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  1. #1
    Member
    Join Date
    Nov 2005
    Location
    Tucson, AZ., USA.
    Posts
    1

    How can I flatten cupped boards?

    I planed a bunch of Maple down to 1/2" for a project. It sat on the bench for a week (in dry Arizona), and when I checked it again, it had all warped or cupped. How can I flatten the boards so I can use them? Not new to woodworking, but new to planing and precision woodworking......Olburro

  2. #2
    Member
    Join Date
    Nov 2001
    Location
    Gaylord, Michigan.
    Posts
    4,974

    RE: How can I flatten cupped boards?

    Welcome to the Forum!!! What do we call you for "short"?

    Any who, sounds like either you thicknessed these boards before they reached equilibrium and/or you only thicknessed one side, it's best to take off equal amounts from both faces.

    Do you have any projects that call for 1/4qtr Maple? At this juncture I seriously doubt that even "moisturizing" the concave face would solve your problem.

    Dano

  3. #3
    Member
    Join Date
    Sep 2004
    Location
    Maine, USA.
    Posts
    6,010

    RE: How can I flatten cupped boards?

    Sometimes a piece of wood just doesn't want to cooperate. Save it for another project where you can make it work for you.

  4. #4
    Member
    Join Date
    Nov 2005
    Location
    Louisville, KY, USA.
    Posts
    556

    RE: How can I flatten cupped boards?

    Well if it cupped because one side dried out more than the other side
    you may want to try something I read about.
    The article said you could dampen the side that was exposed and
    store it upside down until it flattened out because the other
    side would catch up. But once flattened you need to sticker it
    under weight until it equalized again.
    I don't know if that works, only read it.
    If it does, let us know. I'd be curious to see.

    I use to have the same problem with wood before I got it shop
    acclimated, now that I have my inventory built up to the point
    where I only use older wood I don't have that problem.
    I have done exactly what you did to show the stability
    of my wood in a comparrison test.
    I flatten a board on the jointer, plane it, then
    lay it face down on a smooth surface for a couple of days.
    If it stays flat and true then the wood is dry and stable enough
    for me to use. If it doesn't then it's not aged enough.
    I have used kiln dried "store bought" that won't pass that test,
    but all my older "air dried" (inside stored) wood does.
    There's no substitute for time.


    Jim C.

  5. #5
    Member
    Join Date
    Dec 1969
    Location
    Ida Grove, Ia.
    Posts
    928

    RE: How can I flatten cupped boards?

    I think the key to your problem is "it layed on the bench for a week ".Even if you planed equally off both sides only one freshly planed side was exposed to the nice dry Arizona air do to laying it flat on the bench.It should come out of it if you follow Jims advice if not another lesson learned.Been there done that.:+ Good luck.

  6. #6
    Member
    Join Date
    Dec 1969
    Location
    Bradford, Vermont, MerryCanna.
    Posts
    18,751

    RE: How can I flatten cupped boards?

    Oops... :)

    You've already gotten good advice. I just wanted to pop by & say "Hola". :)

    -- Tim --



    May your mind's eye
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