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Firewood moisture content
Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. Tim -- Please don't feed the trolls |
Firewood moisture content
On 17 Mar 2019 15:28:44 GMT, Tim+ wrote:
Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. Tim In short No! A DMM cannot even measure damp accurately, there are too many variables. Density is your best bet. weigh a fresh log, measure it, plane it or cut it to increase the surface area, stick it in a microwave on defrost for a few hours, weighing it until there is no significant reduction in reading. Now you can do things by the ton if you wish using a winch and an FIBC, or if you want to get really technical go for the ureka thing on bathnight. Having got your start weight, just bide your time and weigh again in about two years if it's logs for a fire. Tip! If married the FIBC approach is desireable. If Married and bath night is a "social occasion" then the FIBC approach is mandatory AB |
Firewood moisture content
"Tim+" wrote in message ... Can you estimate this with an ordinary multimeter? Nope, it varies too much with the type of wood and what you do with the probes. If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. No, because it varies so much with the wood and it isnt just the distance that matters |
Firewood moisture content
On 17 Mar 2019 15:28:44 GMT
Tim+ wrote: Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? "Proper" moisture meters are just guessing, sometimes wildly. Take a representative bit of your firewood, weigh it accurately and stick it in an oven on low heat for a few days then weigh it again (after it has cooled). The difference is how much moisture it's lost (it probably won't be completely dry, but it will be mostly, probably). You could try measuring resistance before and after drying to give some indication, but it probably won't be very repeatable - apart from anything else you're only measuring the surface, unless you want to chop it into 10mm cubes and measure the whole lot in each three directions ... |
Firewood moisture content
On Sun, 17 Mar 2019 17:47:04 +0000, Rob Morley
wrote: On 17 Mar 2019 15:28:44 GMT Tim+ wrote: Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? "Proper" moisture meters are just guessing, sometimes wildly. Take a representative bit of your firewood, weigh it accurately and stick it in an oven on low heat for a few days then weigh it again (after it has cooled). The difference is how much moisture it's lost (it probably won't be completely dry, but it will be mostly, probably). Do you re-read your drivel? "Weigh it accurately" "Probably completely dry" The number of clowns posting to theis NG when they haven't a clue never fails to amaze me. You could try measuring resistance before and after drying to give some indication, but it probably won't be very repeatable - apart from anything else you're only measuring the surface, unless you want to chop it into 10mm cubes and measure the whole lot in each three directions ... Resistance means nothing. Forget it as far as wood goes. Oven drying isn't linear. "Probably wont be completely dry" is an uncertainty that can be removed for all practical purposes. To dry wood to the point where you have a "dry datum" needs a bit of certainty and it is readily achieved by increasing the surface area. Even then an assumption has to be made that the rest of the wood was of the same type, cut at the same time etc. But at least the representative sample has been verified. To verify the sample needs a number of measurements ideally, being a natural event the moisture loss will be exponential. AB |
Firewood moisture content
Rob Morley wrote:
On 17 Mar 2019 15:28:44 GMT Tim+ wrote: Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? "Proper" moisture meters are just guessing, sometimes wildly. Take a representative bit of your firewood, weigh it accurately and stick it in an oven on low heat for a few days then weigh it again (after it has cooled). The difference is how much moisture it's lost (it probably won't be completely dry, but it will be mostly, probably). You could try measuring resistance before and after drying to give some indication, but it probably won't be very repeatable - apart from anything else you're only measuring the surface, unless you want to chop it into 10mm cubes and measure the whole lot in each three directions ... There are probably tables to be found somehere that tell one the relationship between density of wood and its moisture content. It would be different for different species of course. -- Chris Green · |
Firewood moisture content
On Sun, 17 Mar 2019 19:19:44 +0000
Chris Green wrote: There are probably tables to be found somehere that tell one the relationship between density of wood and its moisture content. It would be different for different species of course. Also probably differs for timber grown in different places and/or at different times. |
