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Thread: Warped glue up question

  1. #1
    Join Date
    Feb 2007
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    Westphalia, Michigan
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    955

    Warped glue up question

    I did my first glue up of 1" wide x 1/1/4" deep cherry boards for a butcher block style counter top for my brothers house. These were glued up in 3 sections to allow for running them through a lunch box planer to simplify flattening them. So we got the 3 sections done and I set them aside for a while. After returning to the job after a few weeks 2 of the sections have warped pretty bad across in a diagonal direction. They are both warped about 3/8". What did we do wrong? I have been wondering about putting them under gradually increasing clamp pressure to see if I might straighten them. Otherwise it's back to the beginning. The cherry was real dry. I couldn't get a moisture meter reading on them so the boards were less than 6%.
    I'm a certifiable tree hugger. (it's a poor mans way of determining DBH before cutting the tree down)

  2. #2
    Join Date
    Feb 2012
    Location
    central florida
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    208
    Hi;
    are you saying they twisted? are there 3 total sections and only 2 of them warped? I'm asking those questions for other peoples clarification. I couldn't imagine why that would happen if they are twisted which is what i think you mean by warped across the diagonal. that happens when wood is drying but unless your meter is bad your wood is dry. Cupping, that i can understand happening if all the growth rings were laid down in the same direction.

    I can't wait to hear why it happened.

  3. #3
    Join Date
    May 2007
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    Thomasville, GA
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    Paul, can you post a photo of what you have?
    Bill Arnold
    Citizen of Texas residing in Georgia.
    NRA Life Member and Member of Mensa
    My Weather Underground station

  4. #4
    Join Date
    May 2011
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    Cape Cod, Ma.
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    Were they stickered in such a way as to allow uniform air flow? Also, was there a time of day where they were in direct sunlight?
    For future reference never ever leave a glue up partially finished for a few weeks. Wood WILL move. Once you start the process make sure you have enough time to bring it to completion. Even though your wood was dry you introduced a fair amount of moisture into it with the glue.

    Usually when I am gluing up a top for a counter or a table what I will do is plane and joint the wood over a period of a couple of days. By that I mean I will flatten one side then plane the other side flat and joint one edge leaving the pieces over thickness and over sized. Then I will stack the pieces with stickers between each layer and leave them over night. Not in any direct sunlight ever. Then start the process over the next day. Taking off just enough to flatten and joint then plane. If I am not going to be able to glue up the top that day I will again leave it over thicknessed and only bring it to final size when I am ready to glue the entire top. Then at glue up I will ensure proper clamping pressure on both faces and that each piece aligns with the next. (within a 64th). I have a 38" drum sander in my shop so I can sand flat tops up to that width. If they are wider I will make the top in two halves and then sand each of them flat before gluing them together then I only have one seam to clean up.
    Before I got the sander I used to do my clean ups and flatten the top with a mix of scrapers and sanders using straight edges to ensure I didnt cause any dips etc. In your case if you only have the 12 or 13 inch planer you can do the same as you did if you are going to run them through there but do your final glue up immediately dont leave it sit.

    Hope this helps
    He who laughs last, thinks slowest

  5. #5
    Join Date
    Oct 2006
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    ABQ NM
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    My guess is that the planing you did released internal stresses in the wood, causing it to move. I've seen it happen more than once when ripping stock, and given the right (er...wrong) circumstances, I'd imagine the same thing can happen from planing.
    When the going gets weird, the weird turn pro. - Hunter S. Thompson
    When the weird get going, they start their own forum. - Vaughn McMillan

    workingwoods.com

  6. #6
    Join Date
    Feb 2007
    Location
    Westphalia, Michigan
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    955
    I am certain the wood was very dry, maybe too dry. It did occur to me that the glue introduced moisture may have contributed to the issue. What puzzles me is the way the sections warped. I would think they might "taco" (cup) but I didn't expect the sections to warp across in a diagonal direction. The sections never saw any sunlight or drafts. My shop stays a nice 55-60 degrees in the winter. I had considered using cauls but was too lazy to make them. Guess I need to get some suitable caul wood. It never crossed my mind to give the wood time to adjust after machining. We jointed and ripped them to size plus some for planing and finishing and got the sections all done in one afternoon.

    I am used to working with metal and studied metallurgy, machining, welding, etc. I am sure having fun learning about the HUGE variation in the world of wood and it's properties. Wood makes metal look simple.
    I'm a certifiable tree hugger. (it's a poor mans way of determining DBH before cutting the tree down)

  7. #7
    Join Date
    Feb 2007
    Location
    Westphalia, Michigan
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    A further thought occurred to me. I got this wood (cherry) as part of a deal where I bought out a guy's shop. I had just wanted a few of his tools but he insisted I take everything after I made him an offer for the tools. I wonder if the cherry boards were from branch wood? I seem to remember him saying that he had the wood sawed from some trees on his property. These boards were in a pile of shorts he had stashed in the rafters of his basement. I do have lots of cherry lumber over at a friends home, but it is just air dried and has been outside, stickered up in a bunk. We are going to build a kiln this summer to get lumber properly dried.
    I'm a certifiable tree hugger. (it's a poor mans way of determining DBH before cutting the tree down)

  8. #8
    Join Date
    May 2011
    Location
    Cape Cod, Ma.
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    1,553
    its possible. Internal stress in wood is a funny beast. I have had some beautiful African Sapele that was nice and flat in the rough and when rough ripping on the table saw watch it twist into cork screws and wander all over the place sometimes dangerously twisting onto the blade. We used to joke that it was the lone tree that you always see in the middle of the savannah and was wind tortured.
    He who laughs last, thinks slowest

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