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Re: Plywood checking on Brucesboat

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  • prairiedog2332
    I would have to agree, but that would incur one heck of a lot work, especially if you looking at another build! One fellow I know of who actually lives in CO
    Message 1 of 15 , Jun 22, 2013
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      I would have to agree, but that would incur one heck of a lot work,
      especially if you looking at another build!

      One fellow I know of who actually lives in CO is John Kolb who finished
      the interior of an open hull with truck box liner. Might be worth trying
      to contact him for his thoughts?

      http://www.kolbsadventures.com/boatbuilding_index.htm
      <http://www.kolbsadventures.com/boatbuilding_index.htm>

      http://www.durabakcompany.com/marine.htm
      <http://www.durabakcompany.com/marine.htm>

      Another fellow finished the exterior of his fir plywood motorboat hull
      with a brand of exterior acrylic water based house paint to which he
      added milled glass and silica as a filler. Last I heard it had not
      checked after a couple years of usage. But I have to search my files for
      the paint brand and type he claims works best. I think a high-build
      undercoat actually, then a finish coat of choice over. Plan on trying
      that myself as all you just have to do is rough up the existing paint if
      it is already acrylic. I think you folks down south refer to it as
      "latex" paint, even though it has no latex in it?

      http://www.duckworksbbs.com/supplies/additives/milled/index.htm
      <http://www.duckworksbbs.com/supplies/additives/milled/index.htm>

      Nels




      --- In Michalak@yahoogroups.com, Martin Houston wrote:
      >
      > Would say yes, sand it good & glass with epoxy resin & cloth.
      >




      [Non-text portions of this message have been removed]
    • porneaux
      Thanks everyone for the information and advice on plywood checking. Just got back from an overnighter on the Missouri river with the Brucesboat and a buddy.
      Message 2 of 15 , Jun 24, 2013
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        Thanks everyone for the information and advice on plywood checking.

        Just got back from an overnighter on the Missouri river with the Brucesboat and a buddy. 25 mph winds blowing against the currrent made for some nasty breakers in the sections parallel to the wind. Buried the bow into "brown" water several times and finally retreated to a lee shore and set camp.

        In the really rough stuff I was well beyond my comfort zone and probably near the boat's limit, but have to say it performed admirably. She stayed pointed where I steered, the pointy bow didn't pound, and the boat didn't flex. No big water crashing over the bow when burried into the back of a crest.

        Looks like my first boatbuiliding project should have been "Build a place to store the finished boat(s). Because that isn't feasible in the short term, and because I love my Brucesboat, I'm going to sand the checks down and epoxy/glass-tape the area. Will be my early season ritual. Will eventually have a glassed interior!

        Thanks again for the information.

        Brian Nimmo



        --- In Michalak@yahoogroups.com, "prairiedog2332" <nelsarv@...> wrote:
        >
        > I would have to agree, but that would incur one heck of a lot work,
        > especially if you looking at another build!
        >
        > One fellow I know of who actually lives in CO is John Kolb who finished
        > the interior of an open hull with truck box liner. Might be worth trying
        > to contact him for his thoughts?
        >
        > http://www.kolbsadventures.com/boatbuilding_index.htm
        > <http://www.kolbsadventures.com/boatbuilding_index.htm>
        >
        > http://www.durabakcompany.com/marine.htm
        > <http://www.durabakcompany.com/marine.htm>
        >
        > Another fellow finished the exterior of his fir plywood motorboat hull
        > with a brand of exterior acrylic water based house paint to which he
        > added milled glass and silica as a filler. Last I heard it had not
        > checked after a couple years of usage. But I have to search my files for
        > the paint brand and type he claims works best. I think a high-build
        > undercoat actually, then a finish coat of choice over. Plan on trying
        > that myself as all you just have to do is rough up the existing paint if
        > it is already acrylic. I think you folks down south refer to it as
        > "latex" paint, even though it has no latex in it?
        >
        > http://www.duckworksbbs.com/supplies/additives/milled/index.htm
        > <http://www.duckworksbbs.com/supplies/additives/milled/index.htm>
        >
        > Nels
        >
        >
        >
        >
        > --- In Michalak@yahoogroups.com, Martin Houston wrote:
        > >
        > > Would say yes, sand it good & glass with epoxy resin & cloth.
        > >
        >
        >
        >
        >
        > [Non-text portions of this message have been removed]
        >
      • Crandall, Chris S.
        In short, epoxy painted over plywood does NOT stop checking, although it slows it down some. To prevent checking, there are two choices: 1) Use a plywood that
        Message 3 of 15 , Jun 24, 2013
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          In short, epoxy painted over plywood does NOT stop checking, although it slows it down some. To prevent checking, there are two choices:

