Bio-prepreg guitar: The look, feel, acoustic quality of wood

When the El Capitan guitar from Blackbird Guitar (San Francisco, Calif.) made its debut this year, it had the nostalgic appeal of a vintage instrument. It’s actually made from Ekoa-brand high-performance, eco-friendly natural fiber-reinforced bio-resin materials that offer what the company claims is the stability of a carbon fiber composite but the look, feel and sound of wood. 

Blackbird’s chief musical officer, Joe Luttwak, says Ekoa composites offer 20 to 30 percent higher specific stiffness than fiberglass but lower density than carbon fiber. “We typically use 50-g/m² prepregs for our musical instruments,” he reports. For comparison, Oxeon AB’s (Borås, Sweden and Chicago, Ill.) TeXtreme spread tow carbon fabrics (not prepregged) range upward from 60 g/m², and both Oxeon and North Thin Ply Technology (Penthalaz, Switzerland) offer unidirectional tapes at 30 g/m², the latter highlighting these for space applications. Further, the Ekoa composite exhibits 1.5 percent elongation at fracture and three times the damping properties of carbon and glass fiber. Luttwak also highlights El Capitan’s patented hollow-neck design and explains that every detail has been engineered to generate the acoustic quality and volume of a guitar with a larger body. 

“With the El Capitan guitar, musicians get what was previously unobtainable — the experience of a premium, vintage old-growth wood instrument in a lightweight, durable and sustainable package,” Luttwak claims, calling it “a game-changing instrument” that delivers “unmatched performance and sustainability, while transcending our reliance on ever-diminishing old-growth wood stocks.”

Blackbird spent years developing Ekoa composites for musical instruments, launching first its Clara ukulele line in 2013 (see "Blackbird launches plant fiber-based composite musical instrument," under "Editor's Picks," at top right). Today, Ekoa materials are produced by San Francisco-based sister company Lingrove, which has branched out as a developer/distributor of prepregs, dry plant-based fabrics, bio-based resins and structural cores. Lingrove’s materials can be processed via compression molding, resin transfer molding, resin infusion and hand layup. Applications are expanding to skis, skateboards, surfboards, boat paddles, furniture and auto interiors.