to 5.5 billion units. Glass became obsolete. Plastics experts predict that the PET bottle will eventually be standard for wine, liquor, beer and many other products. (And, of course, for roadsides.)
Years earlier, defending his son’s career choice, N.C. Wyeth had insisted, “An engineer is just as much an artist as a painter.”
But the elder Wyeth—famously critical of his own work—also knew that not all art is good.
E-mail comments to Mark E. Dixon at firstname.lastname@example.org.
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