Decided to Buy a Moisture Meter

[Eric Johnson]

I'm into a bit of wetter wood at the bottom of a stack, apparently, and have noticed a big difference in getting gasification going from a cold start. It's a lot harder. Nofossil has made the point several times that once you get gasification going, you can get by with less-than-optimum wood. In my experience, that's true. So I've learned to always start my fires with the driest wood, and then after I've got a good flame going, to put on the wetter stuff.

Like trying to burn wet or green wood in any stove, furnace or boiler, you can do it, but it's takes more work and thought, and the results aren't as good as burning uniformly dry wood. I can imagine the frustration of somebody who buys a gasifier and tries to make it work with wood that's only partly dry (say, wood cut the previous summer). I've decided to buy a moisture meter. For the $25 or $50 that they cost, I think they should be standard equipment with any new gasifier. Otherwise, wood condition is just a guess, and you can't adequately set the air adjustments on your boiler with green wood.

I see moisture meters on sale from $30 to up over $200. I assume the expensive ones are for kiln driers and woodworkers who need to know mc with some accuracy and precision. I'm guessing that one of the cheaper ones would be fine for firewood. Any recommendations?

 

[Nofossil]

I see moisture meters on sale from $30 to up over $200. I assume the expensive ones are for kiln driers and woodworkers who need to know mc with some accuracy and precision. I'm guessing that one of the cheaper ones would be fine for firewood. Any recommendations?

I got mine from some guy in Hong Kong who was selling them on eBay.

 

[jebatty]

Keep in mind that moisture meters are of two types, pin and surface reading. The pin types often have different lengths of pins which your press or pound into the wood. Moisture is read between the pins. Is only accurate where the reading is taken, and does not read further depth into the wood. Very good for boards, might not be the best for logs. Surface reading can be scanned over the log to easily take readings at different locations, but accurate only 1-2" or so into the log. Coming in from both sides and you can get pretty accurate into a 4-5" log, beyond that not an accurate reading of log interior.

Surface type can be useful but like so many other things is a guide only. Best bet is to cut, split, stack and let wood dry 1 or more seasons. From other posts gassifiers do best on fairly dry wood (15-25% or so), and not as well on wetter wood. From personal experience mine does well on drier wood (10-15%) but the burn is hotter, which means adjusted draft control at least.

I think both types of meters have adjustment factors for the type of wood, ie, +/- reading depending on type of wood. Probably not too necessary to pay attention to this for normal heating purposes, but might be important for careful meaurement of performance purposes.

 

[RedRanger]

My moisture meter has the 2 pins (see my post under the Gear). If I am in doubt about a batch of wood, I resplit a few pieces and take the reading on the inside of the new splits. Sometimes even going so far as to drill a couple of tiny holes in which to insert the pins,little more work but it is accurate. So basically, re-splitting into smaller pieces and then testing seems to be the "key" if in serious doubt. Eric, I know what you mean, you can be burning wood from the same woodshed for weeks and weeks and then all-of-a-sudden, there appears to be some smouldering happpening with some of the pieces. Thats when it`s time for the good old moisture meter.

 

[Father John]

I too would be interested in recommendations as to which brand and where to buy a moisture meter. I have asked around local hardware stores, but no luck.

I think Eric is right about needing at least a basic ability to measure wood moisture, otherwise it is impossible to define our terms when we speak of "partly dry", or "rather wet" or "well seasoned" firewood.

 

[Bob Rohr]

knock a couple of pieces of wood together to get a good idea of moisture content. Dry wood makes a hollow crack sound. Wet wood more of a thud. The weight will also be a clue. I feel all wood needs to be split to 6" or less at the widest spot to assure it is dry.

Wet or damp wood emits steam when burned which dilutes the wood gases.

here is a moisture meter posted at www.woodheat.org. Looks a little hommade, but powerful

hr

 

[jebatty]

I too would be interested in recommendations as to which brand and where to buy a moisture meter. I have asked around local hardware stores, but no luck.

Wagner makes a good surface scanning type meter, which I use in my wood shop, also to test wood coming out of the solar dry kiln. Not cheap, tho.

 

[Nofossil]

For firewood, the pin type seems to be fine. I always split a piece an take a couple of measurements across the fresh surface, just pushing in the pins by hand. You get the hang of it quickly.

