ThreeSixFiveMedia Nick Bigeau and Amy Russell of Resolve Composites inspect reclaimed fiberglass laminate material they stripped of resin using their solvent-based composite materials recycling process.
I first visited Tern Boatworks (Lahave, Nova Scotia) in the spring of 2022. At that time, the two-campus boatyard with a crew of about 12 was focused on readying the storage and service fleet for the looming summer season, while simultaneously restoring a locally built wooden Cape Island boat, an historic 40′ (12.2m) Nova Scotia schooner yacht, and retrofitting an electric auxiliary propulsion in a fiberglass daysailer. An admirably diverse portfolio—even by the inclusive standards of the average small full-service boatyard—I quickly found myself deep in discussions about Tern’s more cutting-edge experimentation with natural fiber composites. (For more on Tern Boatworks, see Melissa Woods’s “Young Canadians” in Professional BoatBuilder No. 171, page 60.)
At that time, the notion of applying flax or hemp as laminate material in marine composites was very outside the norm and, in my experience, limited to some forward-looking European boatbuilders with climate-driven regulatory changes and research funding spurring them on. It wasn’t an area of inquiry I’d expected to encounter at the core of a modest Nova Scotia boatyard, but I was quickly swept up in the enthusiasm of Tern owner Bruce Thompson and his composites expert Nick Bigeau. As they made their earnestly pragmatic case for building boats with renewable composites, our discussions of carbon footprints, thermoplastic vs. thermoset resins, recycled PET core materials, and peculiarities of vacuum infusing natural fiber laminates returned to the frustrating reality that no build option was truly recyclable as production waste or at the end of a boat’s useful life. Numerous materials promised recyclability, renewability, and “greener” composites, but the best options at the time were to grind up the composite waste for incineration or use as filler in lower-grade materials. Thompson and Bigeau had innovative ideas and some specific plans to build a prototype boat of natural fiber laminates, but we agreed that there wasn’t anything conclusive to report out yet. They’d be in touch when they had something to share.
Courtesy Resolve Composites Tern Boatworks owner Bruce Thompson and Nick Bigeau review the plans for a center console skiff they are building with laminates reclaimed from a discarded wind turbine blade.
Two-and-a-half years later, I got the call I had been only half expecting. They had a new spinoff composite technology company (Resolve Composites), a solvent-based process to pull cured thermoplastic or thermoset resins from discarded composites (ReceTT) and were building a small boat out of fully reclaimed fiberglass laminates.
“We were initially going to build a boat with flax fibers and Elium (thermoplastic resin), but it was bugging us thinking, ‘How do we know that this is going to get recycled?’” Bigeau said, when I visited their snow-bound boat shop in Gold River, N.S., the last week of 2024. Knowing that only 8% of plastics get recycled, he and Thompson realized there were slim odds that an Elium hull would be responsibly disposed of just because it was theoretically more recyclable than a polyester or conventional epoxy structure. The leading issue for them had become the practicality of composites recycling for boatbuilders and service yards.
“We thought we’d engineer a boat so it could be recycled,” Thompson said.
“Basically, we’d build a boat, then recycle the boat and try to reuse the materials and rebuild the boat,” Bigeau explained. Thinking of the boat as a matrix of components that ideally could be disassembled and reused without changing their form or basic properties, pushed the team to prioritize the reusability of materials. In that context natural fibers offered few benefits, but robust glass or carbon fibers that could be reclaimed and reused multiple times held great promise.
Bigeau’s research started with Elium resin, which he says is most promising when it comes to reclamation of the resin particularly through thermolysis, but requires volatile, expensive, and tricky-to-handle solvents to clean it from fibers you hope to reuse. (For more on Elium thermolysis, see “Building in Circles”) In Tern’s working boatyard environment, those qualities presented significant liabilities, but Bigeau’s next discovery, Recyclamine from Aditya Birla Advanced Materials, was a good fit. It’s a thermoset epoxy with an active ingredient in the hardener that makes it recyclable. It can be stripped from the laminate using a relatively mild acetic acid solvent and without high-temperature treatment.
