How do our boat kits compare to fiberglass and plastic? fiberglass: the combination of just stitch and glue!. What is the difference between our building material stitch and glue a few designers produce plans for stitch and glue boats engineered like fiberglass. Why a bbk is not like a kit. we’ve never actually sold a stitch and glue kayak a bbk is not a plywood boat with fiberglass cloth applied to the outside.