Sealing internal corners - choosing a sealant.

Discussion in 'Boatbuilding' started by hospadar, Jun 25, 2012.

  1. hospadar
    Joined: Apr 2011
    Posts: 63
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    Location: Michigan

    hospadar Junior Member

    On the little boat I'm building, I'm wondering about how to seal the inside corners. It's a chine logged boat held together with PL premium and ringnails. Because of this, some of the internal corners don't meet quite perfectly (where the chine log sat a little proud of the plywood, where the aftwards-facing side of the front deck/airbox doesn't perfectly fit the inside airbox sides, etc).

    It's nothing major, it's not going to affect seaworthiness, but it's
    a) unsightly
    b) I'm concerned the little corners will become a trap for moisture and rot.

    I'm wondering if there's a good way to seal these other than a stitch-and-glue style epoxy/fiberglass fillet. I'm not really interested in going full bore on these since they aren't structural, I just need to seal them off.

    I was thinking:
    a) Epoxy fillet without glass - seems like it would crack. Also kind of a hassle. The whole idea here is to just buy a tube of some stuff and be done with it.

    b) Silicone: I'm not real crazy about silicone, but maybe it would be OK

    c) Lexel: Non-silicone sealant. Supposedly paintable, doesn't seem to dry quite as firm as silicone, but maybe that's a good thing.

    d) Some kind of roofing sealant: I'm not sure exactly which one I'd use, it'd need to not be sticky like tar, but roof sealant is probably the most elastic and durable of these choices.

    The boat's not going in saltwater, and it's not going to be outside or wet all the time, but of course durability still is desirable
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    A paint grade caulk would be the best for finishing. Lexel or something similar would be my choice.
  3. lewisboats
    Joined: Oct 2002
    Posts: 2,329
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    Location: Iowa

    lewisboats Obsessed Member

    better that it would be going in salt water...fresh is the stuff that causes rot. There is a new PL premium out that has fillers in it...VERY thick and hard to gun. I used it as a glue but I like the thinner stuff better for that. However...I think it would be perfect as a filleting material as it doesn't seem to foam up as much as the thinner stuff. I kind of did this with the squeeze out when I put my external chine logs on my boat and it worked pretty good.
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