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  1. #1
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    Oven drying small pieces of wood

    Is it feasable to dry small pieces in a home oven? If so, what's the process? What temp for how long?

  2. #2
    Sonny Edmonds
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    RE: Oven drying small pieces of wood

    I don't think you want to do that, and I'll tell you why.
    I had some pieces of dry Oak I wanted to turn on my lathe. I had cut them into blank sized pieces and left them for about 8 months in a pile in the shop.
    Well, one day I figured I was ready to try turning one, and did.
    I encountered a solder termite and a bunch of babies along the way.
    Well, termites are the LAST thing you want around a wood shop, so I dispatched them with tools and mineral spirits. (I thought.....)
    Later on, the piece was setting soaking up BLO and that started driving more little wrigglers out of the holey wood.
    So I tried nukeing them in the microwave. They acutally liked it! Got more and more excited and wriggely.
    Hummmmm......
    So Betty sez she has one of them oven bags for meat and offers it up for me to try baking the tarnation out of the little white wrigglers crawling out of the wood at an accellerating pace.
    (Hang On, I'm gettin there......)
    I tried baking the durn fool near finished bowl in the oven at 350 in the closed up bag. After about 20 minutes, our eyes started burning something fearce!
    I went and got the bag out of the oven, which darn near knocked me down when I opened the door.
    When I opened the oven bag in the shop, everybody beat feet for the outside before we died of the fumes! Winderz and doors where opened, the DC on the shop was turned on and a hose put into the kitchen, and it was damned cold outside, too. Even the dogs were looking at me and the open doors and didn't want to step foot back into the house.
    Well, the rest of it is that I baked the other blanks of that termite tortured Oak to kill any more of them darn termites. But about 1/2 of an hour or so was all I could stand, and it had to be on a warm day with the house opened up and nobody home.
    Wood gasses off when it is heated. And trying to hurry it up by using the oven I wouldn't recommend.
    But if you want to try it, use a very low heat, and make sure you and nobody else is asleep during the experiment.
    It will take days, most likely. Weeks even.

    PS: I was using an electric oven.
    And never ever put BLO soaked wood in there. Them fumes are something awful! Kinda like consentrated smog. Wooo-weee! :P

    LMAO about it now. :7

    :D

    [link:www.sonnyedmonds.com | Sonny Edmonds] http://home.earthlink.net/~sonnypie/vortex_smiley.gif
    "Precision Firewood Specialist"
    God Bless America !
    One Nation Under God!


  3. #3
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    RE: Oven drying small pieces of wood

    ... and you laughed at me for stirring paint with a drill press!!

    [font size ="7" color ="red"]B [/font][font size ="7" color ="blue"]a [/font][font size ="7" color ="green"]h [/font][font size ="7" color ="cyan"]a [/font][font size ="7" color ="red"]h [/font][font size ="7" color ="yellow"]a [/font][font size ="7" color ="cyan"]h [/font][font size ="7" color ="green"]a [/font][font size ="6" color ="red"]h [/font][font size ="6" color ="blue"]a [/font][font size ="5" color ="green"]h [/font][font size ="5" color ="cyan"]a [/font][font size ="5" color ="red"]h [/font][font size ="4" color ="yellow"]a [/font][font size ="4" color ="cyan"]a [/font] [font size ="7" color ="green"]! [/font][font size ="7" color ="green"]! [/font]

  4. #4
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    RE: Oven drying small pieces of wood

    I have dried tons and tons of oak in the oven (uhh, a little at a time :) )... the pieces were steambent, and drying them in the oven worked great for "freezing" the shape without waiting days for them to dry. Use the lowest setting, and make sure to place them as far away from the heating "coils" as you can.

    30 minutes at 150 will do a lot....

  5. #5
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    RE: Oven drying small pieces of wood

    Marc,
    I remember one of the correspondents to the board offering a long and detailed explanation of oven drying wood including weighing it as a basis for determining moisture content. I am sure it was before the great crash. Do you recall it and is it possible to recover that tutorial?

