Grab Rails (again)

Seeking advice for a project or do you want to share the outcome of one? Various technical tips and questions.
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TimOnders
Posts: 160
Joined: Mon Mar 10, 2008 4:47 am
Location: USA, WA, Seattle

Grab Rails (again)

Post by TimOnders » Sun Oct 04, 2020 3:21 am

The forum has been a little quiet, so I thought I'd post something.

Over the years, we've had recurring leaks around the cabin top grab rails. They get stepped on or just frequently used, and the seal between the teak and fiberglass, or around the screws, will eventually open up enough to let the rain in. Usually we just take the screws out, re-bed the three grab rail sections (the long front trim section has stayed tight, so we don't mess with it) and be done with it. However, this time I've noticed enough of a moisture problem inside to make it a big project.

The exterior grab rails are attached with screws that go into the interior grab rails. The interior grab rails are fixed to the interior trim, and the interior trim is glued to the cabin top with big blobs of Sikaflex. So, not easy to remove, which is why we never have. However, this time, two of the four blobs of Sikaflex had come loose, so it seemed to be an opportunity to give it a shot.

The reason one of the blobs had come loose turns out to be a manufacturing defect. The interior fiberglass on the Dufour 34 is finished in an almond-colored flow coat over the white gelcoat used in the molding. Because the flowcoat is applied on top of the finished gelcoat, they apparently mask off any areas where something may be fastened with adhesive (like the trim) since the bond between the almond layer and the base gelcoat isn't going to be perfect. However, I discovered that the workmen neglected to remove the masking tape from about a 1m section above the galley, and the Sikaflex blob was actually adhering the wood to the masking tape rather than the fiberglass. After 17 years, the masking tape adhesive finally gave up at that point. Additionally, the masking tape turned out to be an excellent substrate for mildew growth from the moisture from the recurring leak. Another good reason to get the trim off.

By the way, they also glue the wiring for the lights in with Sikaflex to keep it out of the way while the trim is being bonded in place. Someone really needs to keep this annoying material away from the Dufour carpentry department.

I'm now trying to figure out the best way to put everything back together. For the grab rails, I don't want to just use the same screws again, since they always leak and they seem a little undersized (not sure what the original metric size was - I had a yard do the re-bedding last time and they [annoyingly] swapped in #10x3" screws in place of the originals). I can't easily get to the underside of the exterior grab rail, since I don't want to take it completely off (I'm worried I'll break it while trying to get the front part off). So, that limits my options somewhat. I also would prefer not to use sealant to glue the interior trim back up, but I don't see any good alternatives.

On the grab rails, I figure part of the problem with the leaks is that the screws can't be tightened after the sealant is in place, since turning the screws will break the seal around the threads. I'm thinking of using studs screwed into the interior grab rails, and then use nuts and washers under the wood plugs on the exterior grab rails (the aforementioned yard also over-bored the 10mm plug holes to 1/2" since they didn't have a metric plug cutter on hand - very annoying). However, that seems a little complicated, and a bit of a risk of screwing up the grab rails.

The other alternative I am considering is to use threaded inserts in the interior grab rails, and machine screws through the external grab rails. That doesn't solve the screw-through-sealant problem, but it would help with the interior wood weakening from removing and re-fitting the screws 5 times, plus any water damage from the leaks.

The simplest option is probably just to go up one screw size (#12). That would require the least modification, although may just be kicking the problem down the road.

Anyone else done any work on their grab rails over the years (particularly the internal trim)? We've done pretty well keeping her looking sharp over all these years. I'm really worried about screwing something up, particularly since I don't have a source for the interior wood or veneer.

Best,
Tim
s/v Frog Prints
2004 Dufour 34 #057 (2003 built)
Seattle, WA USA

P.S. Along with the masking tape, I've also discovered a sheet of release fabric or something that was left when the grid pan was attached to the hull. I can feel it in the space between the pan and the hull by the nav station. They must have had an extra bottle of wine with lunch that day.

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