How dry is dry enough?

[stoveliker]

Okay. I know for a fact that my explanation of how they work above is true.

How this plays out with the numbers is evidently influenced by other factors that affect the values more. E.g. how deep the pins are.


Bottom line: they tell you "good enough" or not, but here it is surely good enough.

 

[JRHAWK9]

I'm just looking for some consistency. I push mine is as far as I can so they stay on their own, with red oak that is not very far.

Just tested two more red oak splits, after I resplit them. These were all C/S/S in spring of '15! I do split mine on the larger side though.

Like I said, mine are consistently ~4% different every time.

 

[stoveliker]

The general tools one should have a calibration spot in the lid that goes over the pins.
I find that when I measure a few times, the values easily differ by 0.5-1%, so having *exactly* 4% difference each time is a rather peculiar coincidence.

The manual says it has an accuracy of plus minus 2%. Given that they note this right after the 3-50% MC range, I think this is 2% in MC value (not 2% of the measured value). I.e. 16% read out is consistent with something in the 14-18% range (and not 16% +/- 0.32%).

So putting too much emphasis on the exact value is not appropriate anyway.

Hook the 4-pin one up to the resistor in the testing circuit in the general tools one (will require some finagling) to see if the calibration is indeed off - I would not do that, as it's not worth the time. But if you're curious, that's the way to go. Test both with a known resistance.

 

[Split]

I used my digital multimeter on several splits plus my mm. They both said below 20%. All I know is this year my splits take off within 10 seconds. They sound dry too.

 

[Split]

I'm just looking for some consistency. I push mine is as far as I can so they stay on their own, with red oak that is not very far.

Just tested two more red oak splits, after I resplit them. These were all C/S/S in spring of '15! I do split mine on the larger side though.

Like I said, mine are consistently ~4% different every time.

View attachment 301025



View attachment 301024

That's seven years of drying css? And still only at 20%? That doesn't seem right.

 

[clancey]

The sad part with my thinking or opinion is a better type of meter could be invented to make it a lot easier to test the moisture in wood. Disappointed in the ones I tried so far and on one I bent the four prongs on it so bad that I got "fed up" and threw it away. Not a expert on this but I found measuring wood for moisture very frustrating to say the least..clancey

 

[Garbanzo62]

I wanted to get the Stihl. How is it?

It is pretty simple to use. One button, I have nothing to compare it to, but for $25 and a reputable name I figured it was worth a shot. It is Small, so it easily fits into a shirt or pants pocket. It is about 2 match boxes long, one wide and two high. Has setting for plaster and cardboard and Outside temp. Range is 6% to 40% above or below you get OL for the reading. It shuts off after like 10 seconds. Came with button batteries installed, just had to open the case and remove the plastic tab that prevented batter contact.

 

[Garbanzo62]

So Bottom Line.. How wet is too wet? If I mix 1 -24% split with 3 - 13% splits is that OK? If so, what is the max percentage you would ever put into a stove? (Can't wait for the opinions on this).

 

[stoveliker]

There are no "rules". My *opinion* is:
-above 25% is too wet
-I would not put stuff in above 25%.
-I think it would be fine to mix one 24% with three 13% splits.

 

[BIGChrisNH]

The low 20% range is fine, at least in my opinion. I've gotten through winters with some of the splits being 24% or so and just mixing it with drier stuff. I didn't have any problems doing that, but I did sweep the chimney in later January. Some of my splits always hiss even after 3 years CSS, there doesn't seem to be a perfect recipe in New England for drying wood perfectly outdoors unless you build solar kilns. Some of my stack locations have a backside that doesn't get much sun or wind, there's always some logs in there that have a wet end. Most of other splits sound like bricks when you bang them together, which means they're nice and dry.

 

[NickW]

Species makes a big difference too. Low 20's ash burns pretty well, low 20's oak or pine not nearly as good...

 

[stoveliker]

That is true. But how easily it burns does not matter for how much heat you get out of it (vs waste it by boiling water thru the flue) and how much deposits you put into your chimney.

Burning wet ash is still burning wet wood, even if it burns well (which, admittedly does provide some heat for pushing the water out of the flue).

 

[NickW]

That is true. But how easily it burns does not matter for how much heat you get out of it (vs waste it by boiling water thru the flue) and how much deposits you put into your chimney.

Burning wet ash is still burning wet wood, even if it burns well (which, admittedly does provide some heat for pushing the water out of the flue).

Absolutely correct. Not saying it's ideal, but if I gotta burn low 20's wood it's gonna be ash.

For the same reasons ash dries quickly css, it does the same in the stove. Key is to get the stove and flue hot fast to minimize deposits, then don't cut the air too fast. You can have secondaries and still be boiling out moisture. Cutting the air too much too fast will smolder the fire and it's harder to get back going again once the outside is charred and there's still moisture inside. Wouldn't be fun with oak...

 

[patrickk222]

OK, so I think I have enough wood to make it through the winter, but my stacks are not as large as I would want. Due to an injury and illness, I am just getting to cutting to bolster my stacks. I'm fortunate that my neighbor lets me cut dead wood on his 10 acres. I harvested some dead Ash and dragged the 20' logs to my processing area. Moisture readings are between 16-17% and I'll get them CSS this weekend. Will this wood be good for this winter, or should I let it season over the winter, it will make a difference in how I stack it. Thank-you.

thats pretty much perfect imo .... and i reckon about 20%mc is the standard for dry or not

 

[brenndatomu]

There are no "rules". My *opinion* is:
-above 25% is too wet
-I would not put stuff in above 25%.
-I think it would be fine to mix one 24% with three 13% splits.