          1) Use a plywood that is not prone to checking. This is the pricy stuff, made overseas, and usually involves cutting down some of the rainforest.

          2) Use fiberglass cloth with that epoxy.

          Checking comes from moisture cycling. The earlywood and latewood in douglas fir (in particular) expand and contract and notably different rates. This, in plywood veneers, leads to tearing of the fibers (checking) with repeated cycling. Plywood kept at constant moisture doesn't check--but what boat doesn't moisture cycle? (Boats kept in museums, perhaps.) Since tropical rainforests have more constant climate/seasons, there is not the pronounced earlywood/latewood structure--that's the rings you see in the wood [try counting rings in teak or iroko]--and so the checking is less of a problem.

          So the painting on of epoxy slows down, but as you've learned, does not prevent checking. Since you're not going to replace the plywood on your boat, you have a few options:

          1) Sand, sand, sand to bare wood, apply a lightweight fiberglass cloth (4 oz is fine, 2oz might be OK), set in epoxy.

          2) Sand some, and patch. This is the easiest, and it isn't bad. Sand it down as much as you can stand, and then patch with epoxy and filler. I have come to like WEST System Microlight filler. It sands very, very easily. I will never go back to phenolic microballoons. (It's also a pleasing color, which the maroon balloons were not.)

          3) Paint another coat over it, and recognize that checking is only a problem for you if they trap moisture. If you can keep the boat dry, your problems are primarily cosmetic.

          And remember to enjoy your boat as it is, and to plan another build.

          -Chris
        • Joseph Stromski
          I agree with everything below, except the pricy stuff comment. My AF4 used 1/2 MDO for the bottom, and 1/4 baltic birch premium underlayment for the side
          Message 4 of 15 , Jun 24, 2013
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            I agree with everything below, except the "pricy stuff" comment. My AF4 used 1/2" MDO for the bottom, and 1/4" baltic birch premium underlayment for the side panels. Both obtained cheaply from my local big box store (Menards). The MDO hasn't/won't check due the the facing on it, and the birch shows no indication of checking with only an epoxy spit coat, no glass, after nearly 4 years. 

            Best,
            Joe


            ________________________________
            From: "Crandall, Chris S." <crandall@...>
            To: "Michalak@yahoogroups.com" <Michalak@yahoogroups.com>
            Sent: Monday, June 24, 2013 9:49 AM
            Subject: [Michalak] Re: Plywood checking on Brucesboat



             
            In short, epoxy painted over plywood does NOT stop checking, although it slows it down some. To prevent checking, there are two choices:

            1) Use a plywood that is not prone to checking. This is the pricy stuff, made overseas, and usually involves cutting down some of the rainforest.

            2) Use fiberglass cloth with that epoxy.

            Checking comes from moisture cycling. The earlywood and latewood in douglas fir (in particular) expand and contract and notably different rates. This, in plywood veneers, leads to tearing of the fibers (checking) with repeated cycling. Plywood kept at constant moisture doesn't check--but what boat doesn't moisture cycle? (Boats kept in museums, perhaps.) Since tropical rainforests have more constant climate/seasons, there is not the pronounced earlywood/latewood structure--that's the rings you see in the wood [try counting rings in teak or iroko]--and so the checking is less of a problem.

