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Moisture Meters

Post in 'The Gear' started by ArsenalDon, Feb 17, 2013.

  1. TreePapa

    TreePapa Minister of Fire

    Joined:
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    583
    Loc:
    Southern Calif.
    Well, the moisture meter is a help to me. I get a wide variety of firewood (i.e. "yard wood") much of which I can't identify. Some very different density of wood, so "it feels heavy" or "it's light it must be dry" are as reliable as I once thought. I do not usually have two or three years' wood stockpiled (except for the quarter cord + of pitch pine, good only for splitting in to small fatwood fire starters. That is about a 30 year supply, if I am consistent in splitting up little fat wood bundles and giving them as gifts. Anyone for some ugly fatwood?) As a fireplace burner, I try to use the driest wood I can, cut small and burned right to have the least smokey fire I can. The meter does help with that. I've had some wood I thought "must be close" only to have the meter go beyond it's top range (about 30%). Others are down to 10% and burn great.

    And I have one small stack of some yard wood or other with 1/4" thorns, really light, not split (mostly < 2"), seems very dry, and STILL has moisture content of about 25%. That stuff may well go in the green (yard waste) can, as I'm sure it has just over zero BTUs. I'm fairly certain if I split it, it will season in one summer and be very dry the next, but that's prolly too much effort for too little return since it will still have little fuel value and those thorns make splitting a pile of fun.

    Peace,
    - Sequoia
    OldLumberKid likes this.

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  2. StihlHead

    StihlHead Guest

    +1

    I read his post the same way that you did.

    Not everyone has the luxury, means, or luck to have years of wood stacked in advance. I sure don't. A MM does in fact give you information that is valuable. Different species of wood dry at variable rates. Wood dries differently when stacked differently and/or is stored in different locations and in different climates. Also some so-called seasoned wood from unknown sources (like CL) will have an unknown moisture content, and the value of having a MM can be greatly beneficial in finding out what you have to deal with or what someone is trying to sell you. Also similar trees can be highly variable in moisture content, for example trees cut this time of year can be rather dry compared to when they are cut later in the year.

    So in the end, I do not see what the major fuss is over buying a tool that costs all of $11 and can give you a heck of a lot of good information. I also do not understand the arrogant statement that we are all supposed to have at least 3 years of firewood stashed ahead of time like Scotty the Overlkiller, and thus have dry wood available that does not need measuring with a MM. I mean, really.
  3. MasterMech

    MasterMech Guest

    Because to some very high end cabinet builders, the precise amount of moisture in the wood matters. Honestly, burning 25-30% MC firewood isn't any more dangerous than burning 15% MC fuel. The danger is in neglecting the chimney maintenance.

    You're not going to burn your house down 'cause you tossed a "hisser" in the stove.

    I have a $30 MM I picked up at Lowes. It's occasionally useful for proving to the young and old alike that dead trees aren't nearly as dry as they think they are.
    OldLumberKid and StihlHead like this.
  4. StihlHead

    StihlHead Guest

    As for why some meters are more expensive than others, the el cheapo models are pin types and based on the electrical qualities of Doug Fir (at 70 degrees I believe it is). They cannot be calibrated for different species, or for different temperatures. They are also not as precise, and have a greater margin of error. So they are good for an estimate, but not a highly accurate reading. For firewood, a few percentage difference in wood moisture variation is not a big deal. You can also use a calibration chart to adjust for different wood species.

    More expensive moisture meters are more precise and of variable pin type that can be calibrated for several wood species groups, usually A, B and C, each a class of different wood types. More expensive still are meters that can be calibrated for more wood species types, or meters that use electromagnetic fields to scan the wood moisture content without having to press pins into the wood. These allow for measuring more types of wood and/or rapid assessment of wood moisture. Really high end wood moisture meters account for air temp dew point, vapor pressure and humidity, they can be calibrated for many different specific wood species, they have both pinless and pin scan capability and may have an external probe, and they are built for rugged conditions and use. Beyond that you can get them with Bluetooth to upload data to computers or remote equipment, and to controllers of wood drying equipment.

