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AIR DRYING SLABS AND CONFUSED

Discussion in 'Milling & Saw Mills' started by BJD85, Sep 24, 2019.

  1. rarefish383

    rarefish383 Addicted to ArboristSite

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    No advice, I like wormy Pine!
    [​IMG]
     
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  2. BJD85

    BJD85 ArboristSite Operative

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    I did have that thought!
     
  3. buttercup

    buttercup Gone fishing

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    Vacuum bag a stack of boards at a time at 25"HG or higher over night and I assure you absolutely nothing inside that wood is still alive afterwards.
     
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  4. andy at clover

    andy at clover Woods!

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    Interesting... Any chance you have some pics or a tute of how that comes together ?
    Is there a home brew method?
     
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  5. buttercup

    buttercup Gone fishing

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    I'll be back in a few minutes, I'll see if I can find some pictures and I will explain. In the mean time have a look at this site; https://www.joewoodworker.com/
     
  6. buttercup

    buttercup Gone fishing

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    Ok, an introduction and understanding of the forces involved;
    Absolute vacuum (like in outer space) is unobtainable at the surface of the earth, simply because of its nature and immense force, what we are talking about in vacuum processing is in the range of 80% to 98% vacuum (23.6"hg to 28,9inHg).
    To understand what vacuum really is, I'd say (contrary to human explanation) it is "0" pressure - because that is what is out in space. On Earth surface however it represents the weight of the entire earths atmosphere, you might think that the earths atmosphere has no weight at all but it does indeed.
    At 80% vacuum (23.6"Hg / -0,8Bar) the pressure of its content is 8 metric tons per square meter, if you have a stack of boards that is 1 meter wide and 4 meters long - you have a perpendicular pressure equal to the weight of about 8 small cars on to your stack each meter of the length... that's the weight of 32 cars on to your 1x4 meter stack. Pretty mind blowing.

    Now, how to do it;
    Basically you use plastic foil (moisture barrier used in buildings) as a bag material, it typically comes on rolls about 1 meter wide and is folded so the plastic foil is actually 2 meter wide. You fold it over your stack and use sealant (like silicone or similar) to seal it along the edges, the sealant should be as cheap as possible and as thick (viscous) as possible - you don't wait for it to dry - it is used as it is.

    These pictures are from composite processing so you have to imagine scaling it up, but the technique is the same;

    RIMG0006.JPG RIMG0007.JPG RIMG0008.JPG

    The white stuff inside the bag is called "a breather", it is to insure airflow inside the bag. When threatening a wood stack you could use a piece of rope from the tube outlet and in to contact with the wood end grain at some place.
    Just a canal so that the plastic foil don't seal itself between the wood and the tube outlet.

    What it does to bugs;
    Well, aside from that all oxygen is removed - any living organisms that includes any amount of moisture will start to boil.
    Imagine a fish that is pulled from the pressure at 10 000 meters deep in the ocean and up to the surface in a few minutes.

    Since I was doing composite processing (I'm highly allergic to laminating epoxy) making vacuum systems have been a hobby to me, this is the one I'm doing now;
    It includes features and programmable functions (fully adjustable digital vac.switch, different modes, time schedule and other automation) that you can not buy ready made on this planet yet.
    This is a two stage diaphragm pump that (after some love and care) is capable of 98% vacuum.

    RIMG0118.JPG

    You can buy professional vacuum pumps that is capable of continuous running, no need for a vac.system or anything just plug in the tube, start the pump and let it run for a week if you like - but they are expensive.
    Expensive as in you would need to choose between a brand new MS201T, or buying the vac.pump.

    A71691.jpg

    The most cost effective pumps on the market are oil lubricated rotary vane pumps; these are relatively cheap to buy and highly effective, pulls nearly a full vacuum and have good capacity as well.
    These are not suited for continuous running and should be equipped with a vac.switch that turns if off when the required vacuum have been achieved, and turns it on again if the vacuum falls below a certain level - similar to a garage compressor.

    msc90062.jpg
     
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