Bigeau and Thompson had been thinking they might have to send the boat they were planning to build, then recycle, to a specialized contractor for the solvolysis. However, after talking with the Recyclamine technical staff, they realized it would be possible to process the end-of-life composites in house with relatively accessible materials, equipment, and facilities.
Building the Test Panels
The first step in proving feasibility was to build 1 sq ft (.09m2) composite test panels with fiberglass laminates and Recyclamine resin, break some of them down in a bath of the acid solvent, reclaim the fiber, and create new panels from the recovered material.
ThreeSixFiveMedia Composite test panels were infused, cured, and broken down through solvolysis. The laminate material was then reused to create new panels.
At that scale, the process went smoothly for the boatbuilders accustomed to much larger projects. Their sample panels of virgin and recycled fiberglass are largely indistinguishable to the casual observer.
To delve deeper, Bigeau sent coupons to the Composites Research Network at the University of British Columbia for tensile, flexural, and facesheet testing.
Courtesy Resolve Composites Coupons of virgin and recycled laminates underwent tensile testing at the University of British Columbia.
Courtesy Resolve Composites The lab also performed flexural testing on cored composite panels.
Lab results indicated that tensile properties reduced on average 10% in the second-generation panels, which makes them completely adequate for boatbuilding. Likely contributors to the difference are fiber misalignment and the absence of sizing that enhances resin adhesion on the reused fibers. Bigeau noted, with some surprise, that the facesheet and flexural properties had improved in the reused-fiber test panels. He speculated that these gains were due to the recycled fibers being compacted or debulked repeatedly under vacuum, resulting in a higher fiber-to-resin ratio. There’s more testing to come on this subject.
Next, the Resolve team built a bow section splashed from an outboard skiff in the yard to check the practical challenges of subjecting a larger composite structure to solvolysis without cutting it up. This step was essential to their ambition of reclaiming large sections of laminate material that could be reused in a new structure.
ThreeSixFiveMedia The process was tested on a foam-cored bow section built for testing.
ThreeSixFiveMedia The reclaimed PET foam and glass laminates.
The bow was built of two layers of biaxial 1708 fiberglass infused on either side of a foam core—essentially the layup for the prototype boat they were planning, Thompson said. But it was far bulkier than anything they had previously processed.
With the small test panels, Bigeau said, “We put the solvent in a beaker, we broke it down, and we reused the materials, but we didn’t have a process yet.” Following the same model, the approximately 4′ (1.2m) bow section would require a big tank of solvent to break it down. Bigeau estimated they’d need 1,400 liters (317.8 gallons) of solvent, which was really a deal killer. It was just too much solvent to conveniently handle, store, and process at the boatyard.
“I was thinking we’d need big tanks and to clear the shop out for a week to do this,” Bigeau said. “It starts to become problematic.”
At this critical point the Resolve team improvised an entirely new approach that cut the solvent volume to a scant 144 l (32.7 gal). Now patent pending, their “ReceTT” process is basically a reversal of resin infusion, “circulating solvent over the surface area of the part,” Bigeau explained. It allowed them to break down the chunky bow section in eight hours without cutting it up and to reclaim all the laminate materials in their full assembled dimensions, and the thermoplastic material from the Recyclamine resin. The circulating pump and heater consumed roughly 37 kilowatt hours (kWh).
Mission accomplished as far as securing the materials that could be reused to build a new boat as originally planned. But on the way, they’d stumbled on a fortuitous distraction—discarded wind turbine blades—that would reroute the boatbuilding project.
Wind Shift
In researching Recylamine, Bigeau learned that Siemens Gamesa, a Danish wind turbine builder, was producing full-size blades with the resin in expectation that they could be fully recyclable at the end of their service life. The effort won an innovation award at the 2022 JEC World composites show in Paris, but many practical details of how the big blades would be broken down for reuse had yet to be worked out. Bigeau saw a potential source of large composite structures built with Recylamine that could yield high-quality laminates for his boat project. The possibility of using an existing discarded blade rather than building a boat, breaking it down again, then reusing the salvaged laminates to build a new boat, was appealing. Siemens Gamesa was interested. They agreed to collaborate with Resolve on the Second Wind Project, to build the 17.9′ (5.5m) skiff Thompson and Bigeau had been planning to build as a technology demonstrator.
