Foam sandwich construction eliminate the need for the putty fillets used in stitch and glue. pre-shaped stiffeners made from a core foam with dry. A tutorial on foam sandwich construction. (stitch and glue spacing of molds and the use of battens depends on the type of core materials: foam sheets or. Stand up paddleboard kit: sup kits we have a wide variety of standup paddleboard kits available including foam core boards, stitch and glue wood construction, and.