    For cabinet makers like my nephew, wood moisture can make a huge difference. Similar with wood workers who commonly use wood moisture meters to make sure the wood is dry before carving. They are also commonly used to make sure wood flooring is at the right percentage before installing. They are also used in wood mills/yards that kiln dry lumber, and in wood manufacturing facilities that make things like engineered lumber, glue-lams, and baseball bats.
    OldLumberKid and Don Williams like this.
  5. Lumber-Jack

    Lumber-Jack Minister of Fire

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    I'll start out by saying I've never had, or tried to keep, 2 or 3 years worth of wood on hand, and yet, all the firewood I burn is <20% MC.
    How do I do it?
    Easy, I cut down and process enough standing dead trees in the summer or fall that I plan to burn that winter.
    How do I know the dead trees I process for firewood are <20% MC?
    I use a moisture meter. Pretty simple really, much simpler that storing mountains of wood in my yard and waiting for it to dry. So you see, the old adage about how you have to get 2-3 years ahead doesn't apply to everyone.

    To address Don's question, there are a basically a couple main types of hand held moisture meters out there, standard pin type, and pinless. You can read about them here.
    The most common type used for measuring firewood MC is the pin type, which is generally less expensive than the pinless type, but even in the pin types there is a wide cost difference between models, ranging from $10 to $300. Frankly I don't think the $300 models are any more accurate than the $10 ones, but the $300 ones probably look cooler and are built better. Whether they cost $10 or $300 the pin type work exactly the same way, the reading of %MC is determined by measuring the electrical resistance between the tips of the 2 pins when you stick them in the wood. Since it can take quite a bit of force to push the pin into the wood sometimes, it might be worth considering that the $10 ones may not be able to hold up to the repeated abuse of shoving those pins into hard wood. Of course, at that price you could always buy a spare in case you push a little too hard one time and break it.
    One thing to keep in mind is what range that the meter you are buying is calibrated for. They all have a narrow range of MC where they are the most accurate, no meter will measure from 0% - 100% accurately. Ideally for measuring firewood you'll want one that is most accurate between 10%-25%, since that is the MC range we want to get our wood. Fortunately most MC meters sold fall within that range, so they aren't hard to find.
    OldLumberKid and Don Williams like this.
  6. Jack Fate

    Jack Fate Feeling the Heat

    Joined:
    Jan 17, 2013
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    406
    Loc:
    Northwest Ohio
    Maybe the $550 meter is made in the US & certified as opposed to China

    I paid $56 for a stove top temp gauge (PTC) Us made & certified .

    This stove top meter was recommended here in an older post.
    So far very happy with it also have 3 cheap ones
  7. ArsenalDon

    ArsenalDon Minister of Fire

    Joined:
    Dec 16, 2012
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    750
    Loc:
    Meadow Valley, CA
    And since in our county we are ONLY allowed to cut snags I will end up in a very similar situation as you Randy. My goal is 2 years worth just for convenience in case something were to happen to me so I could not gather at the beginning of a season for some reason, but who knows if that goal will happen.

    Good to know as I look for one.

    So the bottom line is a huge thank you to Randy and Stihlhead. I knew someone (and as it turns out two someones) would have a great explanation as to why the big price swings and as to why most of us could use a MM.

    A lot less painful than throwing out some smart*ss answer and then fighting over it. :rolleyes:
    Lumber-Jack likes this.
  8. Lumber-Jack

    Lumber-Jack Minister of Fire

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    Don, I'm fortunate enough to have figured out a source of trees that are reliably <20% MC, but the way I determined which trees were <20%, and which ones were not, was by using a moisture meter.
    Our firewood permits also ONLY allow us to cut standing dead trees "snags" or fallen trees, but even when cutting those, as I'm sure you are aware, you can still run into wood that is still too wet to burn properly. Lots of people here cut anything dead and will burn it right away. Some of it will be OK and some of it will not, the problem is they don't know the difference, the reason being is they don't have, or use, a moisture meter, nor do they put any thought into it.
    The benefit of having a moisture meter is, if used properly, it allows you to determine which of your wood is ready to burn and which is not, or in my case, it allowed me to select which trees I want to cut in the first place. With the help of my MM I can now visually determine which trees will be <20% MC and avoid ones will contain more moisture. And since I don't have a lot of room at home to store excess wood, this system has been a real benefit to me.
    Of course even if you can't find trees that are totally dry (<20% MC), you could use a meter to select which parts of the snags are good to go (usually the upper branches), and which are not (usually the lower trunk), which could be very important to people who are just starting out burning. Of course I know you realize all this, but obviously, not everyone out there is clever enough to figure that out, thus the need to spell it out. ;)
  9. Valhalla

    Valhalla Minister of Fire

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    Loc:
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    A moisture meter is just a "nice to have tool" if you process your own wood fuel, as most of us seem to do. The only essential that I see for it is if one buys or brokers "seasoned" wood fuel, where the moisture value is an inherent component of the current cost or fuel usability.

