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Re: [bolger] Re: how urgent it is to seal up my new centerboard?

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  • Jay Bazuzi
    A followup: I put 3 layers of epoxy on today, with 3-4 hours between coats, because that how my schedule worked out. I originally planned to put only 2 coats,
    Message 1 of 9 , Jul 6, 2009
      A followup: I put 3 layers of epoxy on today, with 3-4 hours between coats, because that how my schedule worked out.  

      I originally planned to put only 2 coats, but once we were all set up it was very easy to apply, so we went ahead with a  3rd.  The end grain at the shaped edges was particularly thirsty, so I'm glad I added that extra coat.  I considered a 4th coat, but I want to save some for the next step, and buying another can of epoxy would mean most of it just sitting in the garage, waiting for trouble.

      I hung the board up by 2 corners.  This mean I could get the edges and faces in one go.  I figured that having continuous epoxy around the edges would put strength where it mattered.  

      After it cures I'll lay it down on the sawhorses to fill the gouges and the groove at the edge of the lead sinkweight (scuffing for a good bond, of course).

      -Jay
      Port Townsend, WA


      On Mon, Jul 6, 2009 at 9:06 AM, Jay Bazuzi <jay@...> wrote:
      Thanks for your advice, Gary and David.  I have decided to seal the board before trying it out.  I bought some epoxy yesterday and did some test coats on scraps of the same wood that the centerboard is made of. Today I will buy some disposable roller covers and stuff, and start painting on the epoxy.

      In last night's tests, it took about 2 hours for the epoxy to reach the tacky gel stage.  This is WEST with "Fast" hardener.  I guess the cool evening weather slowed it down a lot.  My first time using "real" epoxy, e.g. not a two-barreled syringe for fixing things around the house.

      I like that idea of the leading-edge polyester rope.  The older centerboard took a beating at the lowest point, and I was worried about it there.  When shaping the edges, I left a little more material right there, so it would be stronger.  But had I known, I would have gone for the rope idea.  Next time :-)

      -Jay



      On Sun, Jul 5, 2009 at 8:22 PM, gbship <gbship@...> wrote:


      If you take it out in salt water, make sure your rinse and dry it before sealing. The salt in the board will retain moisture and probably isn't good for epoxy adhesion even if it's dry.

      Sounds like your board is one piece and not laminated of 2 or 3 layers of thinner ply. That makes it more prone to warping, and the longer it's unprotected the more likely it is to warp (and the surface to check or split). Also, in shaping the leading and trailing edges, you've exposed a lot more end grain than normal and the unprotected board will be quicker to soak up a lot of water.

      I'd at least do the epoxy sealing before using it.

      BTW, the best way to protect the leading edge of a leeboard or centerboard is to plane it flat and then attach and fair in a piece of polyester rope thoroughly soaked in epoxy. When the epoxy in the rope cures, it's like casting a stone in place. It will stand up to all sorts of abuse, short of dragging it on the pavement when you tow the boat home on the trailer (don't ask me how I know this . . .).

      Gary



      --- In bolger@yahoogroups.com, Jay Bazuzi <jay@...> wrote:
      >
      > I have been building a new centerboard for my Bobcat. (The old one was
      > warped, and was hard to raise and lower.)
      >
      > I have shaped a piece of 3/4" marine plywood: cut it, beveled the water foil
      > edges, drilled the holes, cut the pivot hook. Then I glued & screwed the
      > brass plates at the pivot hook, and poured the lead sinkweight.
      >
      > The instructions I have are to brush on 2 layers of epoxy, and then a couple
      > layers of marine enamel paint.
      >
      > I have some questions about how critical it is to put the finish on the
      > centerboard right away.
      >
      > - Can I take the bare centerboard out for a sea trial? Just an hour, in
      > salt water.
      >
      > - Can I leave it bare and sail it for the rest of the summer, then dry &
      > finish it in the fall?
      >
      > - If I don't ever finish it, how bad is that?
      >
      >
      > -Jay
      >



    • Jay Bazuzi
      Curious: how well would a boat sauce (teak oil, varnish, pine tar) work on a plywood centerboard? Could it be applied to the portion that is visible when
      Message 2 of 9 , Jul 13, 2009
        Curious: how well would a "boat sauce" (teak oil, varnish, pine tar) work on a plywood centerboard?  Could it be applied to the portion that is visible when the centerboard is fully raised, while epoxying the rest of the board?

