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Thread: Help deciding between mini-Ligno meters

  1. #1

    Help deciding between mini-Ligno meters

    Iím looking to buy my first moisture meter. It will be used mostly to check when rough lumber has acclimated to my shop environment. I need help deciding between two mini-Ligno models. There are other cheaper models but Iím set on a mini-Ligno at this point.
    For the purpose of confirming shop acclimation, my understanding is that the MC number itself is less important than the trend. My understanding is that one can be fairly certain their lumber has finished acclimating when daily MC readings become nearly constant for some period of time. So if I bring home some lumber that was sitting outdoors for months and let it acclimate in a climate controlled shop, I should expect to see the MC reading to trend up or down (but probably down) over the course of several days or weeks, until it stabilizes and reads the same or nearly the same for some number of days. Itís somewhat subjective, but the point I took from multiple sources recommending this approach is that Iím looking for the curve to flatten out.
    Assuming anything I just said is true, Iím thinking I donít necessarily need to spend 2x the money for the DX/C. It does have over 40 wood group settings whereas the E/D only has 2 groups (hardwood and softwood), but do I need 40 groups for my purpose of checking acclimation? Seems like the E/D would get the job done and let me track the trend of MC readings.
    Just curious if any other mini-Ligno owners out there can share some insight.
    Thanks!

  2. #2
    You are on the right track. Two important points: 1) monitor and if possible control your workshop humidity and keep it close to the conditions in which your work will end up, and 2) be aware that there is typically a moisture gradient from core to shell in your lumber which may be hard to assess with short pins and hard species. It can be difficult to penetrate hard maple for instance to any depth without long pins and a slide hammer, so to get an accurate read on lumber over 1" thick you may have to make a fresh crosscut to pin the endgrain.

    You can get an equally accurate non-destructive reading of acclimation with a scale- when the sample board stops losing weight it is in equilibrium with its environment.

    I use a moisture meter mainly to gauge the mc of lumber I am buying or drying, and occasionally to assess acclimation in the shop. I generally get material in well before use so I know where it's at without too much checking.

  3. #3
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    Keven's advice is spot on from my experience. I use a mini Ligno, the really cheap one, for checking lumber when I'm buying and that's about it. When I bring wood into my shop I cut a piece and record it's weigth, then weigh it every day or so. When it stops changing weight it's at equilibrium. My shop has pretty good control of RH and temp. so this works well for me. If the RH in your shop isn't controlled and moves around much, however, you're shooting at a moving target.

    John

  4. #4
    I bought a mini-ligno from Grizzly, on sale. Was not aware of more than one model. Seems fairly accurate for a cheap meter. The Wood doctor says you need to spend about 400 to get one really accurate, if i am correct. Don't know how you can get your wood dry without a kiln, although I have kept a supply of air dried wood in my shop for years, getting it acclimated. Building a solar kiln will make it so you can build all you want without waiting for wood to get ready. My thinking is I need to build about 4 chests at a time to catch up with all the chests everyone wants, just in my family.

  5. #5
    Thanks for the replies and suggestions to use weight instead of MC. How accurate does the scale need to be? I have a small postal scale that can measure to 0.1 oz.

    Wouldn't the small cut-off piece dry a lot faster than the whole board it came from? I'm wondering if the cut-off could reach equilibrium while the whole board has not.

  6. #6
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    If you make your sample board at least 2 feet long it will dry at the same rate as the rest of your lumber. I use a 4000 gram scale, accurate to 1 g. My sample boards often weigh around 3000 grams, so the inaccuracy is 0.03%. If your scale is 0.1 oz and your sample weighs 3000 gms (appro. 100 oz), then the inaccuracy is 0.1%, still good enough. Put your sample board in the middle of the stack on one side, half way up, not on top.

    John

  7. #7
    Quote Originally Posted by John TenEyck View Post
    If you make your sample board at least 2 feet long it will dry at the same rate as the rest of your lumber. I use a 4000 gram scale, accurate to 1 g. My sample boards often weigh around 3000 grams, so the inaccuracy is 0.03%. If your scale is 0.1 oz and your sample weighs 3000 gms (appro. 100 oz), then the inaccuracy is 0.1%, still good enough. Put your sample board in the middle of the stack on one side, half way up, not on top.

    John
    Thanks John, that all makes sense. I think my scale actually does have a grams mode that is probably accurate to at least one or two decimal places.

    I think I'm okay with a sample piece as large as 2' if I can get some usable pieces out of it for whatever project I'm working on.

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