Announcement

Collapse
No announcement yet.

How dry should my wood be?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • How dry should my wood be?

    Just wondering EMC for wood on the west coast, and at what percent is good to start working with it?
  • Thread Continues Below...

  • #2

    Re: How dry should my wood be?

    Antoni... Google is your friend. "This is carpentry" has a very good article that discusses wood moisture, how EMC varies with relative humidity of its environment, and how varying RH will affect wood dimensions, whether flat cut or quarter sawn. As my hobby workshop has an RH range of 15%-80% over the year I monitor my shop conditions continually and make panels, cross-grain joints. etc. accordingly. Roy
    Antoni likes this.
    Are you solving the problem, or becoming part of it?

    Comment


    • #3

      Re: How dry should my wood be?

      To find if your new wood is the suitable to work in your shop.
      You have two issues;

      1. Is it at EMC?
      2. is it the same moisture content as your shop?

      You don't need any fancy equipment, you don't need any special moisture meters.


      To find if it is at equilibrium moisture content: as soon as it arrives resaw a piece and see what happens; refer to the second sketch.
      If it stays straight like the middle boards, then your wood is at equilibrium.

      If your wood is at EMC and you put it in your shop, if there is any difference in your shop air moisture then it will effect the wood by introducing or removing moisture from the wood and disrupting the EMC adding stress to the outside of the wood and will show up as wood movement when resawn.

      to find out; set a piece on edge in your shop for a day or two.

      Then resaw it.
      Observe what happens, any difference with your shop will show up as in the sketch.


      Click image for larger version

Name:	wood1.jpg
Views:	1
Size:	21.1 KB
ID:	1166094

      Click image for larger version

Name:	wood3.jpg
Views:	1
Size:	56.5 KB
ID:	1166095
      www.solidwoodmachinery.com

      Comment


      • #4

        Re: How dry should my wood be?

        Originally posted by hennebury View Post
        To find if your new wood is the suitable to work in your shop.
        You have two issues;

        1. Is it at EMC?
        2. is it the same moisture content as your shop?

        You don't need any fancy equipment, you don't need any special moisture meters.


        To find if it is at equilibrium moisture content: as soon as it arrives resaw a piece and see what happens; refer to the second sketch.
        If it stays straight like the middle boards, then your wood is at equilibrium.

        If your wood is at EMC and you put it in your shop, if there is any difference in your shop air moisture then it will effect the wood by introducing or removing moisture from the wood and disrupting the EMC adding stress to the outside of the wood and will show up as wood movement when resawn.

        to find out; set a piece on edge in your shop for a day or two.

        Then resaw it.
        Observe what happens, any difference with your shop will show up as in the sketch.


        Click image for larger version

Name:	wood1.jpg
Views:	1
Size:	21.1 KB
ID:	1166094

        Click image for larger version

Name:	wood3.jpg
Views:	1
Size:	56.5 KB
ID:	1166095
        Thank you Mark, thats a handy little trick!

        Comment


        • #5

          Re: How dry should my wood be?

          Does the cutting of the original board have any bearing? Quarter sawn - Flatsawn
          Egon
          from
          The South Shore, Nova Scotia

          Comment


          • #6

            Re: How dry should my wood be?

            Originally posted by Egon View Post
            Does the cutting of the original board have any bearing? Quarter sawn - Flatsawn
            Yes it has bearing on the amount of movement.
            If you take any piece of moderately dry wood and;
            1. add moisture to it it will expand.
            2. remove moisture from it it will shrink.

            If you add moisture to only one face of a piece of the wood the cells will expand on that face at that time
            If you remove moisture from one face the cells will shrink on that face at that time.

            If you put dry wood in a damp room the wood will eventually soak in enough moisture to equalize with the air in the room.
            If you put wet wood in a dry room the wood will release water until it balances with the atmosphere of that room.

            If you hang a piece of dry wood up in the air in a damp room, so that the air can reach all of the wood, the wood will draw in the moisture and all of the exposed fibers will start to swell, so you will have a tension all around the wood, until the moisture makes its way through to the center and then all of the fibers will be equally wet and you will have attained wood nirvana or EMC. This is why i suggest resawing a piece that has been in your shop for a few days to see if your shop has affected the outside fibers by changing the moisture content.

            Whatever your wood and shop moisture content are in, if you sticker you wood and leave it in your shop it will eventually acclimatize and settle down.
            All of the stress is caused by a change in moisture.
            Resawing the piece will let you know if there is stress being introduced by being in your shop and in what way, adding or removing moisture from your wood.

            The way in which your wood is cut makes no difference in this determination it only makes a difference in the amount of movement.
            A board with a face of quarer sawn fibers will still swell when you add moisture and still shrink when you remove it, just not as much as flat cut face fibers.

            Antoni likes this.
            www.solidwoodmachinery.com

            Comment

            • Thread Continues Below...

            • #7

              Re: How dry should my wood be?

              Mark if there is stress in the board could it not bend or twist independent of the moisture issue? I am thinking here of thicker boards that are resawn. Maybe 4 inches into two of 2 inches thick.

              Comment


              • #8

                Re: How dry should my wood be?

                I found this very helpful - it's all you need to do/know.

                Wood By Write - How to tell when your wood is dry enough to use
                https://youtu.be/O1F5PcLDCjg
                Antoni likes this.

                Comment


                • #9

                  Re: How dry should my wood be?

                  Originally posted by dwoody View Post
                  Mark if there is stress in the board could it not bend or twist independent of the moisture issue? I am thinking here of thicker boards that are resawn. Maybe 4 inches into two of 2 inches thick.
                  Hi Dennis, We are talking kiln dried lumber ; If your lumber arrives and you cut it immediately you will know if it has been properly dried. If it warps as you cut it then it has been improperly dried, (Casehardend) it has been dried probably too fast and has trapped stress inside. That's why i suggest that you check it when it arrives, that removes your shop from the cause. Drying Wood, especially thick wood creates a lot of stress as the moisture moves from the outside first and the outside starts to shrink, while the inside is still wet and swollen. If it is not dried correctly the stresses are not relived when the drying is finished.
                  www.solidwoodmachinery.com

                  Comment

                  Working...
                  X