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Thread: checking, can I stop it

  1. #1

    checking, can I stop it

    Hi - I bought some huge, rough sawn, walnut boards with live edges. The boards aren't green but I have no idea about when the boards were cut, if the boards were kiln dried, etc. I found checking on some of the ends. The boards are inside my shop but I want to do anything I can to stop the checking. Maybe its too late but would appreciate any tips. Thanks.

    Eric

  2. #2
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
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    7,084
    Quote Originally Posted by Eric Rathhaus View Post
    Hi - I bought some huge, rough sawn, walnut boards with live edges. The boards aren't green but I have no idea about when the boards were cut, if the boards were kiln dried, etc. I found checking on some of the ends. The boards are inside my shop but I want to do anything I can to stop the checking. Maybe its too late but would appreciate any tips. Thanks.
    Eric
    It's too late for the checks that are already there but not to late to prevent further checks.

    Do you have a moisture meter? If the boards are dry, the wood is stable and the ends won't check any more. Green wood will check as it dries since the moisture leaves the end grain very quickly - the wood will dry and shrink near the ends while still very wet just a little ways back. The gap left by a check lets moisture escape even quicker so the the check deepens. The tendency to check decreases as the board gets drier overall. Some species can start to check almost immediately after sawing, especially when it's hot and dry or in direct sun or from the moving air if transported in a truck or trailer.

    If the wood is green, sealing the end grain with a wax sealer such as AnchorSeal will slow the drying and minimize checking.
    If the wood is partially dry the the sealer may help some.
    If the wood is almost dry the sealer won't make any difference but the wood is done checking by then.
    (By "dry" I mean at equlibrium moisture content, EMC, which depends on the enviornment - around 13-15% outdoors in many parts of the country, perhaps 8-9% in indoor conditioned spaces)

    I cut a lot of wood into woodturning blanks, mostly blocks and turning squares. If the wood is freshly cut dripping wet I square up the ends and coat with AnchorSeal.
    If I get wood that is still mostly wet but has been sitting long enough to start checking, I always cut away the checks before sealing. (Cut a thin slice and bend it a little - if it easily breaks at a radial line checks are there even if you can't see them.)

    If you check your boards with a moisture meter and they are not completely dry you might consider first trimming away the checks then sealing. Sealer applied over the checks will help some, but not as well as if the checks are cut away first. (In my experience.)
    If you check the moisture and the wood is dry there is no need to seal. You can cut away the checks now or cut them away later.

    BTW, with unknown boards and no moisture meter I'd probably trim the checks and seal the ends. If you have a few months, weigh one board and check it again periodically - if dry the weight will stay constant. If you don't have a meter and really want to know the moisture and can cut a small sample out of the center of one, the Oven Dry method will give you the exact moisture content: https://sawmillcreek.org/showthread....ven-dry-method

    You can often see how deep the cracks extend by looking at the sides of the boards, easier if you plane a bit smooth. Checking usually doesn't extend more than 6 inches in a log.

    AnchorSeal (sometimes labeled as Green Wood Sealer) is available by the gallon at WoodCraft and elsewhere. AnchorSeal is painted on with a brush and is white until it dries, then it is clear wax. You can see some not yet completely dry in this picture of some woodturning blanks of ambrosia maple:

    ambrosia_maple_IMG_20171202_175922_594.jpg

    JKJ

  3. #3
    Join Date
    Mar 2015
    Location
    cleveland,tn.
    Posts
    290
    if you have extra bar clamps put those on the board near the end not to tight as that might cause cupping or clamp in the middle of the bar clamp and tighten up a little more. as the board dries you will need to reset tension of clamps, if checks are deep into the grain you could try gluing it up when you clamp and see if the ends can be salvaged at full length.

  4. #4
    Thanks to both of you! I don't have a moisture meter but will borrow one from a friend.

  5. #5
    Join Date
    Feb 2003
    Location
    Griswold Connecticut
    Posts
    6,086
    I hammered big electrical staples across the checks, into the rough sawn walnut boards I have. I'll let you know if it worked this spring, but so far it "appears" to have helped. The boards were also sealed with anchor seal.
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

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