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Steam bending softwoods

Discussion in 'Birchbarks, Dugouts and Primitive Craft' started by HarryA, Sep 4, 2007.

  1. HarryA

    HarryA woodwrecker

    Are there any tables that give the steam bending qualities
    of softwoods?

    I gather softer woods like cedar, pine, poplar, and basswood
    are much more difficult to bend compared to hardwoods.

    I wonder how basswood compares to white cedar
    for canoe ribs for example? Good quaility basswood is readily
    available compared to white cedar.

    This site shows the bending qualities of hardwoods:
    http://www.solidwoodbending.net/wb-species.htm
     
  2. Dan Miller

    Dan Miller cranky canoeist Staff Member

    Most of your better books about boat building discuss bending properties of various woods.

    You can't generalize that hardwoods bend well and softwoods don't - there are some hardwoods that don't bend well, and some softwoods that bend very well. There is great variation even within species on a tree-to-tree basis.

    In addition to considering bending properties, you need to consider other factors in choosing your woods - strength, rot resistance, etc. The combination of excellent bending properties and rot resistance is what makes northern white cedar one of the premier canoe building woods. Red oak bends extremely well, but its lack of rot resistance makes it generally unsuitable for boatbuilding.

    Basswood has little resistance against rot. It can be shaped with hot water, as demonstrated by its use in wide-board canoes. I have never heard of it being used for ribs, it may not bend well enough for that. Since you have a ready supply, it would be easy enough to do the experiment.
     
  3. OP
    OP
    HarryA

    HarryA woodwrecker

    More on steam bending.

    Good point about the rot resistance of
    various woods.

    It's interesting to see in Adney how they
    made the old form of stem-pieces; that took
    some careful bending!

    In Gidmark's "Building a Birchbark Canoe"
    he writes of how many extra ribs were required
    in building a canoe ..One builder once broke
    twenty-two ribs in building a canoe.

    Also he writes how builders often bend two
    ribs at once. That is similar to using a metal
    strap around wood when bending it for snowshoes?
    It moves the tension to the outer most one away
    from the inner one that is getting bend the most
    (putting it under compression rather then tension)
    I would think.
     
  4. Rollin Thurlow

    Rollin Thurlow member since 1980

    Technically, I belive the poplar and basswood would be classified as hardwoods even if their wood is really fairly "soft". I might be wrong on this, not having checked it out, but for this discussion it doesn't really matter. They both should bend farily well. We know the cedar bends well when it is thin as in most canoe uses but when it gets thicker such as a 1" thick board for a Morris stem, it is difficult to bend. The pine bends like crap and I rather eat boiled shoe leather than have to steam bend pine of any real thickness!
    Rollin
     
  5. OP
    OP
    HarryA

    HarryA woodwrecker

    Softwoods

    Good points. As I recall from the directions on a can of Miniwax
    primer/conditioner to consider any wood that you can dent
    with your thumbnail to be soft. I think that is a good guide.

    I am planning on building a birch bark like canoe this winter.
    As I have standing basswood, ash, and cherry I will
    use basswood for lining then ash for ribs and trim.
    And a few coats of marine varnish on both.

    Birchbark or birch bark? Searching on Yahoo yields 265,000
    hits for birchbark and 1,780,000 for birch bark plus the Firefox
    browser spell checker doesn't like "birchbark.
     
  6. Andy Hutyera

    Andy Hutyera The Red Canoe Guy - Life Member

  7. Rob Stevens

    Rob Stevens Wooden Canoes are in the Blood

    From a foresters point of view, anytree with leaves is a hardwood, any with needles a softwood -with a few complicators like birch, tamarack,..

    [/QUOTE=I am planning on building a birch bark like canoe this winter.
    As I have standing basswood, ash, and cherry I will
    use basswood for lining then ash for ribs and trim.
    And a few coats of marine varnish on both.

    [/QUOTE]
    If you build completely of cedar you won't need to use any varnish as it will be naturally rot resistant. Basswood rots quickly. If used as planking, water will surely get trapped between it and the birchbark sheathing.

    Mind you, cherry is a pretty wood, though not particularly rot resistant.
     
  8. OP
    OP
    HarryA

    HarryA woodwrecker

    cedar and basswoods

    thanks Andy; that is a very useful article.

    Rob,
    Your comments are very good but:

    Here is why I have a problem with the evergreen and
    deciduous argument:

    "Despite being very soft, balsa is classified
    as a hardwood, the softest commercial hardwood."
    from Wikipedia

    for Cedar versus Basswood; I have no idea were to
    find white cedar but I can grab the chainsaw and
    go about 200 ft up the hill and get basswood.
    So for me basswood and marine varnish are more
    practical.
     
  9. ElectricSquid

    ElectricSquid Wannabee Canoe Builder

    Thanks, I'll be reading that tomorrow. Looks like it goes in depth about it.
     
  10. beaver

    beaver Birchbark CanoeingBuilder

    You guys are barking up the wrong tree here. The wood to use is and has always been white cedar (Arbor Vitae, The Tree of Life)


     
  11. ElectricSquid

    ElectricSquid Wannabee Canoe Builder

    How much of a difference is there between Western Red Cedar and White Cedar?
     
  12. ElectricSquid

    ElectricSquid Wannabee Canoe Builder

    According to that article, "only air-dried wood should be used".
    They say "kiln-dried wood must not be used; the lignin in the wood has been permanently set during the hot, dry kilning process. No amount of steaming or soaking will weaken the lignin bond sufficiently for successful bending."

    Just a little further on, the article states "Softwoods do not bend well and should be avoided."

    I personally, have never steam bent wood before, so someone give me a clue as to wheither this info is absolutly true.

    ...and what does that mean for me, some yahoo in Florida that's trying to build a boat from Western Red Cedar that's been
    kiln dried to 8-12% moisture?
    ( that's about all that's readily available ... for very little cost [cough] free [cough] [​IMG] )
     
  13. Dave Wermuth

    Dave Wermuth Who hid my paddle?

    E squid

    as I recall you plan to build a stripper? In that case, it doesn't matter. No problem.

    Adn about the dif between red or white. I find white stronger and more flexible. Red comes in long lengths but is more brittle. Makes for nice contrast if white is ribs and red is planking.
     
  14. ElectricSquid

    ElectricSquid Wannabee Canoe Builder

    Thanks, that was helpful :)
     

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