Material
Surfboard Materials: EPS Foam + Epoxy Resin vs PU Foam + Polyester Resin
The two traditional construction materials for surfboards are PU (polyurethane) foam with polyester resin and EPS (expanded polystyrene) foam with epoxy resin. Both materials are in addition provided with fiberglass to give the surfboard strength and make it more resilient.
EPS foam is more buoyant than PU foam and epoxy resin is more durable than polyester resin. So an EPS/epoxy surfboard has more robustness and buoyancy for the same construction, so you can choose slightly less volume compared to a polyester board.
Also EPS/epoxy boards tend to be lighter than PU boards, which makes them easy to carry and is great for traveling, and the better durability is an additional pro as EPS/epoxy boards are more likely to survive baggage handlers.
The downside is that an EPS/epoxy board is more expensive as the production process takes more effort. In the water, the lighter weight of an epoxy board can be a disadvantage as in windy, less clean conditions tends to bounce across the water at high speeds when the water surface is choppy. On a polyester board, the contact between the board and the water surface will not break off so easily in comparison. Basically, polyester boards are more “in” the water even when gliding, whereas epoxy boards tend to float “above” the water.
While PU foam can turn yellow over time, this does not happen with EPS/epoxy boards. Epoxy resin, besides its better durability, is less toxic than polyester resin. Polyester resins contain styrene which is subject to increasingly stringent controls on emissions. Epoxy does not generally cause any problems with atmospheric pollution and epoxy resin has 75% fewer VOCs (Volatile Organic compounds) contained in the resin itself and two-thirds fewer VOCs are released into the atmosphere than from polyester resin (VOCs are a source of air pollution and can be a significant health hazard).