    I now keep it with my DVM and electronic stud/wire finder.
  10. firebroad

    firebroad Minister of Fire

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    I had no experience with wood moisture two years ago, I was at the mercy of "seasoned and ready to burn" dealers that knew nothing of the new EPA stoves and their appetites. Though I could probably make an educated guess based on what I learned here, I found a moisture meter a useful diagnostic tool, just like the IR temperature gun I use for my insert.
    Having less than ideal wood, I found that some of the splits were tolerably dry, while others were pretty dam near waterlogged. I used the meter to sort out the now and later wood, and used it recently to diagnose some splits that had been stacked since November of 2011 and are still a little on the green side. I also used it to test some treated lumber that I was planning on painting. At this point I can pretty much tell what's what by the weight and appearance, but sometimes even that can fool me. Do I feel like I wasted my money? Nope. LumberJack and Stihlhead, thanks for the insight into the various quality, I learned something new once again here!
    milleo likes this.
  11. StihlHead

    StihlHead Guest

    I used to leave some standing snags on my ex's and my separate woodland properties (each over 100 acres) in case we ran out of wood for the large appetite OWB. They typically were alders and grand firs, but some were white and black oaks that had been crowned out by taller firs. They made for a ready supply of near dry wood that got us through 2 late cool wet springs. I did not have a meter to test them before burning though. With a pre-EPA OWB you can burn green and/or wet wood, as well as dry. If you run out of dry wood there is really no other option. It wood have been nice to have a meter then to select the dryer wood in the firewood stacks, and select the dryer sags to cut down.
  12. WarmGuy

    WarmGuy Feeling the Heat

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    Far Northern Calif. Coast
    I also have the HF version. It works fine, but I rarely use it.

    It can be handy if you have logs stacked in different locations, or from different scrounges, and you want to figure out which to burn next.
    firebroad likes this.
  13. Kenster

    Kenster Minister of Fire

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    Hey, Nixon! Your rant was your 500th post on this forum. Congrats! (sorry, no prize.)
    MasterMech likes this.
  14. Kenster

    Kenster Minister of Fire

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    You do know that you have to measure the inside face of a freshly split piece, don't you? Sticking the probes into the ends or on the outside of the split doesn't do any good. Forgive me if you already know that. Others may not.
    Valhalla likes this.
  15. Kenster

    Kenster Minister of Fire

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    A bunch of us on this forum have bought the $30 "General" at Lowes. It gives pretty good ball park measurements. I'm finally about four years ahead so I don't worry too much about it. Last year I had so Pin Oak in stacks for about nine months. It sure felt light and dry. I stuck the meter into several fresh splits and came out with 15-18%. That was from a healthy green oak that was storm downed, not standing dead. The reason for this was a brutally hot summer with over 100 days of temps up to 110 degrees and hot, dry wind all summer. This was a rare, fast forward seasoning for oak but having the MM backed up my feelings that the wood was way ahead of schedule.

    I now have four years of wood in the bank but when I was still scrounging, I found the the MM helpful in testing wood picked up along the side of the road.
    Valhalla likes this.
  16. colin.p

    colin.p Burning Hunk

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    Ottawa Canada
    I bought an MM up here in our Canadian Tire store, a Mastercraft model. I have no idea who actually makes it, but only paid $20 for it. I use it occasionally, when I split a piece to check it out. Sometimes, the moisture content is higher than I thought, sometimes lower. However, I bought it because I wanted to belong.:p
    Valhalla likes this.
  17. tim1

    tim1 Member

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    columbia river gorge,portland or
    I am with you guys, I just wanted one. my wood is 3 years seasoned and dry. Goes with all my other tools. Tim
    Valhalla likes this.

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