As most of you know I have made a couple riverboards out of kayaks and love the performance I have gotten from them. That said, I am having problems keeping the foam glued to the old kayak hull. Does anyone have any experience. I first used 3M spray adhesive #90 with luck for about 5 runs before having to re glue. I then pulled the foam out and started over with Gorilla glue. I have 8 runs (over 30 miles) but it too is beginning to give up the ghost. Any suggestions?