        -Jay


        On Mon, Jul 6, 2009 at 7:17 PM, Jay Bazuzi <jay@...> wrote:
        A followup: I put 3 layers of epoxy on today, with 3-4 hours between coats, because that how my schedule worked out.  

        I originally planned to put only 2 coats, but once we were all set up it was very easy to apply, so we went ahead with a  3rd.  The end grain at the shaped edges was particularly thirsty, so I'm glad I added that extra coat.  I considered a 4th coat, but I want to save some for the next step, and buying another can of epoxy would mean most of it just sitting in the garage, waiting for trouble.

        I hung the board up by 2 corners.  This mean I could get the edges and faces in one go.  I figured that having continuous epoxy around the edges would put strength where it mattered.  

        After it cures I'll lay it down on the sawhorses to fill the gouges and the groove at the edge of the lead sinkweight (scuffing for a good bond, of course).

        -Jay
        Port Townsend, WA


        On Mon, Jul 6, 2009 at 9:06 AM, Jay Bazuzi <jay@...> wrote:
        Thanks for your advice, Gary and David.  I have decided to seal the board before trying it out.  I bought some epoxy yesterday and did some test coats on scraps of the same wood that the centerboard is made of. Today I will buy some disposable roller covers and stuff, and start painting on the epoxy.

        In last night's tests, it took about 2 hours for the epoxy to reach the tacky gel stage.  This is WEST with "Fast" hardener.  I guess the cool evening weather slowed it down a lot.  My first time using "real" epoxy, e.g. not a two-barreled syringe for fixing things around the house.

        I like that idea of the leading-edge polyester rope.  The older centerboard took a beating at the lowest point, and I was worried about it there.  When shaping the edges, I left a little more material right there, so it would be stronger.  But had I known, I would have gone for the rope idea.  Next time :-)

        -Jay



        On Sun, Jul 5, 2009 at 8:22 PM, gbship <gbship@...> wrote:


        If you take it out in salt water, make sure your rinse and dry it before sealing. The salt in the board will retain moisture and probably isn't good for epoxy adhesion even if it's dry.

        Sounds like your board is one piece and not laminated of 2 or 3 layers of thinner ply. That makes it more prone to warping, and the longer it's unprotected the more likely it is to warp (and the surface to check or split). Also, in shaping the leading and trailing edges, you've exposed a lot more end grain than normal and the unprotected board will be quicker to soak up a lot of water.

        I'd at least do the epoxy sealing before using it.

        BTW, the best way to protect the leading edge of a leeboard or centerboard is to plane it flat and then attach and fair in a piece of polyester rope thoroughly soaked in epoxy. When the epoxy in the rope cures, it's like casting a stone in place. It will stand up to all sorts of abuse, short of dragging it on the pavement when you tow the boat home on the trailer (don't ask me how I know this . . .).

        Gary



        --- In bolger@yahoogroups.com, Jay Bazuzi <jay@...> wrote:
        >
        > I have been building a new centerboard for my Bobcat. (The old one was
        > warped, and was hard to raise and lower.)
        >
        > I have shaped a piece of 3/4" marine plywood: cut it, beveled the water foil
        > edges, drilled the holes, cut the pivot hook. Then I glued & screwed the
        > brass plates at the pivot hook, and poured the lead sinkweight.
        >
        > The instructions I have are to brush on 2 layers of epoxy, and then a couple
        > layers of marine enamel paint.
        >
        > I have some questions about how critical it is to put the finish on the
        > centerboard right away.
        >
        > - Can I take the bare centerboard out for a sea trial? Just an hour, in
        > salt water.
        >
        > - Can I leave it bare and sail it for the rest of the summer, then dry &
        > finish it in the fall?
        >
        > - If I don't ever finish it, how bad is that?
        >
        >
        > -Jay
        >




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