Non-Laminated Oar Looms

Discussion in 'Boatbuilding' started by Milehog, Aug 20, 2021.

  1. Milehog
    Joined: Aug 2006
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    Milehog Clever Quip

    I have some green Douglas fir planks that have been sitting under cover for a couple years. I'd like to carve them into longish oars without laminating them.
    Is this inviting twisted and bent oars?
     
  2. wet feet
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    wet feet Senior Member

    As with anything to do with wood,there is no clear cut answer.Part of it depends on which part of the tree the pieces came from as this will have some bearing on the internal stresses that may be present.To be absolutely sure of getting the oars out my approach would be to mark a centreline and cut an oversize blank,then check to see if the centreline is still straight.If it has taken on a curve then flip the blank over and mark a new line for use with the actual pattern and you will be quite close.When working the wood,keep both sides progressing at the same rate to prevent any residual stress from bending or twisting the blade.If a bit of distortion does creep in,I doubt most users would ever notice the miniscule difference in shape or performance or you could hang some weight in the right place to distort it back to a desired level of "perfection".
     
  3. Milehog
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    Milehog Clever Quip

    That makes sense. Thanks for giving me hope for my little project.
     
  4. Kayakmarathon
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    Kayakmarathon Senior Member

    A layer of 4 oz cloth would help. Reinforce the oarlock and shaft/blade joint areas with 3-4 layers of 4 oz.
     
  5. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    If the plank was taken from dead center of the tree, just a lot of waisted wood.
    If the contains any tangential growth rings, then warpage is assured.

    Lamination uses far less wood and provides a way to optimize grain orientation.
     
  6. Milehog
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    Milehog Clever Quip

    Less wood is not an issue as this lumber is just laying around. Also I don't have a way to resaw it.
    It is plain sawn and I don't think it is heart wood.
     
  7. Blueknarr
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    Blueknarr Senior Member

    Is it all vertical grain?
    Face grain will warp.
     
  8. Milehog
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    Milehog Clever Quip

    I suspect face grain is a name for plain sawn.

    [​IMG]
     
  9. wet feet
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    wet feet Senior Member

    I don't think I would spend too much time agonising over absolute perfection.Just cut the blanks and shape them and since Culler didn't use glass,I don't see any reason to inflict it on a new pair of oars.
     
  10. Milehog
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    Milehog Clever Quip

    I plan on putting a small 3/8"ish wrap of fiberglass around the tips. Watching West Systems Epoxy videos has given the idea of bedding the glass in thickened G/flex epoxy. Belt and braces. I am conscious of weight and balance, CLC's Pete Cullerish oar plans are on the menu.
    My question is if 6 oz. cloth cut on the bias will wrap around the oar tips or should I go with 4 oz.? Inquiring minds want to know.

    Improve Wooden Paddles with G/flex - Epoxyworks
    https://www.epoxyworks.com/index.php/improve-wooden-paddles-with-gflex/


     
  11. Blueknarr
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    Blueknarr Senior Member

    Plane sawn will warp. The annular rings will straighten.
     
    Will Gilmore likes this.
  12. wet feet
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    wet feet Senior Member

    For something the size of an oar tip it wouldn't be too big a project to make a test piece and see how the glass conforms.As for warping-you may get spoon blades without having to make a big effort!Over a 4-5 inch blade width it isn't really worth getting to hung up on grain orientation.
     
  13. Milehog
    Joined: Aug 2006
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    Milehog Clever Quip

    Agreed on the test pieces, they may influence tip shape as well. I ordered supplies last night including 6oz. cloth.
    As you suggested I will cut the blanks oversize and give them a couple days to settle.
    I do wonder if you can use something to mimic resin when testing the glass' drapability. Water, oil, Vaseline, syrup etc. ?
     
  14. wet feet
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    wet feet Senior Member

    Its only about an egg cup full of resin and nothing else would be as realistic.
     

  15. Will Gilmore
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    Will Gilmore Senior Member

    I bought a cello and shortly after I unpacked it at home, the fingerboard warped up to where it touched the strings. upload_2021-8-23_22-8-30.png When I looked into how to fix a warped fingerboard, all sources said the only way to fix a warped fingerboard was to plane it out until it was flat.

    General wisdom says wood moves where it wants to and you have to work with it. Let it settle, then plane it or shape it once it's done moving.

    In the case of my cello, if I planed the fingerboard flat again, there would be no wood left at the end of the overhang.

    I covered the top face of the fingerboard with a thickly folded paper towel drenched in streaming hot water. I wrapped that in plastic wrap to keep it from drying out and strapped the board down until it bent, just a little, in the opposite direction. After a week, I checked and replaced the paper towel, it was still a little damp.

    Since I could still play the instrument with the strap in place, I continued to take it to music lessons where my music teacher had little faith in my repair plan. I gave it over a month and when I removed the strap, the plastic and paper towel, it came out straight and has been straight ever since, years later.

    The issue with flat dawn planks isn't letting them settle and then planing them flat again, it's with changing moisture content. My maple kitchen countertop is 49 inches wide. It is nearly 20 years old and in the winter, the top surface dries faster than the bottom surface and I get a half inch gap between the edge of the counter and the top of the cabinets underneath. In the Summer, it reverses and things roll off onto the floor. Flat sawn boards cup in the opposite direction from the curve of their rings, but mostly, they move in and out of their cupping. So planing it out after the initial movement won't keep it stable.

    So, you can fix warpage, to a point but cupping is harder than warp to fix. Some directions of movement are more fixable than other.

    -Will
     
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