Best sealant for hull deck joint

[SVNeko]

Try Deck-O-Seal

[estarzinger]

Originally Posted by Target9000

Do you happen to know the name or have a link to these sorts of products? I looked around Tremco's site but its greek to me.

Unfortunately I don't know a specific product name. I did have one but it seems to have disappeared in a corporate shuffle.

Do a google on "two part polysulfide sealant", and/or call up one of the industrial sealant distributors and explain what you are doing and ask what they recommend. They will probably be interested and helpful, and you are going to need a case of whatever to fill that gap.

I seem to remember that "Industrial glazing" tends to be the category of highest spec reasonable priced products. They don't want plate glass falling off high rise buildings, but they also use enough that it can't be 'aerospace' priced.

I just looked at tremco's site and it looks like they have been spun off since i had that conversation, and don't do polysulfide any longer. Their industrial glazing sealants seem to now all be silicones and urethanes (which their new parent company provides the base ingredients). Sorry about that.

[Ziggy]

http://www.aquasealindia.com/pdf/sea...lysulphide.pdf

BoatLife also makes one: http://www.boatlife.com/boatlifeclie...Spec-Sheet.pdf

[endoftheroad]

There are many Westsailors with this particular hull/deck joint.
Many sailors will benefit from the info in this thread, including myself.
At this point I'm even more confused......

Thanks Target for inquiring here.

[sailvayu]

The confusion comes form the fact that there can be many solutions to a problem. Many of the suggestions will work and there is no single "right" way to do it but rather several right ways. You just have to pick what makes the most sense for your skill level and resources. The one bit of advice that will work for all, is take your time do a good through job of prepping the surfaces, whatever materials you decide to use follow the manufactures instructions. Do not cheap out on materials just to save a few bucks because in the long run a project like this is more labor than material cost and you do not want to be doing it over anytime soon. Narrow things down a bit and research 2 or 3 products that you think will be best for you. Read about the products online. Then pick one and just do the best job you can. Understand that not everyone giving advice is qualified to do so but you should be able to figure that out. Then like the commercial says, "Just do it!" And most important just try to have some fun doing it!

[westsail42]

Use 5200 for filling the joint. Clean, fill and level it. Let it cure. Re-bed the caprail with something less agressive (Sikaflex).

Methacrylate would not be somewhat of a waste unless you could unbolt and separate the joint (not likely). Besides, it is expensive and has a short working time.

You are just stopping leaks, not re-inforcing the joint.

[roverhi]

The original sealant for the hull to deck joint was a Polysuflde caulk like 3M 101 or LifeCaulk. This stuff does not harden or break down and will be a permanent seal if done right in the first place. The Dolfinite was just a sealant under the cap rail and isn't the real water proof seal. Replacing the Dolphinite under the caprail with something else probably isn't going to be a long term fix if it is a problem with the actual hull to deck joint seal rather than the fasteners.

First you need to figure out where the leaks are actually coming from. Is it the fasteners for the caprail or the hull to deck joint that are leaking?? If it's the fasteners, removing them and carefully resealing with Polysulfide, Polyurethane, or Butyl caulk will solve the problem. If the leaks have been getting worse with age, it's quite possibly the Dolphinite drying out and letting water in from around the fasteners. When you put the cap rail back down, be sure there is caulk around every fastener as it goes into the glass. Screw the cap rail down dry, remove it, run the cap rail fasteners in with the wood off, apply sealant around the fasteners, caulk under the rail and then screw it back down. Also, lightly counter sink each fastener puka so there is a caulk donut where the fasteners enter the glass.

If the water is coming from the actual hull to deck joint, things are a lot more complicated. It may just be a small area where the workers missed with the caulk. On my boat, had one area in the head that leaked. As far as I could tell it was from the hull to deck joint, not the fasteners though I was never absolutely sure. The leak was pretty manini and just stored stuff in that small area in water proof containers. If it is leaks over a large area because of improperly caulked hull to deck joint, the only real fix with the existing architecture is to separate the deck from the hull remove all the old caulk and reseal with your caulk of choice. I like polysulfide, have pulled up pieces that I caulked 30 years ago and the LifeCaulk was still pliable and adhered to the pieces as the day I put it down. 5200 will definitely hold the hull and deck together. Some people swear by it, others swear at it. 4200 isn't as adhesive but you shouldn't really care as this is a task that shouldn't ever have to be repeated. Butyl is another option.

Can't remember whether Westsail used sheet metal screws, machine screws or a combination of the two for the hull to joint. If they did use sheet metal screws, replacing them with machine screws, nuts and washers could solve your problem. Actually, removing all the hull to deck fasteners that are under the caprail and carefully resealing all of them will probably go a long way to solving your leak problems. None of the mass production builders took enough care in caulking the fasteners anywhere on the boats to insure a leak free job.