 

[Eric Johnson]

knock a couple of pieces of wood together to get a good idea of moisture content. Dry wood makes a hollow crack sound. Wet wood more of a thud. The weight will also be a clue. I feel all wood needs to be split to 6" or less at the widest spot to assure it is dry.

Wet or damp wood emits steam when burned which dilutes the wood gases.

here is a moisture meter posted at www.woodheat.org. Looks a little hommade, but powerful

hr

I've handled enough wood over the years to notice differences in moisture content. Weight works best for me. I'd just like to start putting some numbers to it. I was surprised at how much difference there is between the performance of "dry" vs. "very dry" wood. I think if I sold these things, in addition to the moisture meter, I'd throw in a couple fireboxes full of "very dry" wood--just so the customer would know what the potential is. It might be more than a year before he ever sees that level of performance again!

I think some people never burn dry wood. If you cut it green in the spring or summer, IME, it won't be down to 20 or 25% mc by the time the heating season rolls around. At least not with things like hard maple, beech, yellow birch, red and white oak. That's a huge obstacle in the growth path of wood gasification.

 

[Bob Rohr]

The OWF folks started that rumor about green or wet wood burning longer, thus more heat! I hear it all the time around here from the Hardy owners.

hr

 

[Eric Johnson]

I've heard that one many times, too. Makes no sense, but a lot of people seem to believe it. I've even heard old timers claim that green red oak burns hotter than dry oak. I guess it does eventually, when it gets torched off in your chimney liner. My favorite was the time I bought a triaxle load of hardwood in the dead of winter, some of which I intended to burn as soon as I could get it cut up. (This was about 15 years ago). The logger who sold me the wood suggested painting drain oil on the chunks before tossing them into the boiler. A unique approach, I'll give him that.

 

[antknee2]

This Timber Master moisture meter has a super easy calibration for different types of wood , it comes with a chart just move marker on the lcd display across abcbefghj. Some of the unsplit big old oak rounds I found in the woods that looked bone dry on the outside ,turned out to have 50-60 % moisture content after you split them in half and use the meter .PS this tool really impresses my customers when looking for a water leak inside finished sheet rock wall. Anthony

(broken link removed to http://www.inspectortools.com/prottim.html)

 

[barnartist]

Last year I bought a bit of corn to try in the Eko. Not shelled as it will fall through the nossles. This is a great way to see what a gasifier is capable of doing. BIG BIG FLAME. On the other hand, while I sit through this mild winter, I tried a fire with dry on the bottom and a really big pice of unsplit wood on top. This during those upper 40 degree days. Since I go idle anyway, why not. So my result is about a 15 hr burn with all the heat I need. Had I thrown in my good stuff I would have been around 10 hours. Now if I was storing my heat like I should, this would be a bad thing to do. The other obvious result is heavy tar and big ash peices at the bottom. So i'm really not sure if it hurts anything other than clean up, but my woodpile doesnt shrink as fast.
What does all of this mean? You can sit on wetter wood like the old guys say, but if you need some real thunder heat no.
Eric, I know some guys here that have Hardy's, youd swear thier house was on fire. Im guilty of some smoke too from the above, but nothing like those stainless boys.

 

[Hbbyloggr]

Eric,

Back to your original post, we use the " Lignomat mini ligno" in our firewood operation. 6-45% readings, very dependable for 5 yrs so far. Highly recommend.
Saw a couple on ebay for around 60.00

 

[Eric Johnson]

Thanks, Bill. That sounds about right to me. I really don't want to spend close to $200 and I don't want a bottom-of-the-line one, either. I can remember when only sawmills with dry kilns had Lignomat and Wagner moisture meters. Now the rest of us can feel like big shots.

 

[Bartman]

Eric,
I've got the same one that nofossil has, got it on eBay for $28 with shipping, came out of MN. The thing seems accurate enough, for the price, you can't beat it. Usually I have a pretty good feel for the seasoned wood, it usually has a "ring" to it when hit together. Down here we have mostly red oak, don't believe the crap about green red oak, the only thing it's good for is a fire extinguisher. Had a nice hot fire going last a couple of weeks ago, threw a few green pieces in came back two hours later, fire's out. The best burn however, has been from standing dead red oak, it's murder to cut and split though.

 

[Jags]

Eric, I own a cheapo version from Harbor Fr. Have used it for about 1.5 yrs now. It is a 2 pin style that has LEDs that light up at the appropriate reading for moisture. It feels like it was made by Playco, but the darn thing does work. I have found that I probably use it about 5 to 8 times a year, just to get the "feel" of whats going on in the drying process. For this type of application, and the limited use it gets I am kinda glad I didn't go for an expensive version.

