My AB Hypalon RIB
is also an oldie. It was vandalized a year ago in a way intended to be non repairable. I have considerable experience fixing these, but this was a challenge because the numerous cuts were close enough to require one large patch, as well as RIGHT next to the rub rail, where there was no room for a patch.
I always keep a square foot or two of my dinghies color of Hypalon fabric
around. My preference is two part Bostick glue, but it has a very short shelf life, so when cruising, I carry their one part as well, which has a longer shelf life. In over 50 patches over the last 35 years, none have ever failed. (with either type)
I cut the patch with rounded corners, or totally round, then, after thorough acetone washing
of both parts
, I scribe it on the dinghy
. Then I tape all around what I have scribed with my favorite tape, 3-M 471 blue plastic tape. (NAPA) This stuff is solvent resistant and abrasive resistant too. Next I use a dremel tool to abrade both the dinghy
and patch underside to a consistent fuzzy appearance, without removing to much.
Next, I QUICKLY apply the glue as thinly as is still 100% covered, to surface A and surface B, with a small acid brush. Now wait 15 minutes until dry. Repeat the coating process. Now wait only 5 minutes! (If the glue instructions differ, ignore them)
After this 5 minutes, carefully roll the patch into position on the masked off area. (no bubbles)
Next you can remove the tape, but hold the patch down as you go, so as not to pull glue out from under the patch. This is followed by first, "firm as possible pressing", then hammering a bit, with a rubber hammer and something soft underneath.
For a really neat job, I finish up with acetone removing any excess glue from around the patch.
In this case, I had to remove the rubrail first, apply the patch, then re-apply the rubrail.
To remove any glued on part, you heat it with a glue gun, waving it back and forth, to heat the 6" in front of where you are working.. At the same time you use a putty knife to lift
the part, GENTLY. Apply heat very gradually, and there is a point almost, BUT BEFORE the fabric comes apart, that any glued on part just comes right off.
After making my patch where the rubrail had been, I re-applied the rubrail, just like a patch. (All day job)
The other problem was that over 10 years, every seam on the boat, had their edges all fuzzy and frayed, where strings of the fabric core
were coming out, and a bit of the Hypalon outer layer were flapping up.
To fix this, ONE SEAM AT THE TIME... I masked off both sides of the seam (same tape as above), and first I worked 5200 under the outer layer of Hypalon. Then wiped the outside clean with solvent, and applied a third row of tape right down the middle, to glue down the flap. A couple of days later, I peeled off the 3-M tape, and repeated the process of taping the seam. This time I made a 1/8" wide bead of 5200 right on the exposed edge of the seam, and immediately pulled the tape on each side.
I basically glued down and then covered the edge of every seam on the boat! It has held up for a couple of years now, and I think I'm good for 10 more years!
This process did take a couple of weeks and couple of hundred dollars worth of tape and caulk, but the dinghy was both expensive, and it had a cradle
and many other labor intensive accessories made just for it. Otherwise I might have just bought a new one...
For some folks, it is worth the effort... BTW, Beware of aluminum
floor RIBS, if you want longevity. (ours is fiberglass) The aluminum
floor models have a weak link, it is the bond between the paint
and the aluminum. The tubes are glued to the floor after the floor is painted, and before the glue job fails, the paint
bond usually does. At least this has been my observation.
Hope this helps, Mark