Howdy. After about 10 fun years with my old Allagash, I really want D rings to hold down my flotation bags. I use it for solo and tandem whitewater races (which we have a lot in Bangor!) but the float bags start popping up through the ropes after a while. I tried G flex with NRS Drings: sanded surface, cleaned with alcohol, put sand bags on overnight… they popped right off like flapjacks!
I believe the outer build is polylink3, but I’m not sure the interior/hull is the same.
I’ve had some luck with Goop and even silicone caulking in the past: what is my best option? Kinda disappointing to go out the next day and break them all off by hand…
G Flex will bond to polyethylene, which is what the inner surface of you hull is, but you will achieve an adequate bond only if you pretreat the hull surface with flame oxidation right before applying the epoxy.
If you omit this step the bond will not be worth a damn. I have used G Flex to bond vinyl D ring patches to polyethylene canoes and to repair three -layer rotomolded polyethylene canoes and single layer polyethylene kayaks and C1s. With proper surface treatment G Flex has provided a durable bond.
Below is a photo of an Old Town Allagash 174 three layer-polyethylene canoe that I did extensive repairs to years ago. The boat had erosion into the central foam core at both stems over a very large area which was filled in with G Flex, then covered with a fiberglass patch bonded with G Flex, and finally covered with large, Dynel skid plates, one of which is shown.
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Awesome job! Although I can’t imagine what kind of trauma it took to tear through an Allagash: (class 5 rapids?)
I’ll try it again WITH flame oxidation this time… (those little D-rings can get expensive…) you do still sand it first, right?
Thanks so much
Yes. I would first wash the hull with a degreasing detergent like Dawn dishwashing liquid. Then sand the area of application with 120-150 grit sandpaper. Wash and rinse again. Then wipe the hull surface down with denatured alcohol.
Make sure your alcohol has very fully evaporated before doing the flame oxidation bit to avoid a flambe. All you need is a torch head that screws onto one of those taller, thinner liquid propane canisters. You can find these at just about any hardware store if you don’t already have one.
Do the flame oxidation in relatively dim light so you can clearly see the inner blue cone of the torch flame. You want just the tip of that cone to contact the hull briefly but make sure you cover the entire surface to which you plan to apply epoxy. Do this no more than 30 minutes before applying the epoxy but the less time the better as the oxidation of the polyethylene is only temporary.
Apply a thin coat of G Flex to both surfaces. I prefer to use the unthickened variety but you can probably use the prethickened G Flex if that is what you have. Mask around the area to which you apply epoxy to avoid getting epoxy on the hull where you don’t want it. After approximating the patch to the hull apply a little tape to the edges to keep it from shifting and weight the surface as you did.
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Thank you for such perfect directions: I can’t wait for the new rings to get here to try this out.
Ps here is the old tank: the skid plates are starting to wear through, but she’s still water proof and ready for anything!
Ps I measured and apparently she’s only 16’4”!
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I used plain 'ol Weldwood contact cement (red label can or bottle) in my D rings in several of my Royalex boats as have many of my compadres and they are holding just fine after 10 plus years. Prep is key, making sure all surfaces are clean. I have found that the type of D ring is almost as important as the adhesive. You want then to be as flat on the bottom as possible, no extra material that can cause an airspace or allow dirt or water to infiltrate.
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And my experience has been very different. I tried using DAP Weldwood contact cement (flammable variety) to bond vinyl D ring patches in several Royalex whitewater canoes in years past.
DAP Weldwood works great for foam installation and it can work for D rings that don’t have much or any distracting forces applied to them. When I tried it for thigh strap anchors which are subject to significant tension they all failed in fairly short order.
Even when I used contact cement for D ring anchors for “keeper straps” to secure flotation bags which are subjected to much less tension it didn’t hold up.
I also tried a product called “Hydrogrip” sold by Perception back in the 1990s which was described as a “water resistant contact adhesive” marketed specifically for boat outfitting. That did not work for me either.
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So I got my new d-rings from NRS (only 4” ones are left till September!)
It’s remarkable the difference using that blowtorch makes! Last time I carefully prepared and meticulously cleaned, and each patch popped right back off like nothing.
I followed pblanc’s instructions carefully: it took a few days since you can only do one side each day, then weight them down. I made every rookie mistake possible: I did flambé the boat (alcohol not dry yet!) then in a hard to reach spot, I went too long with the flame and it bubbled and melted a little… but by the end I got a lot better… and they are all stuck ROCK HARD! WooHoo! Thanks everyone!
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I’m glad it worked out for you. Yes, the flame oxidation is a little tricky. You want to make sure you touch all of the areas that you are going to apply epoxy to, but you need to keep the flame moving along quickly.
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