John Winters wrote: > There may be chopped glass in the mix although the fiber length may be > short so they are not easily discerned. Also, polyester adhesive mixes are > not unusual and do hold up quite well when the resin used is flexible > enough for the job. With time polyesters do get more rigid and maybe the > resin Eddyline used was not as flexible as it could have been. Production > demands often eliminate epoxy as a practical adhesive. I think you nailed it here, John. This stuff is hard as a rock, and the fillet is very thick in places -- giving essentially no flex. BTW, the technician I spoke to at Eddyline recommended epoxy/glass as a fix -- could be they now use that. When I was up there a year ago, looked like they were using a Cabosil/polyester mix, but they may have switched, since. > Since kayaks are rather flexible the coaming joint can be the stiffest part > of the deck. This invites failure so the best adhesive is one that has > enough elongation to accomodate the flex of the deck. Sikaflex 292 is a > good flexible adhesive for polyester joints. I would rate it better than > epoxy since it allows movement. There are other similar adhesives but those > I am familiar with are industrial materials and not readily available. [snip] Gotcha. I'd use Sikaflex if I had the energy/time to remove the whole coaming insert. The failed segment is only 18 inches long along one side, so I think I'll go with something having compliance comparable to the rest of the joint. > You would need a good "tooth" for the epoxy too and you should be sure all > the brittle filler is removed or the joint will fail again at the > epoxy/polyester filler interface. [snip] Good advice. > The flooding is a bummer. Be cautious with the support to the hull. You may > cause a hard spot that could cause a hull failure. Sea kayak hulls and > decks tend to thin and joints should give a bit and not cause "Hard" spots. Yeah, aware of that. The failure of the coaming joint is really my fault. I removed the stock seat (integral with the coaming) and "extended" each tang with a screwed-on flange of polycarbonate sheet, leaving a quarter-inch gap, which I filled with a sandwich of hard black rubber and softer foam. I'd have been OK with this arrangement, but somehow my sandwich got flushed out on one side, and the lack of support on that side allowed my 100 kilos to delam it on exit. (I usually lift myself out using the cockpit rim.) I'll make sure the sandwich does not leave this time! I much appreciate your very professional and highly knowledgeable advice, John. Your expertise, alone, makes PW a terrific resource! Thanks for the response. -- Dave Kruger Astoria, OR sea kayaker -- and chemist *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************Received on Wed Jun 24 1998 - 04:08:29 PDT
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