My keels are not hypalon, they are made of black PVC. I have no idea how Zodiac originally bonded the seams/ends. I have sucessfully patched them (and small tears in the Zodiac roll up floors) using 7096 all purpose glue. Zodiac used to sell hypalon keels for a MK3 F, part # 3038N which some preferred over the PVC. Those keels should be repaired with 7098 Hypalon glue.