Strip Planking wood

Discussion in 'Materials' started by Friedrich, Sep 17, 2004.

  1. Friedrich

    Friedrich Guest

    Everyone knows that Western Red Cedar is the famous wood for strip planking.
    But if you consider it is just the core of a wood/glass(or carbon or aramid)/epoxy sandwich, does we really need to use Red Cedar ?

    Which are the other wood species we can use ?

    What are the requirements for a wood to be a good candidate for stripplanking ?

    Why not use plywood strip ?

  2. duluthboats
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    duluthboats Senior Dreamer

    For canoes, kayaks, and very small boats the wood is mainly core, adding stiffness to the laminate. For this the preference is for wood that is light in weight, easy to work, and will bond well to the fabric. Another good trait for wood used in a laminate is that it doesn’t expand and contract with small changes in moisture content. If the boat is larger the longitudinal strength of the wood is probably figured in the scantlings. Plywood has less strength longitudinally than good quality wood.

  3. Ilan Voyager
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    Ilan Voyager Senior Member

    Duluth is right: plywood has a lower modulus than wood, thus less rigid.

    Also let's think a bit: strip planking is a method where the wood gives the longitudinal strength and the deflection resistance, the glass (or fiber) takes the diagonal stresses and with the resin insures the watertighness.

    Wood cost a fraction of plywood per pound, and it's a pity to take a plywood panel and to cut it in strips for less result taht simple wood.

    The north american use WRC, which is a common and avalaible wood in the States. The requisites for a wood used as core is lightness and a good ratio stiffness weight with straight grain. Resistance to rot is apreciated but not absolutely mandatory in small boats.

    A lot of pines and cedars species meet the requirements. In Europe the swedish white pine is perfect. Here in Mexico the white cypress and the tropical red cedar are very good.

    So go to see in the lumberyards... I built a small pram with pine found in a Home Mart like store at Paris, truly nice; probably a russian pine.
  4. John ilett
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    John ilett Senior Member

    Another timber to try is Pauwlonia, not as strong for weight as cedar but considerably lighter and once sheathed with the laminate I guess as good as cedar. WR cedar is 350kg m cube and pauwlonia is 275kg. It's also exactly half the price!

    A strip built timber hull will have a thinner laminate than foam with a majority of fibre orientation accross the hull whereas a foam cored hull would have thicker skins with longitudinal fibre also.

    here is some info
  5. Ilan Voyager
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    Ilan Voyager Senior Member

    Thanks Johnn for your information. I'll try to get some technical data about this wood. Maybe it's an interesting alternative for strip planking.
  6. gonzo
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    gonzo Senior Member

    In New England lobster boats are strip planked in white pine. Any wood species can be used. However, if you are going to laminate over it, a low density wood is better.
  7. Friedrich

    Friedrich Guest

    Technical Sheets

    Is anyone could send me a technical sheet with physico-mechanical values of :

    1) Western Red Cedar
    2) Paulownia
    3) Balsa

    Thanks for your help

  8. bjl_sailor
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    bjl_sailor Junior Member

    How about eastern white pine for strip planing

    I live in New england and eastern white pine is plentifull and fairly cheap. In the 'D' and better grades it is virtually knot free and extremely light and easy to work with. It rots easily but isn't what epoxy encapsulation is for? I'll need to check it's modulos of elastiscity compared to Western red Cedar.
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    D'ARTOIS Senior Member

    Wood for woodcore systems

    Western Red Cedar should be avoided in the woodcore concept.
    It burns like hell and it bonds bad when not throughly degreased.
    Therefore use Redwood. Plentyful available in the US and in Holland, where a lot of woodcore boats are built, very popular.
    It has the same weight for strength specs as Red Cedar, even a bit better, and doesnot burn!

  10. Not A Guest
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    Not A Guest Junior Member

    LVLs are made like plywood in large presses.

    Potlach Lumber will custom make plywood/LVLs upto 50' or so in length.

    I guess one could get sheets of LVL Red Cedar or perhaps something even better.

    But back to the original question ...

    You can vary the thickness of the faces relative to the thickness of the core. Each variation is a different material. Small boats are usually made with thick cores and thin faces, large boats with thin cores and thick faces. These choices are driven by economics for the most part.
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