Wood Grains

Discussion in 'Materials' started by lewisboats, Jan 24, 2015.

  1. lewisboats
    Joined: Oct 2002
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    Location: Iowa

    lewisboats Obsessed Member

    I did a search and didn't come up with anything like what I want. I would like to get peoples' info/opinions on various grain orientations and their uses. Example... Laminating a curved Stem for my boat. In my strips I have vertical grain, flat sawn and rift sawn. The vertical grain resists bending a lot more than the flat saw (which makes sense), and the rift sawn is somewhat in between. Which is the more preferred grain orientation for the operation? I had intended to mix them up so that it ended up with more stable overall structure with no built in bias' in any given direction.

    When buying wood... say you get a 2x4 flat sawn with nice straight grain... do you have a 4x2 with nice vertical grain or is there inherently something different in the cutting process that changes things?

    If you substitute rift sawn for vertical grain... what are the trade offs? Is it going to be significantly weaker or not so much?

    Is it better to use flat sawn when the main stresses are along the line of the grain ie. side to side rather than vertically through the thickness of the piece.

    I know the answers (or think I do) to most of these questions but perhaps there are others who will refer to this thread for answers to their questions.

    Also, if there are others with other questions about wood grain, structure and using it the best way, please feel free to ask here so we can get a nice go to thread for this subject... sort of a consolidation of information.

    Thanks for your input.
     
  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Your assumptions are correct, though when laminating a stem that will be brightly finished, I tend to use quarter sawn, so the grain lines run in the direction of the stem on all three visible sides. In fact, if I want to get real anal about it, I'll rip a piece for laminate stock, but with witness marks on one edge, so I can arrange the laminate stack in roughly the same position it was when a solid piece. This aligns the grain lines somewhat and makes it look more like it was a grown crook. It's important to get tight grained stock for this approach to look good.
     
  3. lewisboats
    Joined: Oct 2002
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    Location: Iowa

    lewisboats Obsessed Member

    If you are using rift sawn... I assume you alternate the angle with each course? I had thought to go Vertical, Rift, Flat then Rift (opposite orientation), then repeat as needed. I would leave the outer lamination as vertical grain in whichever case, inside face of inner stem or outside face of outer stem.
     
  4. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    If interested in strength and stiffness, I'll alternate the grain pattern, but if finished bright, I'll leave the laminate stack, just as it comes off the original piece I ripped it from, realigning during assembly in the laminate jig. This produces the prettiest grain pattern and if the grain is tight, almost looks as if it's cut from one big hunk of whatever.
     

  5. lewisboats
    Joined: Oct 2002
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    Location: Iowa

    lewisboats Obsessed Member

    Pretty is out because each of the laminations came from a different piece of lumber. I made them from T&G Flooring. Kind of expensive but they really blew away the quality of the other available wood as far a grain straightness and clarity.
     
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