Paddleboard productivity: Adhesively bonded hull/deck is key

Dragonfly Boatworks LLC (Vero Beach, Fla.) owners Mark Castlow and Jimbo Meador, avid fishermen and makers of kayaks and shallow-water fishing skiffs, had an idea they couldn’t shake: find a way to access very shallow water for stealthy fly fishing, yet stay dry. The solution was a stand-up paddleboard. Designed more like a boat than a surfboard, with a chined hull and water-shedding deck details, it’s available in two lengths. The longer version, at 13.6-ft/4.2m, is buoyant enough to support up to 420 lb/191 kg.

The paddleboard’s unique design is much different from that of other recreational paddleboards, which resemble surfboards. Dragonfly’s two-piece construction integrates a separately molded hull and deck, each a layup of woven E-glass in a vinyl ester matrix. To eliminate the weight and labor associated with fasteners, Dragonfly turned to SCIGRIP Smarter Adhesive Solutions, a wholly owned subsidiary of IPS Corp. (Durham, N.C.), for a hull/deck bonding solution. SCIGRIP recommended its SG200-40 methacrylate adhesive. Applied in a 0.25-inch/6.35-mm bond line, it not only ensures adequate bond strength, but also, due to its unique rheology, prevents water from entering the board’s foam-filled interior section. No additional sealing steps are required after the hull pieces are joined, says SCIGRIP.

Castlow says, “SCIGRIP’s SG200-40 adhesive is ideal for our paddleboards because it creates a lightweight, yet strong adhesive bond. Using SG200-40 has improved our paddleboards’ performance and reduced labor and production cycle times.”

SCIGRIP has a comprehensive offering of high-performance marine adhesive technologies, says Kirk Miller, SCIGRIP’s regional sales manager, “The SG200 series can be used for bonding a wide range of materials in personal watercraft applications.” The two-component, 10:1 mix ratio adhesives bond thermoset and thermoplastic composites and metals to like or unlike materials, with minimal surface preparation and a choice of working times (10, 20 and 40 minutes). SG200-40 helps maximize manufacturing efficiency by providing Dragonfly with enough time to accurately position the parts for bonding.

The adhesion properties include tensile strength of 2,000 to 2,500 psi (14 to 17 MPa); lap shear strength of 2,400 to 2,800 psi (16 to 19 MPa); and tensile modulus of 60,000 to 75,000 psi (413 to 517 MPa), measured at 75°F/24°C. The packaging options include 490-ml/0.95-pint cartridges and 5- or 50-gal (19- or 189-liter) bulk containers for application with meter/mix/dispense equipment.