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warped planking

Discussion in 'Wood and Canvas' started by Rollin Thurlow, Jan 23, 2021.

  1. Rollin Thurlow

    Rollin Thurlow member since 1980

  2. OP
    OP
    Rollin Thurlow

    Rollin Thurlow member since 1980

    I had a good example of planking warping on my bench and thought some of you would be interested in this observation.
    This is an example of how a piece of flat sawn planking will warp when it gets wet. You can see the end grain and how the edges curve up opposite of the curve of the grain. At first glance it curves opposite of what you would normally think it would curve. When the plank dries out it will shrink just a bit as it flattens out.
    If your using flat sawn planking its good to take this natural warping tendency in to account when installing the planking. Laying the plank one way and the curve will follow the hull. Lay the plank the other way and its easy to see how the edges can lift and either create a ridge in the canvas and/[] or the wood will split where the edge tacks are trying to hold it down.
    When the planking gets wet and dries, the flat sawn planking will swell/shrink in width. With the quartersawn planking it will swell/shrink in thickness which can lift the heads of the tacks above the surface of the wood if the tacks have not been properly clinched and countersunk.
    Its good to take this all in account when trying to make a hull that will stay smooth.
     

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  3. Dan Miller

    Dan Miller cranky canoeist Staff Member

    A nice example, Rollin.

    I wouldn't be surprised that the builders of Peterborough-style wide-board canoes used this behavior to their advantage to get the planks to conform to the hull shape.
     

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