The rub rail is back on the dinghy
I ended up using two different products; partly due to cost but also availability, convenience and I wanted to try both for comparison.
Started with the MarineTex Flex Set epoxy
. Attached the bow section first as that seemed the best way to center the rub rail and have a secure point to stretch the rail out to the finished position on the tubes. It did take a pretty good pull to get the rail to stretch tight and fit all the way to the original end points at the back end of both tubes.
The Flex Set was pretty easy to work with, not too messy and not too difficult to clean up the squeeze out, drips and misses. It does take a few hours for the initial cure so had to secure the rail very well during the process. The directions said full cure in 24 hours but subjectively it seemed much stronger after a few days, however it was on the low side of recommended temps for application.
I did the gluing in sections, roughly a 3 oz applicator's worth at a time. 3 oz kit of Flex Set covered 3-4' of rub rail. Best deal I found was $18.60/kit delivered. The rail is 22' long and I did about half of it with 3 kits so $56 worth did half the rail. This was a good bit less coverage than I had hoped and with no marine
stores within 2 hours drive I was going to have to order another $56 or more worth of epoxy
and wait a week to finish the job. Since 5200 is available locally I decided to give that a try for the rest of the job.
One $20 tube of 5200 did the rest of the rail. Application and curing time was not too different from the epoxy so technique was similar.
A few comments and observations.
1. The epoxy adhered very well to the Hypalon. So well that after it cured fully it would pull the Hypalon away from the fabric
layer underneath instead of the epoxy pealing off. Not quite as well to the PVC rail. After 24 hours I could pull out on the loose, unglued section of the rail and peel a bit away from the dinghy
with moderate effort, the glue pulling off of the PVC rail, not the Hypalon tube. After another couple of days the bond did seem to be stronger and I was not able to pull the rail away from the tube but was not testing as aggressively as before.
2. Even after fully curing the epoxy remained flexible, living up to it's claims in that regard.
3. As expected the 5200 was much messier to work with than the epoxy and cleanup of mistakes
and drips more difficult. Careful masking of the tubes before applying both adhesives was essential. Not only did it minimize the mess and greatly ease the cleanup and trimming afterwards but since both materials took some time to cure the masking was essential to visually insure the rail was mounted in the right spot and to reposition when it inevitably slipped while I was securing it in place for the overnight cure.
4. Securing the rail to the tubes for the curing period was a bit tricky, both positioning the rail and trying to hold the edges of the rail flat against the tube. The edges in places wanted to curl up and leave a gap between the rail and the tube. I used a good grade of duct tape and fully taped each edge section to the tubes as I glued it. This worked reasonably well. There were still gaps in spots but were acceptably small and easy to come back later with a gloved finger and fill the crack with a little more adhesive
, leaving a fairly nice, clean edge.
5. The 5200 seems to stick very well to both surfaces although not like the epoxy. The 5200 I can scrape away the drips with a razor but trying to scrape off the epoxy rips the Hypalon coating from the fabric
I've had the dink out a couple of times now, have inflated and deflated and so far so good. Will report back after a few months for further updates.