Firewood moisture content
On Sun, 17 Mar 2019 18:44:07 +0000
Archibald Tarquin Blenkinsopp Esq wrote: Do you re-read your drivel? "Weigh it accurately" "Probably completely dry" Well yes, you eliminate possible error where you can, but accept that some things aren't absolute and take account of that. |
Firewood moisture content
Rob Morley wrote:
On Sun, 17 Mar 2019 19:19:44 +0000 Chris Green wrote: There are probably tables to be found somehere that tell one the relationship between density of wood and its moisture content. It would be different for different species of course. Also probably differs for timber grown in different places and/or at different times. Yes, but not wildly I shouldn't think. We're only talking about "dry enough to burn" here. -- Chris Green · |
Firewood moisture content
On Sun, 17 Mar 2019 20:14:06 +0000, Chris Green wrote:
Rob Morley wrote: On Sun, 17 Mar 2019 19:19:44 +0000 Chris Green wrote: There are probably tables to be found somehere that tell one the relationship between density of wood and its moisture content. It would be different for different species of course. Also probably differs for timber grown in different places and/or at different times. Yes, but not wildly I shouldn't think. We're only talking about "dry enough to burn" here. Easy to do it right if you are going to embark on the procedure. From personal experience misjudgement of when wood was dry enough to burn just relieved me of 2,300 Euro It was a lot of wood and it wasn't much over a year old, so I have only one person to blame :-( AB |
Firewood moisture content
Archibald Tarquin Blenkinsopp Esq wrote:
On Sun, 17 Mar 2019 20:14:06 +0000, Chris Green wrote: Rob Morley wrote: On Sun, 17 Mar 2019 19:19:44 +0000 Chris Green wrote: There are probably tables to be found somehere that tell one the relationship between density of wood and its moisture content. It would be different for different species of course. Also probably differs for timber grown in different places and/or at different times. Yes, but not wildly I shouldn't think. We're only talking about "dry enough to burn" here. Easy to do it right if you are going to embark on the procedure. From personal experience misjudgement of when wood was dry enough to burn just relieved me of 2,300 Euro It was a lot of wood and it wasn't much over a year old, so I have only one person to blame :-( However you only need to keep it for a while and then it's OK to burn. -- Chris Green · |
Firewood moisture content
On 17 Mar 2019 15:28:44 GMT, Tim+ wrote:
Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. Pretty much. Make upa jig to hold the DMM probes a fixed distance apart and measure a few logs that have been inside next to the stove (that's been on or in a room that is heated) for a few weeks. They'll be "dry". Compare those numbers with the numbers you get from logs in the outdoor log store. You'll get a "feel" for what is "dry" and what is "not so dry", which is all a "firewood moisture meter" in effect does. -- Cheers Dave. |
Firewood moisture content
Tim+ wrote:
Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. Tim Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. |
Firewood moisture content
Do not a lot of them actually need a specific contact area as well or even a
probe that one inserts into the substance? Brian -- ----- -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! "Tim+" wrote in message ... Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. Tim -- Please don't feed the trolls |
Firewood moisture content
On Mon, 18 Mar 2019 16:00:40 +1100, FMurtz wrote:
Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. 'cause it takes lot of energy to vapourise water. Energy (heat) that goes straight up the chimney entrained in the the water vapour. -- Cheers Dave. |
Firewood moisture content
FMurtz wrote:
Tim+ wrote: Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. Maybe, but environmental legislation is on it way to control the burning of damp wood. Chris -- Chris J Dixon Nottingham UK Plant amazing Acers. |
Firewood moisture content
On Monday, 18 March 2019 11:05:12 UTC, Chris J Dixon wrote:
Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. Maybe, but environmental legislation is on it way to control the burning of damp wood. Legislating for something that is difficult to measure easily is going to be interesting. John |
Firewood moisture content
FMurtz wrote:
Tim+ wrote: Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. Tim Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. Reduced heat output and increases creosote/tar deposition in your chimney. Not always easy to sweep out. Less than 20% moisture seems to be a pretty universal recommendation for all wood burners. Tim -- Please don't feed the trolls |