They shipped a portion of the blade’s spar cap (a highly reinforced strip located at the top and bottom of the blade’s airfoil section) to Nova Scotia for testing.
“It was hard to convince them to keep it in 20’ (6.1m) lengths,” Bigeau said, “but I wanted to demonstrate we could do full-length composites.”
What arrived was a 240 kg (529.1-lb) 1m x 6m x 57mm (39.3″ x 236.2″ x 2.2″) section of blade surface laminate comprising multiple layers of stitched unidirectional fiberglass skinned with 12-oz biaxial cloth. The crew set up the blade fragment on a shop bench and subjected it to the reverse-infusion process they’d practiced on test coupons and the bow section. It was all done at 80°C (176°F), while sharing the shop space with other boatbuilding projects, Bigeau said. So, not too precious or unapproachable for a standard boatyard. The only glitch he reported was the need to upgrade equipment including the pump to address changes in solvent viscosity with resin saturation. This first project involved experimentation over a couple of months, but Bigeau projected it would take about a week under more normal shop conditions with standardized processes and gear. The results were all that Thompson and Bigeau were hoping for: clean, large-scale laminates that looked like new fiberglass material that has been re-rolled and stored on the rack.
ThreeSixFiveMedia Amy Russell cuts some of the recovered fiberglass cloth on the shop floor to use in building the prototype Bantam Bay skiff.
Courtesy Resolve Composites Rolls of glass reclaimed from a 20′ (6.1m) section of wind turbine blade spar cap and the barrels containing the acetic acid solvent that dissolved the Recyclamine resin from the laminate.
“It validates Siemen’s choice in the resin, and it validates the Recyclamine technology” Bigeau said. “Where our technology comes in is that we were able to do it at this scale.”
While most composites recycling and reuse efforts rely on chopping and grinding materials before including them in a new structure, Resolve’s approach is to keep the laminate material intact and in usable sizes, thereby minimizing energy and labor demands of the process and maintaining material properties consistent with those of original laminates.
“Why chop up materials when you can do it like this?” Bigeau asked, as we unrolled some long samples of unidirectional and biaxial glass on the bench. Rinsed in warm water following solvolysis, the dried reclaimed materials, including some carbon fiber they had processed, preserved the drape and handling qualities of the originals, though Bigeau confirmed that the glass would not have the sizing of the virgin cloth. They salvaged 170 kg (374.8 lbs) of usable glass from the blade fragment, most of it destined for the boatbuilding project and additional testing.
As proud as the Resolve team is of the quality and quantity of reclaimed fiberglass, and the minimal energy input required, Bigeau is clear that this isn’t a waste-free process. At the end of their project, the extracted resin was suspended in 908 l (206.1 gal) of 25% acetic-acid solution. By raising the Ph, the resin can be forced to precipitate out and be separated as a crumbly material that Bigeau said he isn’t sure what to do with… yet. He’s hopeful the Recyclamine chemists will be able to reuse it in formulating new resin in much the same way that elements of thermoplastic Elium resin extracted during thermolysis of composite production waste can be reused.
Beyond Thermoplastics & Recyclables
Having developed the promising solvent-saving ReceTT process, the Resolve team took a detour from the boatbuilding project to explore whether it could be applied to composites made with conventional epoxy (non-Recyclamine) resins. Samples of the resulting reclaimed laminate materials were pliable but stiff with lingering resin. You’d never mistake them for new material, but yielded properties attractive to commercial boatbuilders for low-stakes applications like interior panels. They haven’t done lab testing of the samples yet.
By testing different solvents, the team looked to maximize resin-stripping while avoiding damage to the fiber material. In one test, the solvent dissolved resin but also the polyester stitching that held the layers of unidirectional fibers of the original cloth in place. Bigeau had a sample of new material restitched with nylon by a neighboring sailmaker for the next test panel, and the nylon survived the solvolysis. Of course there isn’t a material producer stitching with nylon, but the proof of concept means there could be if there appears to be a scaled market demand for it in the future.