Another fix that is actually pretty easy to do but takes some skill to get a good finished appearance is to glass the hull to deck joint. Thourougly clean out all the old caulk under the cap rail, clean with Acetone or other nasty solvent. Use gloves and try and do it on a day with a good breeze. Fill all the cracks and crevices with thickened epoxy resin. Grind the surface flat. Grind a bevel 4" or so down the hull and bulwarks several laminates thick at the edge and tapering out as you go down. Don't go crazy with the grinder. Laminate several layers of cloth/matt fabric (Stitched Fiberglass Fabric - Fabmat) with epoxy resin over the joint and down the sides of the bulwarks and hull where you've ground off the glass. Use filler and a foam pad grinder to get a flush finish, paint and then rebed the cap rail being very careful to seal the fasteners. Have seen this done on a couple of the very early Westsails that had a wood clamp instead of the fiberglass flange for the hull to deck joint. If you have a very early Westsail with the wood clamp, that clamp rotting out could be the cause of your leak problems. Glassing the hull to deck joint will be about your only fix.

Former owner/builder of kit Westsail #163

[Target9000]

Thanks for the tons of feedback folks. I've decided we're going to shot the joint with 5200 and then go back with something less aggressive when we replace the cap rails.

To clarify for everyone, there ARE leaks coming in through the actual joint (not the fastener holes). So the goal is to seal the joint itself. The hull to deck is joined structurally on our boat with nuts and bolts and does not have the wooden block in the bulwark. This is how we can look up at the joint from inside the boat and actually see the very specific spots where the leaks are occurring.

I never thought I'd see so many recommendations for 5200 but we'll give it a go.

[sailvayu]

The reason I personally would use Methacrylate is because it is an aggressive adhesive and will bond well to poorly prepped surfaces. it also is very strong and maintains its strength even when applied fairly thick. these are all characteristics needed for this type of application. Leaks start when the bond between the sealant and the surface fails. You need a material that will bond aggressively and not break down to maintain the seal. With larger gaps Methacrylate will bond well and in my opinion better to the 3 surfaces than most other materials. Methacrylate is also very stable and will not shrink or dry out or crack like other materials. Yes it is more expensive at around 90 a tube but like I say this is not something I would squeeze pennies on as removing the cap rail is a major project. I do not think you would need all that much if applied well and not wasted I would think maybe 3-5 tubs a side. Yes that is not cheap but in the over all scheme of things not a lot either. I am sure many will disagree with me but that is ok that is why we have these discussions and it is another option for the OP to consider. I always recommend what I would do on my boat. I have replaced a lot of 5200 over the years in this type of application to consider using it but that is just me. It is up to the OP to consider all suggestions and decide what is best for him based on cost, labor and skill level.

[westsail42]

Methacrylate is not really intended to be a gap filler (though it does hang nicely). It cures somewhat stiff. If there is working of the joint, in such a small area, while underway (hopefully not) it may crack. In this hull/deck joint case, there is not much surface area of the top deck joint for the stuff to attach "onto". So any strength gained will be minimal (unless you can separate the joint and get under it).

A better long term solution would be remove all caprails, grind/clean the joint and glass and epoxy over it. But that would be too much for a dockside project. Time better spent sailing!

[sailvayu]

I would have to disagree about it not being a gap filler as that is one of its main uses. I have done a fair amount of research into it during a a manufacture defect case I worked on and have discussed its properties with the makers. It has a much better elongation than polyester or epoxy making it resistant to cracking and its superior gap filling properties are why so many builders use it for bonding in stringers, liners and hull deck joint without the use of any mechanical fasteners. It is also widely used in bonding aluminum. It is an amazing material really but as you say not cheap. FRP builders like it because it is good where FRP parts are not an exact fit such as hull deck joints. I have done peel tests that indicated it is stronger the the original laminate in almost all cases.

[endoftheroad]

Originally Posted by westsail42

Use 5200 for filling the joint. Clean, fill and level it. Let it cure. Re-bed the caprail with something less agressive (Sikaflex).

Methacrylate would not be somewhat of a waste unless you could unbolt and separate the joint (not likely). Besides, it is expensive and has a short working time.

You are just stopping leaks, not re-inforcing the joint.

I like your advice, I believe I'll be using it when I tackle my hull/deck joint.
Thanks.

[roverhi]

Just remembered this. Had a nagging small leak from the main hatch in the companion way. Nothing I did would stop it. Finally laid some liquid LifeCaulk along the wood trim and glass joint and no more leak. Something that might work as the Liquid LifeCaulk will flow into voids in the joint caulk. West Marine also sells something from England. It's got a wierd name like Major So and So's Leak Stopper or something. There have been quite a few good reviews on this product.

[GordMay]

Originally Posted by roverhi

... West Marine also sells something from England. It's got a wierd name like Major So and So's Leak Stopper or something. There have been quite a few good reviews on this product.

Capt. Tolley's Creeping Crack Cure?
➥ Capt. Tolley's Creeping Crack Cure

[Danibug]

Thanks so much for all of the advice! We decided on 5200 and caulked the seam this past Sunday. It took 5 cartridges. Here are a few photos of the outcome with more detail on the blog.