Composites are almost perfect materials — lightweight, strong, and incredibly versatile. But to make them truly perfect, we need to close the loop. That’s why we were thrilled to take part in the MC4 Project: a European initiative focused on boosting the circularity of composites. Because for us, innovation doesn’t stop at performance — it means rethinking how materials are designed, used, and re-used.

Figure 1. Final review with the European Commission at the Waste Lab Bizkaia

How We Applied Circular Composite Manufacturing in Project MC4

For the MC4 Project, the European Union selected 16 European companies with advanced technical capabilities to address every stage of improving composite circularity. Collaboration between partners was essential — not only to develop innovative solutions, but to ensure they could work together in real-world applications. At Managing Composites, our role focused on the manufacturing of a kayak using 3R vitrimer resin developed by CIDETEC: a reprocessable thermoset that infuses and performs like a conventional epoxy, but can be softened with heat, reshaped, and reused. The infusion was carried out at 60°C, the initial cure at 130°C, and the post-cure at 150°C — validating a process that aligns performance with circularity.

Figure 3. Asier Martín, Ronan Lecoeuche, Eduardo Nicolás representing Managing Composites at the final review presentation of the project

The kayak itself was conceived as a hybrid between a touring and a sit-on-top model — a deliberate choice to combine performance, accessibility, and manufacturing simplicity. Designed with circularity in mind from the outset, the hull and deck were built in two bonded parts, featuring sleek lines and clean surfaces to facilitate both fabrication and future transformation. The masters were produced using proven marine construction techniques: low-density foam cores, hand-laid glass fiber layers, and resin paste, all CNC-machined to the final geometry. To ensure dimensional stability and reusability, the molds were reinforced with a hybrid of carbon and glass fiber.

Reprocessing Composites: A Real Example of Circularity in Action

But building the kayak was only half the challenge. To truly demonstrate the potential of circular composites, we had to go further — and that meant deconstructing what we had just built. After testing, the kayak was trimmed, cleaned, and carefully flattened using heat and pressure. The recovered laminate was then bonded using a vitrimer adhesive and repurposed into a new form: a paddle. The transformation was done in a precision-machined stainless steel mold, under 180°C and 40 bar of pressure. Once cooled, the new component was trimmed, finished, and painted — completing the journey from product to raw material to product again.

Figure 3. The repurposed kayak was exhibited at the 2025 JEC World in Paris.

This process demonstrated how circularity can be applied to composites — not as a theory, but as a viable manufacturing reality. We now know what it takes: the right materials, the right design strategy, and a clear end-of-life plan. The next step is to bring this vision into real industrial environments — scaling processes, optimizing costs, ensuring repeatability, and adapting to production realities without compromising on performance or sustainability. At Managing Composites, innovation and experimentation are part of our DNA. Projects like MC4 are not the end goal, but a starting point — another step forward in our commitment to push the boundaries of what composites can do.

The post From Kayak to Paddle: Making Circularity Real in Composites appeared first on Managing Composites.