    Chris Moore
    West Palm Beach, FL

  6. #6
    Sonny Edmonds
    Guest

    RE: Oven drying small pieces of wood

    Well of course I did!
    Just like when Kitty concked you with a gallon of paint.
    Or Panic zapped his pee-pee on his Unisaw with static.

    But them fumes from those chunks of oak were knarly! Especially the one with BLO on it. WOW!

    I still LMAO when I recall that cold winter night, and the dogs looking at me like, "What the hell did you do that for?" And blowing their noses to clear the fumes.
    I find it rather humorious when the pups get discusted. LOL! :7

    :D

    [link:www.sonnyedmonds.com | Sonny Edmonds] http://home.earthlink.net/~sonnypie/vortex_smiley.gif
    "Precision Firewood Specialist"
    God Bless America !
    One Nation Under God!


  7. #7
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    RE: Oven drying small pieces of wood

    now that's a story to remember from Sonny :)

  8. #8
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    RE: Oven drying small pieces of wood


    I have been thinking of building a kiln to dry wood. Something about 6 to 8 foot long, about 4 foot high and maybe 2 feet deep. I was thinking that, being I have build rod ovens, for keeping welding rod dry and free of moisture, (they were warm enough to cook a TV dinner in about 3 hours) that I could make a kiln that could dry wood too. What I thought was if I could bring the box to about 120 degrees this would get the job done, maybe not real fast but it would work I am sure 150 would work a lot faster. If the wood touched the element or source of heat you would end up with a smoker, and that is not a bad thing if you have enough fish to fill it *L* I have not moved forward on this, yet. I live in the Mid Atlantic so we have lots of Oak and Maple that I can get green at low prices.


    Cut it, Shape it, Sand it to fit, Then two weeks later the humidity changes the size and shape if it. This wood stuff makes me insane.

  9. #9
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    RE: Oven drying small pieces of wood

    I didn't find anything in our archives... may have been deleted... so I searched the web and found this... it hurt my widdle bwain but hopefully you will find it useful....[hr]Water and Wood
    An excerpt from Drying Oak Lumber

    by Eugene M. Wengert

    Department of Forestry
    University of Wisconsin
    Madison, WI

    Part 1 (of 3) from Section 3:
    Interaction of Wood and Water

    Main Points
    How water exists in wood
    Moisture content measurement--oven-dry method
    Moisture content measurement--electrical resistance meter
    Shrinkage in the three directions

    Water In Wood
    The living tree uses water as the medium to convey food between the roots and the leaves. The living tree, therefore, contains large amounts of water. For every 1 pound of wet, living wood, about 55 to 60 percent is dry wood (that is, cells) and 40 to 45 percent is water. Some of this water is contained in the cell lumen and some is contained within the cell wall itself. Water in the lumen is called free water while water in the walls is called bound water. These terms arise because the free water is not held chemically within the cell, while the bound water is held by hydrogen bonding. Free water evaporates as easily as water from a tea kettle; however, bound water requires a little extra energy for evaporation. Further, and most importantly, when the bound water leaves the cell walls, the cells shrink. When all the free water and all the bound water has been removed from a cell (at temperatures no greater than 217o F), the cell is at 0% MC; this is also called bone-dry or oven-dry.

    Measuring Moisture Content--Oven-Drying Method
    In order to avoid confusion when discussing MC and to prevent any variations in measured MC values attributed to the measuring techniques used, standard methods of measuring the MC of wood have been established. These methods are described in detail by the American Society for Testing and Materials (ASTM), Standard D-4442. The important features of the Standard that apply to lumber drying are summarized here.

