Originally Posted by Robpineau
I have used a two part sealant on my early 90's Riken. FLEXSEAL RAFT SEALANT KIT
If this sticks to Hypalon I may try to coat the non-bailing floor on that same raft to seal all those annoying leaks that weep.
I used this on an old, old neoprene raft that had become porus. Following the instructions, I mixed the two parts and injected the sufff--about the consistency of whipping cream--into the tubes through the valves. Then I topped-off the air pressure. A team of us then slowly turned the raft over and over and over in every direction, attempting to get the sealant to flow over every part of the internal surfaces of the tubes.
The result: At every pinhole leak, the sealant was forced through the fabric by the internal pressure. As soon as it hit the outside air, it dried and the leak was permanently sealed. So far, so good. But I guess we stopped turning the raft too soon--even though we followed the instructions--because after we stopped, some of the sealant flowed down to the lowest part of the tubes, where it cured into a thick, inflexible mass that became brittle over time. Leaks resulting from that situation were the end of the raft.