            So the painting on of epoxy slows down, but as you've learned, does not prevent checking. Since you're not going to replace the plywood on your boat, you have a few options:

            1) Sand, sand, sand to bare wood, apply a lightweight fiberglass cloth (4 oz is fine, 2oz might be OK), set in epoxy.

            2) Sand some, and patch. This is the easiest, and it isn't bad. Sand it down as much as you can stand, and then patch with epoxy and filler. I have come to like WEST System Microlight filler. It sands very, very easily. I will never go back to phenolic microballoons. (It's also a pleasing color, which the maroon balloons were not.)

            3) Paint another coat over it, and recognize that checking is only a problem for you if they trap moisture. If you can keep the boat dry, your problems are primarily cosmetic.

            And remember to enjoy your boat as it is, and to plan another build.

            -Chris




            [Non-text portions of this message have been removed]
          • Brian Nimmo
            Hi Joe, Does the MDO have the nice facing on both sides? Does the facing adhere to epoxy like normal plywood? How do you store your AF4 during long periods
            Message 5 of 15 , Jun 24, 2013
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              Hi Joe,

              Does the MDO have the nice facing on both sides? Does the facing adhere to epoxy like normal plywood? How do you store your AF4 during long periods of non-use?

              Thanks.

              Brian


              To: Michalak@yahoogroups.com
              From: j.stromski@...
              Date: Mon, 24 Jun 2013 09:12:56 -0700
              Subject: Re: [Michalak] Re: Plywood checking on Brucesboat


























              I agree with everything below, except the "pricy stuff" comment. My AF4 used 1/2" MDO for the bottom, and 1/4" baltic birch premium underlayment for the side panels. Both obtained cheaply from my local big box store (Menards). The MDO hasn't/won't check due the the facing on it, and the birch shows no indication of checking with only an epoxy spit coat, no glass, after nearly 4 years.



              Best,

              Joe



              ________________________________

              From: "Crandall, Chris S." <crandall@...>

              To: "Michalak@yahoogroups.com" <Michalak@yahoogroups.com>

              Sent: Monday, June 24, 2013 9:49 AM

              Subject: [Michalak] Re: Plywood checking on Brucesboat







              In short, epoxy painted over plywood does NOT stop checking, although it slows it down some. To prevent checking, there are two choices:



              1) Use a plywood that is not prone to checking. This is the pricy stuff, made overseas, and usually involves cutting down some of the rainforest.



              2) Use fiberglass cloth with that epoxy.



              Checking comes from moisture cycling. The earlywood and latewood in douglas fir (in particular) expand and contract and notably different rates. This, in plywood veneers, leads to tearing of the fibers (checking) with repeated cycling. Plywood kept at constant moisture doesn't check--but what boat doesn't moisture cycle? (Boats kept in museums, perhaps.) Since tropical rainforests have more constant climate/seasons, there is not the pronounced earlywood/latewood structure--that's the rings you see in the wood [try counting rings in teak or iroko]--and so the checking is less of a problem.



              So the painting on of epoxy slows down, but as you've learned, does not prevent checking. Since you're not going to replace the plywood on your boat, you have a few options:



              1) Sand, sand, sand to bare wood, apply a lightweight fiberglass cloth (4 oz is fine, 2oz might be OK), set in epoxy.



              2) Sand some, and patch. This is the easiest, and it isn't bad. Sand it down as much as you can stand, and then patch with epoxy and filler. I have come to like WEST System Microlight filler. It sands very, very easily. I will never go back to phenolic microballoons. (It's also a pleasing color, which the maroon balloons were not.)



              3) Paint another coat over it, and recognize that checking is only a problem for you if they trap moisture. If you can keep the boat dry, your problems are primarily cosmetic.



              And remember to enjoy your boat as it is, and to plan another build.



              -Chris



              [Non-text portions of this message have been removed]



















              [Non-text portions of this message have been removed]
            • porneaux
              Great information Chris, thank you. I just returned from a trip enjoying my Bboat just as it is (checking and all), and am 30 hours into the next build - an
              Message 6 of 15 , Jun 24, 2013
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                Great information Chris, thank you.