    Units
    In lumber drying, the MC of wood is expressed as a ratio of the amount of water in a piece wood compared to the oven-dry weight of wood. This is called the "moisture content on the oven-dry basis." In lumber drying, MC is always expressed in percent. Specifically,

    (Amount of water in the wood)
    % MC = ------------------------------- x 100
    (Oven-dry weight of wood)

    (Wet weight - Oven-dry weight)
    = -------------------------------- x 100
    (Oven-dry weight of wood)

    The wet weight in the above formula is the weight of the piece at the unknown MC. It could be the weight when green, partly-dried, air-dried, kiln-dried, or in use. The wet weight is also called the green weight, the current weight, or the present weight.

    The measuring units used for weighing--pounds, grams, kilograms, or ounces--are not critical, so long as all weights are in the same units. Do not mix measuring units. However, because the decimal system of grams or kilograms lends itself to calculations, these units are commonly used.

    When an electronic calculator will be used, the following version of the formula is suggested, as it will save a little time when entering numbers and may reduce entry errors.

    (Wet weight)
    % MC = {[-------------------] - 1 } x 100
    (Oven-dry weight)

    The calculation procedure when using an electronic calculator is summarized in Table 7.

    Moisture Content Determination
    The oven-drying method of MC determination is the fundamental MC measuring method when drying oak lumber. All decisions on how to dry oak successfully depend on the knowledge of the correct MC of the lumber. Therefore, it is essential to be intimately familiar with this procedure. Variations cannot be permitted if quality is the #1 concern in drying.

    First, a sample of wood is prepared. For small pieces, the entire piece may be used as the sample; for lumber and large pieces of wood, a smaller piece, called a moisture section, full thickness and full width but only an inch along the grain (or along the length of the lumber) would be used. The moisture section chosen for oven-drying usually is free of knots, edge splinters or loose slivers, and bark.

    The moisture section is weighed, immediately after cutting, to the nearest 0.01 grams, if under 100 grams total weight, or 0.01%, if heavier. This wet weight is written on the section with a permanent marker.

    The section is then placed in an oven at 215o to 217o F and left there until it stops losing weight (about 24-hours, but it can be longer; it seldom is shorter). To determine if the section is oven-dry, the section is weighed, put back in the oven for another hour, and then weighed again. If the two weights are the same, then the section is oven-dried. The oven-dried weight is then written on the section with a marker.

    It should be noted that an oven with internal forced circulation (that is, one with an internal fan) is much better than a natural convection oven. When the value of the lumber in a kiln is considered, it does not pay to cut corners by using a noncirculating oven when measuring the critical variable of MC.

    Alternative Method of Oven-Drying: Using a Kitchen Microwave
    An alternate method of oven-drying is available using a kitchen-type microwave oven. The method is fully tested and accurate if and only if the following criteria are met: the microwave has a carousel tray; the sections must be placed on the outer edge of the tray; the sections must not touch each other; and the oven must be run on medium low (360 watts) to low power (200 watts). Medium power (490 watts) can possibly be used when four or more sections are in the oven. If the sections begin to smoke, then the power level is too high. Other techniques and equipment will not be satisfactory.

    Typical microwave oven-drying time is 20 to 30 minutes for green pieces and 10 to 15 minutes for dry pieces. After 20 minutes (or less if the initial MC is lower), the section is weighed, dried for another minute, and reweighed. If the two weights are the same, then the section is oven-dried. The calculation procedures for MC are the same as with the hot air oven.

    Exercises: Moisture Content Calculations
    As MC is the most critical measurement made during drying, several problems are presented (Appendix B) to assure that the reader can properly calculate MC. These exercises should be completed before proceeding further. Note: For kiln drying, MCs are calculated to the closest tenth of a percent, such as 34.7% MC, rounding the answer. (Answers are rounded up when the hundredth is greater than 5; that is, 34.752 would be rounded up to 34.8, while 34.748 would be 34.7.)

    Professor Gene Wengert is Extension Specialist in Wood Processing at the Department of Forestry, University of Wisconsin-Madison[hr]

    [link:www.woodweb.com/knowledge_base/Water_and_Wood.html|Click here] to go to WoodWeb
    There will be a test in the morning :)


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