Other experiments confirmed that a builder’s material choices might have to change to meet the needs of evolving recycling technologies. For instance, Bigeau explained how foam core from recycled polyethylene terephthalate (PET) has a low installed carbon footprint, but it breaks down in some solvolysis processes, contaminating the resin you are trying to recover. In that context, using styrene acrylonitrile (SAN) foam, which may not be readily recyclable but can be separated through solvolysis, could be a greater environmental benefit. It all points to the need for careful deliberation before choosing the technology to best breakdown legacy composites or to build new composite structures.
As a worst-case, real-world test, Bigeau sourced a section of nonrecyclable wind turbine blade comprising PVC core, thermoset resin, bonding putty, balsa core, fiberglass cloth, and polyethylene coating. Running the ReceTT process at room temperature, they were able to separate the fiberglass, coating, resin, foam, and balsa. While most elements were left moderately contaminated by the process, the disassembly allows for separation of material types for further processing or disposal. For instance, glass or carbon fibers are left at usable lengths and uncontaminated by the chlorine and bromine that would have resulted from pyrolysis of PVC core material.
Courtesy Resolve Composites All the components recovered from another blade section, this one built with nonrecyclable thermoset epoxy resin, using Resolve’s ReceTT process.
Courtesy Resolve Composites The original section of laminate.
That potential to pull apart the components of a composite structure without grinding them up into a slurry of incompatible materials sets the ReceTT process apart from conventional recycling efforts.
“Mechanical grinding was meant for paper, cardboard, and metals. It wasn’t really meant for composites,” Bigeau said. He’s committed to identifying the methods and virtues of separating various composite materials and maintaining them in their most useful forms or dimensions for reuse or disposal. That includes the possibility of subjecting some of the materials to additional processes like pyrolysis following initial solvolysis treatment.
Bigeau said he found strong interest in ReceTT solvolysis at the March 2025 JEC World show, where European composites manufacturers facing legislative requirements for recycled content in new structures have an open-minded approach to reused materials.
The Boat
Back at the boatyard, Thompson and Bigeau had removed the long-awaited 17.9’ (5.5m) Bantam Bay skiff to a storage space to accommodate a large yacht restoration in the main shop over the winter. Built in a split mold to accommodate an attractive measure of tumblehome, I could see the two halves of the V-bottom boat in differing stages of completion, one infused and the other with laminate materials still being loaded. If you didn’t know better, it looked like an ordinary build.
Courtesy Resolve Composites Reclaimed unidirectional and fiberglass fabric is placed in the skiff mold with recycled PET foam core prior to resin infusion.
Courtesy Resolve Composites The unidirectionals, shot through with striped longitudinal stiffeners that were part of the custom wind-blade laminate material, were layered and oriented carefully at 90 degrees to yield a biaxial equivalent structure upon infusion.
“It’s all unidirectionals except for the two skin pieces which are biax,” Bigeau said. The only clue that the laminates were out of the ordinary was the series of thermoset stiffeners visible in the 24-oz unidirectionals. They were in the original specialized wind-blade laminate material and not broken down by the solvent during processing. They made it challenging to shape the glass around tight corners at the skiff chines. Some judicious trimming and pairing of the unis to create a +/- 45° laminate on either side of the ½” recycled PET foam core, coupled with taping and 12-oz biaxial skins, delivered an overbuilt hull laminate for what will be an able workboat for the yard.
The completed skiff will be a very different boat than the one they discussed with designer Laurie McGowan when he drew up the lines for a boat to test natural fiber laminates in 2022. The lessons the Tern Boatworks team learned along the way have spun off a separate company with patents, international partners, and a growing reputation as part of the solution to the composites recycling challenge. Bigeau insists their solvolysis process isn’t a solitary answer to the need for a change in end-of-life processing of composite boats. Adding it to the growing toolbox designers and builders confronting shifts in regulatory requirements and market demands can work from is what he sees as the best hope for the future of boatbuilding and the broader composites industry.
Planning for how structures come apart and what you can create with their reclaimed materials involves complex, long-range thinking, but it holds the potential to keep old boats and wind turbine blades out of landfills and can lower the carbon footprints of numerous sectors that might be included in the equation.
About the Author: Aaron Porter is editor of Professional BoatBuilder magazine.
