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Carbon Fiber Conundrum

Published September 3, 2010

BY DOUG MCCLELLAN

Everyone in the industry can tick off reasons why bicycles benefit the environment. But one item won’t be on the list: the ability to recycle carbon fiber frames.

Carbon fiber, the stuff that makes grown cyclists swoon as they reach for their wallets, is virtually indestructible in a landfill. And while several companies claim to have developed technologies to recycle carbon fiber, no one knows when or where those technologies will become commercially available in the United States.

“We are in our infancy. The whole composites industry has for a lot of years been struggling with how do we do this? How do we recycle?” said Jim Colegrave, the father of Trek’s OCLV carbon fiber factory.

A VERY LOFTY GOAL
No American bicycle company has a bigger interest in carbon fiber recycling than Trek. Trek’s Wisconsin OCLV factory is the only large-scale U.S. carbon fiber frame manufacturer. Most carbon fiber frames are imported from China.

“We’d love to be able to say, like the auto industry, that we are trying to be diligent and are doing cradle-to-grave: We build it and when you’re ready to get rid of your bicycle, we can take it and recycle it,” Colegrove said. “Obviously, that’s a very lofty goal.”

Trek has invested heavily to cut the amount of carbon fiber waste it produces, but it still must send what’s left to the local landfill—just like a cyclist whose carbon fiber bike has come to the end of the road.

Shouldn’t Trek engineers be able to figure something out? The reality is that Trek and other companies are no more than a bruise on the banana gripped by the 800-pound gorilla dominating the world of carbon fiber: aerospace.

“We’re a big user of composites within the sporting goods industry in the U.S.,” said Chad Manuell, who oversees Trek’s carbon fiber production in the U.S. and overseas. “But when you start stacking us up against Boeing or Airbus, the recyclers that we’ve found so far seem to be catering to them or dedicated to figuring out how to get rid of their waste.”

IT CAME FROM AEROSPACE
Fortunately for Trek, and other makers and consumers of carbon fiber bicycles, the aerospace industry is looking for answers. And whatever recycling technology the aerospace industry develops for passenger and military jets may also work for bicycles and other types of sporting goods, experts said.

For airplane makers, the stakes are huge. Bicycle manufacturers get excited when they can crank out a carbon road frame that weighs less than two pounds. Yet Boeing’s new flagship passenger jet, the 787 Dreamliner, flies on 40,000 pounds of salvageable carbon fiber, according to High-Performance Composites magazine. The Airbus A380 jumbo jet uses some 55,000 pounds of composites per plane. That’s a lot of bicycle frames.

The companies that make parts for the 787 produce tons of waste. But the biggest demand for recycling will come in 30 to 40 years, when Boeing and Airbus begin to retire the 787s and A380s.

Boeing, Airbus and other aerospace companies recently created the Aircraft Fleet Recycling Association to study ways of recycling the many components used in planes.

CARBON COPIES
Airplane makers have another reason to embrace carbon fiber recycling: The stuff is expensive to produce. Carbon fiber composites are made of thin strands of fiber, many times thinner than human hair. The fibers are woven into threads to make a fabric.

The fabric is impregnated with resins, or epoxys, that harden after the material is molded into the desired shape.

Recycling carbon fiber pieces requires removing the resins until just the original fibers remain.

“Making carbon fiber is very energy-intensive,” said Ronald Allred of Adherent Technologies, which hopes to commercialize a carbon fiber recycling process. “So if you can get the fibers back in recycled form with near virgin properties, there are lots of applications for that.”

According to Boeing, it takes between 25 and 75 kilowatt-hours of electricity to make a pound of carbon fiber. A typical American residence uses about 30 kWh of power a day, according to the U.S. Energy Information administration.

(A pound of carbon fiber doesn’t translate into a pound on a high-end bicycle frame. Most of the frame’s weight comes from the resins that hold the slender fibers in place.)

“Recycling carbon fiber can be done at approximately 70 percent of the cost and using less than 5 percent of the electricity required to make new carbon fiber,” a Boeing report noted.

“If the 2 million pounds of carbon fiber scrap that commercial jet manufacturing is estimated to generate in 2014 is recovered, recycled, and substituted for virgin fiber in manufacturing applications, it will save enough electricity to power 175,000 typical homes a year.”

FEEDING JUMBO
One thing holding back recyclers is that the overall amount of carbon fiber available for recycling is relatively small, said Allred, who founded Adherent 20 years ago in Albuquerque, New Mexico.

While a tire recycler in Albuquerque processes some 150 tons of shredded rubber a day, Allred said, “with composite recycling, we’re looking at three to five tons per day. It’s way smaller.”

Adherent is seeking about $3 million in capital to build a carbon fiber recycling plant based on its technology. The centerpiece of Adherent’s process is an odd-looking structure that sits on blue steel posts outside its offices.

It’s a two-story dome covered with a thick gray insulating material and looks a little sinister, like a pint-sized nuclear reactor. “We call it the Jumbo, after Dumbo, because of the gray jacket,” Allred said.

Jumbo mixes scraps of composites with a heat transfer fluid and a catalyst and then subjects the stuff to increasing temperatures and pressures. “Essentially, it attacks the epoxy or whatever resin it is and breaks it apart,” Allred said.

Adherent claims the end product is near-virgin quality, within 5 to 7 percent of virgin carbon fiber.

A GIANT PIZZA OVEN
Far from Jumbo sits what may be the only carbon fiber recycling plant that currently accepts commercial waste.

Built in the Midlands region of the United Kingdom, the plant is owned by Recycled Carbon Fibre, Ltd. (RCF). The company plans to build a recycling plant in the United States within the next 12 months, said Martin Spooner, sales and business development manager.

RCF uses a process known as pyrolysis, which subjects carbon fiber waste to extremely high temperatures, effectively burning the resins off the fibers.

“We’re effectively putting it through a 120-foot long pizza oven,” Spooner said. The oven uses eight temperature zones as well as afterburners that cook the gasses at 1,000 degrees Fahrenheit.

RCF receives most of its waste from aerospace companies and from England’s Formula 1 industry.

Spooner said RCF’s “pizza oven” has processed dozens of bicycle frames. The company’s experience with the frames underscores some logistical hurdles.

A well-known bicycle manufacturer, whom he declined to name, has shipped several crates of “seconds” to RCF—carbon fiber frames that failed quality standards.

“The problem is, when you get a crate of bicycle frames, there’s actually not too much carbon there. There’s a lot of fresh air in that crate,” Spooner said.

But there’s an even bigger problem, he added. “Beautiful as they are, bike frames have various bits of metal all over the place. We end up having to chop off a lot of metal.”

For future shipments, the manufacturer has agreed to process the frames first. “They’re cutting off all the tubing, so we’re just getting the carbon,” Spooner said. “That means it comes to us four times as efficiently in the packaging.”

WAITING TOO LONG

With no recycling options available in the U.S., Trek engineers have found other ways to reduce the company’s carbon fiber waste.

Manuell said Trek recently invested in software that helps it use its raw carbon fiber material more efficiently.

The manufacturing process begins with long, 24-inch-wide sheets of carbon fiber material, from which assemblers cut the shapes for components.

“We cut shapes out of those like you do with a cookie cutter,” Manuell said. The question, he said, is “how closely can you notch those cookie-cutter shapes together to most efficiently use that material?”

The software lets Trek reclaim an extra 5 percent of the raw material, which otherwise would go to a landfill.

“That came out of waiting too long to find someone that’s actually finding a way to recycle or use this material,” Manuell said.

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