If you think about it for a minute, say you load 50 lbs of wood in the stove that is 20% MC (that is considered "dry" right?) 10 lbs of that is water...and at 8.34 lbs per gallon, that's almost 1.25 gallons of water you just loaded into the firebox! Sounds like a proper sauna to me...let alone what it would be like with 20% + MC wood!

 

[brenndatomu]

They sure did give you a pricey meter with your HM!!

"Give" is a pretty strong word to use when describing something that came with a new OWB these days!

 

[stoveliker]

If you think about it for a minute, say you load 50 lbs of wood in the stove that is 20% MC (that is considered "dry" right?) 10 lbs of that is water...and at 8.34 lbs per gallon, that's almost 1.25 gallons of water you just loaded into the firebox! Sounds like a proper sauna to me...let alone what it would be like with 20% + MC wood!

I have thought about this. The point is that modern stoves do reasonably well with 20 pct mc wood.

And it's worse than you thought: burning a pound of wood creates about half a pound of water. So your 50 lbs of wood at 20 pct has to push 25+10=35 lbs of water up the flue.

Now that's 35 reasons to keep the flue above water condensation temperature!

 

[Ctwoodtick]

FWIW, those General meters (at least mine) reads consistently low by about 4%. The orange one on the right matches what someone else's meter shows and theirs matches what an EPA testing agency uses. I have stopped using the General and only use the four pronged orange one.


View attachment 300853

I find that my orange meter is a couple points higher as well.

 

[brenndatomu]

And it's worse than you thought: burning a pound of wood creates about half a pound of water. So your 50 lbs of wood at 20 pct has to push 25+10=35 lbs of water up the flue.

Not following you on this...

 

[stoveliker]

The hydrogen in organic compounds will react with the oxygen to form water.

Just as water and CO2 come out of the tailpipe of your vehicle.

 

[brenndatomu]

The hydrogen in organic compounds will react with the oxygen to form water.

Just as water and CO2 come out of the tailpipe of your vehicle.

Ah, gotcha

 

[stoveliker]

To make clear why dry wood still is important, the water formed does not need to be evaporated. It forms in the gas phase hot (and releasing energy when forming).

The big energy consumption of wet wood is the latent heat put in evaporating the wetness that should have been dried out of it. That robs the fire of energy it needs to keep combusting efficiently.

 

[ozarkoak]

I'm a simple man. Wood burns hot? Wood good. Wood smoulders and me cold? Wood bad. Even the most precision and expensive tools (oscilloscopes, torque wrenches, volt meters) have a +- percentage. I doubt any $30 moisture meter can be trusted other than wood wet, wood dry. IMO the only way to guarantee your wood is dry enough is to season it yourself. No smoke, starts easy, burns hot, burns complete, no water dripping out the ends, stack stays clean anything else IMO is just bragging rights. My wood for this year is around 19-20% on the General meter, room temp fresh split. I have read in this thread that the General can be 4% off. according to some that would mean my 20% wood is 24% and shouldnt be burned. I just burned some during the last cold snap and it lit with one match, burned to dust and heated my home to underwear only level. I think the biggest use of the moisture meter is to see where you are starting and how much progress you are making and still that would be ball park. Type of wood, temperature, meter calibration, are all potentials for inaccuracy. I would bet $1000 that there have been people burning wood they think is 18% and due to the inaccuracy of the meter the wood is actually in the low 20s. Trust me you will know if your wood is too wet to burn properly. You will be cussing, cold and stinking like a wildfire.

 

[stoveliker]

Exactly.

just burned some during the last cold snap and it lit with one match, burned to dust and heated my home to underwear only level.

That is good wood.

 

[Garbanzo62]

I'm a simple man. Wood burns hot? Wood good. Wood smoulders and me cold? Wood bad. Even the most precision and expensive tools (oscilloscopes, torque wrenches, volt meters) have a +- percentage. I doubt any $30 moisture meter can be trusted other than wood wet, wood dry. IMO the only way to guarantee your wood is dry enough is to season it yourself. No smoke, starts easy, burns hot, burns complete, no water dripping out the ends, stack stays clean anything else IMO is just bragging rights. My wood for this year is around 19-20% on the General meter, room temp fresh split. I have read in this thread that the General can be 4% off. according to some that would mean my 20% wood is 24% and shouldnt be burned. I just burned some during the last cold snap and it lit with one match, burned to dust and heated my home to underwear only level. I think the biggest use of the moisture meter is to see where you are starting and how much progress you are making and still that would be ball park. Type of wood, temperature, meter calibration, are all potentials for inaccuracy. I would bet $1000 that there have been people burning wood they think is 18% and due to the inaccuracy of the meter the wood is actually in the low 20s. Trust me you will know if your wood is too wet to burn properly. You will be cussing, cold and stinking like a wildfire.

If the General is 4% off it is possible that your 20% is really16% . My Stihl MM says the accuracy is Reading < 30% + / - 2% Reading >= 30% + / - 4%. I do notice that when I put in the meter many times it initially reads one value and then changes to a different one.