sparty,
No experience with G-Flex. We used SC2000 for our hypalon dinghies, and it worked well both above and below the waterline. You can probably locate some, it is used as conveyor belt
adhesive in the
food and mining industries.
Guy, above, is correct, the heat gun should soften the old [probably Bostik] glue. However, it does not
work on SC2000.
Ann