Help with strip planking (foam core)

Discussion in 'Boatbuilding' started by jazzmd, Jun 22, 2019.

  1. jazzmd
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    jazzmd Junior Member

    A call for help...

    I'm starting the build of a Van de Stadt. The plans were changed by the designer so I could build it with foam core, instead of western red cedar. So I'll strip plank it using strips of foam core.

    My question is. Considering the fact that the foam core sheets are 2meters long, how to glue them. Is it enough to glue the sheets and glassing one of the sides before cutting the strips, or must I worry with tapered scarves before cutting the strips?

    Thanks in advance for any suggestions!
     
  2. fallguy
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    fallguy Senior Member

    Foam core is usually always butt joined with thickened resins. There are some reasons why seams are not supposed to be on or near bulkheads and probably and ISO or a Lloyd's rule on that part.
     
  3. fallguy
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    fallguy Senior Member

    As for the fitment of the panels... this depends on the hull shape.

    I can answer better when you supply that information.

    This is a picture of a single sided laminate which curved nicely. This was Gurit corecell M 12mm with a 22 oz laminate on the inside. For scale, the part taped is about 5 feet long. This glue up was followed by taping with 1708 tape over the panel.

    The hull is developable panel and the sides were built with reliefs/rebates to reduce fairing.

    1325D468-B5D2-44C3-9BA1-F9231DA28BBD.jpeg
     
  4. jazzmd
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    jazzmd Junior Member

    Dear fallguy, thank you for your (very quick) reply

    I probably didnt explain myself the best way (English is not my first language)

    My question was related to the building of the strips in foam core
    I need 12 meter strips (its a 40 ft boat). So my idea is to glue foam core sheets which are 2 meters long, probably glass one of the sides, and then cut them longitudinally to have my strips to use in planking.
    So my question is how should I glue the foam core sheets?

    Thank you

    Victor
     
  5. fallguy
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    fallguy Senior Member

    Butt joins.

    Mix cabosil and epoxy. You'll want to keep edges straight.

    Use about 2-2.5 volumes of cab to epoxy. You won't need much; start with medicine cups and mix like one ounce of epoxy total or something like 3 tablespoons.

    As for glassing one side; you are confusing me.

    How do you intend to glass the whole hull?
     
  6. fallguy
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    fallguy Senior Member

    What is the strip width?

    Hull shape round or developable?
     
  7. fallguy
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    fallguy Senior Member

    But you ought not need to build 40' long strips....

    If you avoid ending on frames; you can glue as you go a bit..

    Purchase a plastic staple gun as well. These plastic staples are a huge help for a mechanical hold while resins cure.
     
  8. fallguy
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    fallguy Senior Member

    Also, is the build over male stations or inside a female?
     
  9. jazzmd
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    jazzmd Junior Member

    Van de stadt Caribbean 40, male mold
    What I meant by glassing on one side (with unidirectional fg), was simply to have more stable strips of foam core.
    As the hull is completely planked it will be normally glassed on both sides
     
  10. fallguy
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    fallguy Senior Member

    What core type and thicness?

    Typically your core will be strong enough to just use epoxy and cabosil for the planking, use the plastic staples; they will save you lotsa headache. Gun costs 200, box of staples or two for whole job. Use epoxy and cab for those butt joins.
     
  11. fallguy
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    fallguy Senior Member

    An epoxy bonded seam is stringer than the core next to it. And the plastic staples will keep the joint true during cure.

    The plastic staple gun is always used on my build for all core joins. Gotta keep it cleaned after using.
     
  12. jazzmd
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    jazzmd Junior Member

    25mm thickness, quadraxial glassing on both sides
    can you give me an example of the staple guns?
     
  13. fallguy
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    fallguy Senior Member

  14. fallguy
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    fallguy Senior Member

    You have no need to glass a 25mm seam. The epoxy bond will be superb. How wide are the strips roughly?
     

  15. fallguy
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    fallguy Senior Member

    My staples are 6mm, but you could go to 12mm.
     
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