 

[pybyr]

Eric- what type meter did you eventually end up getting, and how do you like it?

Thanks

 

[EForest]

Just this morning I received a moisture meter that I purchased from Amazon.com
$20 plus shipping. It looks the one in NoFo's pic but a different name I think (HQRP MD-4G)
I checked several chunks from ends and had readings from 0-18%.
Then I split a half dozen or so and was bummed to get readings between 18-36%
On the bright side I can expect better results from the beast next year when its all a lot drier.

 

[Piker]

The cheapo meters are good for firewood. Even if they aren't that accurate as to the actual moisture content, they should be relatively consistent between readings. Once you establish what readings burn best, you just go from there.

How long it takes to get your wood dry depends on a couple of factors. Species, where it's stacked, if it's covered, if it's in the sun, in the woods, in a field, where the wind blows, etc etc. etc. If you have access to the right location to store your wood, you can actually get it dry in a pretty short amount of time. Keep it up off the ground, under roof if you can. I like to keep about a cord ahead in the basement... during the winter, the dry air in the house dries the wood out a substantial amount in just a couple weeks.

I burned mostly ash and soft maple this year. Cut and split in august. Most of it is in the 25% and below range by the time it's sat in the basement for 2 weeks. Cut the logs around 18" and split fairly small. I had some hickory on that same load, and a little hard maple. All have been working well. The oak on that load is a pain in the butt to get dry, it sizzles a bit when I put it in, but is still working pretty well for me as long as i mix it. Some of it's over 35% moisture content.

gasifiers are definitely more fussy about wood moisture... but the little bit of pre-planning with regard to what your are going to burn is well worth the time and effort saved in ammasing huge quantities of wood.

saw this and thought it would be of interest to some of you. The old holz hausen...
(broken link removed to http://www.thechimneysweep.ca/6seasoningwood.html)

cheers

 

[Piker]

Just wanted to add that I do run a small fan on the wood in the basement. The added moisture in the house is welcome, and sometimes it even smells nice. Had some sassafras that made a very faint pleasant aroma in the whole house.

cheers

 

[pybyr]

saw this and thought it would be of interest to some of you. The old holz hausen...
(broken link removed to http://www.thechimneysweep.ca/6seasoningwood.html)

cheers

Thanks- I've actually built HolzHausens the prior two years (06 and 07) for my old wood/ hot air furnace.

They seemed to work moderately well- but- the south-facing open-sided, roof-covered woodshed along the south face of my barn seems to work even better- by a long shot. The sun bakes the wood, and the wind dries it, more consistently than an HH. And, unlike an HH, it does not fall over (each of my HH's, despite meticulous building, did an avalanche at some point).

 

[pybyr]

Just wanted to add that I do run a small fan on the wood in the basement. The added moisture in the house is welcome, and sometimes it even smells nice. Had some sassafras that made a very faint pleasant aroma in the whole house.

cheers

I _love_ the smell of sassafras wood- but it doesn't occur, at least naturally, here in VT. Maybe I should import one for my long-planned ridiculous informal arboretum that I want to do on the edge of my meadow. I'm probably borderline for it on climate zone, though. Here, at and near my place, even red oak is an exception that occurs only on sheltered south-facing hillsides.

 

[Piker]

I have never built a holz hausen myself... but the idea seems practical. I actually have a nice lean-to shed on the garage that's about 26x26 for storing wood. It's not "open" all the way around, but it has two 9'x10' high openings in it that allow quite a bit air to pass through. I generally just stack the wood up in rows spaced apart to allow air to circulate and I'm good.

I saw one guy who stacked a bunch of his big logs on end, right on the ground. It's like the moisture from the ground went right up into the logs through the end grain. Wettest bunch of junk i ever did see.

I do my best to educate my customers about firewood. When I get the time I have plans on dedicating an entire page to firewood on my website. There's actually a TON of misinformation out there about the subject. More than I ever dreamed. Most of it comes from dishonest salesmen selling wood boilers and stoves.

cheers

 

[pybyr]

My first "Holz" I did on the ground, the second I did on pallets, to get the wood off the ground and let air up through.

For wood outside and not under cover, they did OK, but my arrangement with the roof overhead but the southern exposure works _way_ better