With our new FPX 36 install we received a moisture meter (a moving LED model, never seen this anywhere else). It seems to read very much on the dry side, but I have nothing to compare it to. The go/no-go test is two fingers, which reads around 15-18%. Oak that has been seasoning for a couple of years usually doesn't even get it to the first (7%) LED. A split of a small cedar log on the property, that had been sitting outside for who knows how long, showed 10-11%. From all I read, these readings sound pretty low. One possible issue is that the manual says drive the pins 6mm into the wood. Well, that is simply impossible, either into the ends or into the split side. Maybe 1mm is all I can get. No idea how much that will affect the readings. Any thoughts on all this?
Do I have the driest wood in the world, or a bad moisture meter?
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Poindexter
Minister of Fire
On mine with crescent of leds that light up sequentially the unit reads higher and higher as the pins are buried deeper and deeper.
Dont bother measuring the end, its meaningless.
Dont bother measuring the end, its meaningless.
brenndatomu
Minister of Fire
Make sure the pins are screwed on all the way. My meter pins were loose And it would read lower moisture
Haven't seen an inexpensive MM yet that had pins that were possible to be driven in or pushed in much over 2mm, cases and the pin mounting there in are not robust enough. Might want to read the manual to see if there is a re-calibration procedure as that one is reading way off.
As a side note a lot of these are calibrated to read furniture type wood which is a different scale than fire wood. Kiln dried type wood- furniture grade should fall in the 8-12% range, right out of the kiln with out any ageing about 6%. I would get a fresh battery before anything else- readings are very dependent on that.
a little tip , 2 nails small piece of plastic to pass nails through that will hold them at the same spacing as the pins on meter - now you drive those in too the recommended depth and the check moisture by touching pins to nail heads. the slight difference/ resistance of the nail to pin contact is immaterial.
As a side note a lot of these are calibrated to read furniture type wood which is a different scale than fire wood. Kiln dried type wood- furniture grade should fall in the 8-12% range, right out of the kiln with out any ageing about 6%. I would get a fresh battery before anything else- readings are very dependent on that.
a little tip , 2 nails small piece of plastic to pass nails through that will hold them at the same spacing as the pins on meter - now you drive those in too the recommended depth and the check moisture by touching pins to nail heads. the slight difference/ resistance of the nail to pin contact is immaterial.
Thanks, the two nails trick would be an easy way to get a rough calibration for this meter. Just make a measurement with the meter, then drive two nails into the pin-holes and make a new measurement. Finally, check that measurement with the first measurement.
Beyond that (and checking the battery), I think I see another meter or two in my future.
NateH
Member
So you just rely on the hollow knock test? Like people have done for maybe the last 50,000 years?
NateH
Member
Right now I don't have to... I have mostly Ash and a little maple and cherry but no wood burner. My installation plans got put on hold... big time. It's a long story. But I'm always hunting wood.
This reminds me that I need to find mine. If not just to take the battery out. Where did I put that stupid thing? God thats going to bother me now.
Once you are about 3 years ahead on a rotation cycle most of us pretty much ignore moisture meters. On the other hand if you are buying cord all ready split ( of course advertised as dry) it is your best defense to not get snookerd by load of wet firewood. By the way if it is advertised as kiln dried, it is a good idea to slice a split open and check it on fresh inside face- most kilns operations are for de-bugging not drying as that takes way more than a few hours at x heat. ( like 30 days) . if you question this statement look it up. I have a customer who builds rustic furniture- commercial operation - 30 days is their number in their Kilns. Most of the assembled furniture is less than 5 " in diameter of any one cross section so increasing the cross-sectional size would also increase the kiln time. Kiln time = $ spent. Firewood is not a high profit item and for most of the bigger suppliers it is an out growth of there primary service. Like the millworks not too far from here that makes pellets from their scrap- cost effective reduction of waste that otherwise would be a cost to dispose of at the landfill and possibly provide a bit of income after subtracting associated costs of pellet production less the disposal fees.
i pulled mine out and tested a piece of dead elm that was just taken down and it measured 25%. I measured some russian olive and it came in at 17%. I measured some honey locust that was cut in september, and split last night.... it measured 34%. The box elder that was cut down last week measured 92%. i did not even think that was possible!
Handsonautotech
Burning Hunk
After having my moisture meter for a while now and working the wood pile a bit, I am starting to get a feel for what is ready to burn and what is not just by weight. It is not 100% accurate but close enough that I end up with a good mixed pile to take into the house for immediate use. Maybe I have some genetic advantage passed onto me through those 50,000 years by the folks that did not die from chimney fires?
Hasufel
Feeling the Heat
I have a cheapo Pittsburgh mini-meter that seems to work well on hardwoods but I'm not so sure on pine. I have plenty of oak that's still obviously wet inside and the meter shows it being in the 60% +/- range. On the other hand I just split some pine that's been dead for about 4 years (2 standing & 2 lying) and it got no higher than 21%. I'n not used to burning pine but this still seemed a bit damp, though not nearly in the oak category. It's definitely lighter than hardwoods but it has that "fresh 2X4" smell when split and the insides still seemed supple. My meter has no ability to correct for hard vs. soft woods, but does anyone know of a rough rule of thumb that I can apply in a case like this?
CheapBassTurd
Minister of Fire
I'm Cheap but not that "cheap".
The plan is to train myself to never need one.
The learning curve isn't horrible as one can get a feel on a fresh split.
Sound too. "If it knocks, it goes to the the firebox."
Mom was a stover as a kid in the 1940's. Learnin' old school here.
(to be fair she's insane. At 81 she just went down to two jobs to relax more.)
The plan is to train myself to never need one.
The learning curve isn't horrible as one can get a feel on a fresh split.
Sound too. "If it knocks, it goes to the the firebox."
Mom was a stover as a kid in the 1940's. Learnin' old school here.
(to be fair she's insane. At 81 she just went down to two jobs to relax more.)
Sprinter
Minister of Fire
Sounds like the meter is reading low. What model meter is this? Placing the pins on your palm should read about 35%. This test is more reliable than it may seem. Is this a two-pin type meter?
Make sure to split the wood just before checking. Check on the face of the fresh split part in the middle.
Sprinter
Minister of Fire
For pin-type meters usually used for firewood, this chart shows corrections for different species. Note that Douglas Fir is the standard value.
http://www.moisturemetersdelmhorst....Correction-Table-Pin-Type-Moisture-Meters.pdf
It was published by Delmhorst but should apply to any pin-type meter.
Hasufel
Feeling the Heat
Excellent resource, thanks! I'm surprised there's not more variation between different species. I would not have guessed that red oak was identical to doug fir across the board...
Sprinter
Minister of Fire
I didn't notice that about fir and Red Oak. Temperature also affects the readings. Also, pin-type meter readings can become a little inconsistent much above 25% or so. But for us, all that is okay because a few % points is not really that important. There can be regional variations as well within species. The figures in these charts are averages I believe.
What I take from charts like this is that for firewood, the differences are interesting, but we shouldn't get hung up on precision. All we need to know is whether the wood is okay to burn in our stoves. For that purpose, a relatively small coefficient of variation is not a problem. If you are laying flooring or something like that, it may be a greater issue.
Your observation regarding Douglas Fir and Red Oak also makes it clear that it's not as simple as hardwood vs softwood. Good catch.
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