                I just returned from a trip enjoying my Bboat just as it is (checking and all), and am 30 hours into the next build - an AF4.

                --- In Michalak@yahoogroups.com, "Crandall, Chris S." <crandall@...> wrote:
                >
                > And remember to enjoy your boat as it is, and to plan another build.
                >
                > -Chris
                >
              • Joseph Stromski
                The MDO I used had non-primed facing on 2 sides. There s quite a few different varieties of it out there, however. Primed, non-primed, etc.  I handled it no
                Message 7 of 15 , Jun 24, 2013
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                  The MDO I used had non-primed facing on 2 sides. There's quite a few different varieties of it out there, however. Primed, non-primed, etc.  I handled it no differently than regular plywood. The boat is garaged. 

                  Best,
                  Joe


                  ________________________________
                  From: Brian Nimmo <owwin@...>
                  To: "Michalak@yahoogroups.com" <michalak@yahoogroups.com>
                  Sent: Monday, June 24, 2013 11:23 AM
                  Subject: RE: [Michalak] Re: Plywood checking on Brucesboat


                  Hi Joe,

                  Does the MDO have the nice facing on both sides?  Does the facing adhere to epoxy like normal plywood?  How do you store your AF4 during long periods of non-use?

                  Thanks.

                  Brian


                  To: Michalak@yahoogroups.com
                  From: j.stromski@...
                  Date: Mon, 24 Jun 2013 09:12:56 -0700
                  Subject: Re: [Michalak] Re: Plywood checking on Brucesboat




















                   


                     
                       
                       
                        I agree with everything below, except the "pricy stuff" comment. My AF4 used 1/2" MDO for the bottom, and 1/4" baltic birch premium underlayment for the side panels. Both obtained cheaply from my local big box store (Menards). The MDO hasn't/won't check due the the facing on it, and the birch shows no indication of checking with only an epoxy spit coat, no glass, after nearly 4 years.



                  Best,

                  Joe



                  ________________________________

                  From: "Crandall, Chris S." <crandall@...>

                  To: "Michalak@yahoogroups.com" <Michalak@yahoogroups.com>

                  Sent: Monday, June 24, 2013 9:49 AM

                  Subject: [Michalak] Re: Plywood checking on Brucesboat





                   

                  In short, epoxy painted over plywood does NOT stop checking, although it slows it down some. To prevent checking, there are two choices:



                  1) Use a plywood that is not prone to checking. This is the pricy stuff, made overseas, and usually involves cutting down some of the rainforest.



                  2) Use fiberglass cloth with that epoxy.



                  Checking comes from moisture cycling. The earlywood and latewood in douglas fir (in particular) expand and contract and notably different rates. This, in plywood veneers, leads to tearing of the fibers (checking) with repeated cycling. Plywood kept at constant moisture doesn't check--but what boat doesn't moisture cycle? (Boats kept in museums, perhaps.) Since tropical rainforests have more constant climate/seasons, there is not the pronounced earlywood/latewood structure--that's the rings you see in the wood [try counting rings in teak or iroko]--and so the checking is less of a problem.



                  So the painting on of epoxy slows down, but as you've learned, does not prevent checking. Since you're not going to replace the plywood on your boat, you have a few options:



                  1) Sand, sand, sand to bare wood, apply a lightweight fiberglass cloth (4 oz is fine, 2oz might be OK), set in epoxy.



                  2) Sand some, and patch. This is the easiest, and it isn't bad. Sand it down as much as you can stand, and then patch with epoxy and filler. I have come to like WEST System Microlight filler. It sands very, very easily. I will never go back to phenolic microballoons. (It's also a pleasing color, which the maroon balloons were not.)



                  3) Paint another coat over it, and recognize that checking is only a problem for you if they trap moisture. If you can keep the boat dry, your problems are primarily cosmetic.



                  And remember to enjoy your boat as it is, and to plan another build.



                  -Chris



                  [Non-text portions of this message have been removed]






                     
                     

                     
                     






                                           

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