Hull to Deck joint adhesive

[Ryan]

I have searched many posts on the subject, but I haven't seen a definitive answer. Is there a reason to use epoxy over 5200 when re-sealing a hull to deck joint? I plan to use on or the other to fill the gaps in mine, and then lay two layers of glass over the joint to be done with it once an for all. Is it just a matter of personal preference?

[bcooke]

Interesting question.

I wouldn't use epoxy as a 'glue' to mate the deck to the hull. If using epoxy I would mate it with a fiberglass cloth of some type and tab the deck to the hull; several layers worth.

I believe 5200 could be used just like a glue. Squirt it in, clamp the surfaces and forget about ever taken the joint apart again.

So, I would vote for 5200 just because it would be much easier to apply.

My 2 cents.

-Britton

[grampianman]

I have a deck/hull overlap on my Grampian-23. It is very roughly finished and I had the bright idea of straightening the line out as well as sealing the gap between deck and hull. That brightness quickly extinguished as I started to work with the epoxy, etc., upside down, epoxy in beard hair.
The long and short is go with the 5200. I had tried to stuff a thick mix of epoxy into the gap and had pretty good success, but had not been able to roughen the surfaces between - very narrow. After the stuffing exercise, I went to drill holes to re-install the rub-rail and I could hear the deck joint separate as I drilled through. A tiny noise, but there nonetheless.
What I accomplished was a reduction in the gap between surfaces, a fairer surface for the rub-rail, but waterproof hull? No. Of course, I don't plan to cross the Atlantic anytime soon, so should be fine.
Cheers,
Ian

[Ryan]

Britton

My hull deck joint is an overlap type as shown below (old picture, it looks MUCH better now). You can see the pinkish color of the original caulk that was used between the hull and deck (in line with the "headless" rivets. They held the rub rail on). That gap ranges from 1/16" to 1/4" in places. the gap is cleaned and empty of all the old adhesive. That is the place I have to fill in, and then the entire joint will be laminated in two layers of biax. Sorry for the poor description before, I have a horrible habit of inadequately describing whatever it is I am rambling about.

Ryan

[Ryan]

Ian

Thanks for your description, you brought out all the fears I had about trying to use epoxy! I'm am strongly leaning towards the 5200. Thanks again.

Ryan

[Figment]

You're planning to glass-over the joint, so that will take care of securing the two to each other. Adhesive properties should, therefore, have minimal impact on your decision, I'd think.
So you're really trying to figure out what to smoodge in there to smooth the joint prior to 'glassing.

Despite the easily-dispensed packaging of 5200-in-a-tube, I personally would lean toward thickened epoxy. You may want to send a screw in there to secure a rubrail of some sort. I know that 5200 eventually cures rock-hard throughout, but it would be frustrating to have to drill for several dozen screws and constantly get the bit gummed-up with less-than-totally-cured sealant.

(i'm always good for a contrary opinion!)

[george]

I used thickened epoxy, so I hope that is the right answer.

My only concern is that it would be more brittle under micro-flexing and perhaps crack and pop out, but only time will tell.

I have yet to get her in the water, but it survived the water hose test.

[Tim]

Are you actually re-adhering the joint, or simply caulking an open portion of the seam on the outside before beginning other steps?

If you're truly re-attaching the joint, then I believe the adhesive 5200 is the best choice for the true physical attachement. 5200 is, after all, an adhesive, not a sealant, and is best used when its adhesive qualities (which include long-term flexibility) are desirable. Hull-deck joints are one of these perfect applications.

If, however, you're simply filling a gap where you removed the accessible portion of an old caulk, and then plan to externally glass over the area, I might choose thickened epoxy adhesive. With the fiberglass overlay, you'll be creating a firm, immobile joint anyway, and there's no need--nor desire--for the flexibility of 5200 or other sealant. So the epoxy is really there only to smooth out the joint, as Figment also said, and isn't truly required to hold the thing together.