Moisture Meter
- Thread starter Gasass
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
- Status
TreePointer
Minister of Fire
Technically you would want to calibrate it within the RANGE (not just a couple data points around 20%) of moisture content (MC) typically found in firewood, say from 10% to 50%.
There are a couple ways to do this:
1. calibrate with standards of known MC (expensive laboratory samples)
2. calibrate against readings from known accurate moisture meter. (if you had one of those, you wouldn't be asking, lol.)
Without either of those, it's difficult to get a good calibration at home. We can, however, take some measurements that can give us some confidence that the MM is functioning properly within the range of interest for firewood.
* Find some old 2X4 that's been sitting in a dry place for years (maybe in your attic). It's MC should be around 10%.
* Measure in some 2 year seasoned ash (or what ever species you have). Look for 20% (+/-5%) MC.
* Measure in a piece of freshly cut ash (or what ever species you have).
That should give you three different readings with which to start. You can add more readings from different samples, say 6 month oak, 1 year oak, 2 year oak, etc. The point is that the more readings you take, the more data points you will have to increase your confidence in the meter.
There are a couple ways to do this:
1. calibrate with standards of known MC (expensive laboratory samples)
2. calibrate against readings from known accurate moisture meter. (if you had one of those, you wouldn't be asking, lol.)
Without either of those, it's difficult to get a good calibration at home. We can, however, take some measurements that can give us some confidence that the MM is functioning properly within the range of interest for firewood.
* Find some old 2X4 that's been sitting in a dry place for years (maybe in your attic). It's MC should be around 10%.
* Measure in some 2 year seasoned ash (or what ever species you have). Look for 20% (+/-5%) MC.
* Measure in a piece of freshly cut ash (or what ever species you have).
That should give you three different readings with which to start. You can add more readings from different samples, say 6 month oak, 1 year oak, 2 year oak, etc. The point is that the more readings you take, the more data points you will have to increase your confidence in the meter.
Last edited:
TreePointer
Minister of Fire
That proves the MM is good at measuring in the "low 30's." What if the MM measures everything in the low 30's? That's why we need to test within a RANGE of samples with different MC.
Lumber-Jack
Minister of Fire
Measure a piece of kiln dried wood that is known to be dry, it should measure between 0-5%, then measure a piece of cord wood from a green tree, it should measure >30%. If you get those measurements then likely when you are getting any measurements on your other cord wood and get any measurements in between it will be close enough. Just remember, a moisture meter is not an exact tool, just like the gas gauge on your car is not exact, they just give you a far better idea of what's going on then guessing.
You'll get those who will say you don't need a moisture meter, all you have to do is just let your wood sit for 3 years, then you know it's dry. To me that's kind of like saying you don't need a gas gauge on your car, all you have to do is drive it till it stops, then you'll know it's empty. Sure, that works, but using a gauge just seems smarter.
You'll get those who will say you don't need a moisture meter, all you have to do is just let your wood sit for 3 years, then you know it's dry. To me that's kind of like saying you don't need a gas gauge on your car, all you have to do is drive it till it stops, then you'll know it's empty. Sure, that works, but using a gauge just seems smarter.
paul bunion
Minister of Fire
The moisture meter that I have has a 1 M ohm test resistor built into the cap, it reads 27%. The distance between the prongs would need to be the same for that to be accurate on a different meter.
mark cline
Minister of Fire
You body should be just right to burn by next Fall.
CenterTree
Minister of Fire
bigbarf48
Minister of Fire
ErikR
Burning Hunk
Your hand is very dry. Most are in the low 30's. Maybe you meter is reading low.
I figure my meter is pretty close. If the meter reads under 20, I find the wood burns great, if I burn wood with a reading over 25, it is a pain to burn and I have to babysit the stove.
Makes sense?
Even if your meter is off, just keep track of what readings burn well and what don't. The actual number is not as important as knowing what is burnable and what needs more drying time.
In most cases, a lot of us can tell moisture content by the weight of the wood. With some wood, such as cherry, the more it smells great, the more moisture it has.
Makes sense?
Even if your meter is off, just keep track of what readings burn well and what don't. The actual number is not as important as knowing what is burnable and what needs more drying time.
In most cases, a lot of us can tell moisture content by the weight of the wood. With some wood, such as cherry, the more it smells great, the more moisture it has.
I got 35 on some fingers and 25 on others. I get low 30's on my palm too but it depends upon how long I leave it there and how hard I press, the reading keeps climbing. Maybe hitting blood - or diesel fuel.
I was under the impression from somewhere on this forum that you really need to push it hard into the middle of a fresh split.The readings will be quite different on mine. Makes sense.
I was under the impression from somewhere on this forum that you really need to push it hard into the middle of a fresh split.The readings will be quite different on mine. Makes sense.
mark cline
Minister of Fire
My fingers read 20-22% , my butt reads 28%................. just thought you 'd want to know.
- Status
