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Thread: Drying sweetgum in the fridge- results

  1. #1
    Join Date
    May 2007
    Location
    Florida
    Posts
    624

    Drying sweetgum in the fridge- results

    A while back I posted a question about drying wood in the fridge. Here's the link I was referring to: http://www.sawmillcreek.org/showthre...light=sweetgum

    Well, I finally reached a point where I can say that the experiment is done. I dried the wood in the fridge until the wood was only loosing a few thousandths of a kg per week. I then removed it and let it acclimate to my garage. I started this experiment with green lumber that was just soaking wet the board was approximatley 2' by 6" and a little over 1" thick. On April 13, 2011, I put it in the fridge after weighing it at 1.691 kg. I recorded the weight of the board until the weight actually increased slightly, but basically leveled off at 1.065 kg on July 10, 2011. It was taken out of the fridge on May 9 and weighed 1.076 kg.

    If my math is correct, it appears to have lost 37% of its weight over the course of the experiment. 36.4% was lost in less than a month! Now during this time, the board was just lying on its edge in the back of the fridge with nothing supporting it. As a result, it did warp significantly, but not suprisingly. It was probably 1/4" off of flat from corner to corner diagonally.

    After only about 3 months, I decided to see if there was any detremental effects in the lumber. I ripped the board down the middle to minimize the loss and then face jointed the boards and planed them down to 3/4". There was no noticible amount of movement, whatsoever. The boards are still within a 1/128th of an inch of dead flat, and that movement was likely there after face jointing so much from one side over the other.

    I still do not have a moisture meter. I do live in humid Florida. I am certain that this board is as dry as it will get, within a half of a percent or so.

    Just for comparison purposes, I took another small board out of the attic and weighed it over the course of a couple of weeks in May. The weight never fluctuated more than a few thousandths. I jointed it and planed it flat at 7/8". It was stickered and weighted down. There was very minimal wood movement seen here.

    As far as defects, there were none associated with the drying process. There were 0 checks in the face, edge, or end grain of either board. The boards in the attic are positioned in front of the gable vent fan, which runs most of the day all summer long.

    I will attach a photo of the board with the wieghts and dates written in pencil. You may have to enlarge the photo to read them well, if you are interested in the progression. I also photographed the warpage.

    I would not hestitate to use a refridgerator or attic again to dry short boards in a hurry. I would make sure to sticker them properly though.

    Hope this helps someone...
    Thanks, Dan

    Drying sweetgum 001 (Large).jpg Drying sweetgum 004 (Large).jpg

    P.S. I don't think the one is clear enough after resizing to see the data. If anyone is interested, I will post it in text.

  2. #2
    Join Date
    May 2004
    Location
    Tyler, Texas
    Posts
    2,041
    The wood dried, not a result of the temperature inside the fridge, but because of a low humidity. Heating the wood would actually dry it faster than cooling it if the RH were the same for both methods. That's why kilns are heated. The three factors that affect drying rate are relative humidity, heat and air flow.
    Cody


    Logmaster LM-1 sawmill, 30 hp Kioti tractor w/ FEL, Stihl 290 chainsaw, 300 bf cap. Solar Kiln

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