Firewood moisture content
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Firewood moisture content
On Mon, 18 Mar 2019 16:00:40 +1100
FMurtz wrote: Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. AIUI can cause problems with deposits/corrosion in the flue. |
Firewood moisture content
On 18/03/2019 19:26, Rob Morley wrote:
On Mon, 18 Mar 2019 16:00:40 +1100 FMurtz wrote: Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. AIUI can cause problems with deposits/corrosion in the flue. yes, it can. Hence the move to insulated flues. -- "Women actually are capable of being far more than the feminists will let them." |
Firewood moisture content
On 18/03/2019 05:00, FMurtz wrote:
Tim+ wrote: Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. Tim Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. Depends how much you enjoy spectacular chimney fires when the tars and oils that condense out in the flue decide to catch light. Wet wood wastes a lot of energy boiling off its water content to no good end. Most people round here have a wood burner to heat their home not to just look pretty. It makes sense to season timber for burning at least 2 years and leave it to warm by the fireside for a while prior to burning. -- Regards, Martin Brown |
Firewood moisture content
On 18/03/2019 05:00, FMurtz wrote:
Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. Damp wood results in condensation in the flue. Combined with the products of the lower temperature combustion - which will include tars - this can be a bit nasty for the poor old flue. Andy |
Firewood moisture content
On 2019-03-18 2:41 p.m., Vir Campestris wrote:
On 18/03/2019 05:00, FMurtz wrote: Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. Damp wood results in condensation in the flue. Combined with the products of the lower temperature combustion - which will include tars - this can be a bit nasty for the poor old flue. Andy but the flames light up the yard so nicely |
Firewood moisture content
On 18/03/2019 21:50, % wrote:
On 2019-03-18 2:41 p.m., Vir Campestris wrote: On 18/03/2019 05:00, FMurtz wrote: Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. Damp wood results in condensation in the flue. Combined with the products of the lower temperature combustion - which will include tars - this can be a bit nasty for the poor old flue. but the flames light up the yard so nicely A wood tar chimney fire tends to burn with a pale blue flame and a moderate amount of noise. Anyone burning wet wood deserves what they get. They are likely not to bother sweeping the chimney either. -- Regards, Martin Brown |
Firewood moisture content
On 19/03/2019 08:34, Martin Brown wrote:
On 18/03/2019 21:50, % wrote: On 2019-03-18 2:41 p.m., Vir Campestris wrote: On 18/03/2019 05:00, FMurtz wrote: Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. Damp wood results in condensation in the flue. Combined with the products of the lower temperature combustion - which will include tars - this can be a bit nasty for the poor old flue. but the flames light up the yard so nicely A wood tar chimney fire tends to burn with a pale blue flame and a moderate amount of noise. Anyone burning wet wood deserves what they get. They are likely not to bother sweeping the chimney either. Oh I burn wettish wood when I have to, but I keep my chimneys clean these days. Miust have had about 4-5 chimney fires in my time Apropos of not much I have a vivid recollection of walking down the steet at night in Belsize park and seeing the wall of the flat I was sharing growing red hot...from an open fire, burning skip rubbish.. -- "Nature does not give up the winter because people dislike the cold." Confucius |
Firewood moisture content
Martin Brown wrote:
On 18/03/2019 21:50, % wrote: On 2019-03-18 2:41 p.m., Vir Campestris wrote: On 18/03/2019 05:00, FMurtz wrote: Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. Damp wood results in condensation in the flue. Combined with the products of the lower temperature combustion - which will include tars - this can be a bit nasty for the poor old flue. but the flames light up the yard so nicely A wood tar chimney fire tends to burn with a pale blue flame and a moderate amount of noise. Anyone burning wet wood deserves what they get. They are likely not to bother sweeping the chimney either. Chap down the road burns quite a lot that he gathers on his daily walk through the wooded area around here, after winds like we have had this week he takes a wheel barrow and a saw. To be fair to him he has his own brushes and does the the lined flu once a month. Larger limbs and branches he does turn into logs and keeps them for two years and some of that he has bought from the landowner where it it has fallen but he reckons that the daily collection of smaller stuff amounts to about a third of his consumption with consequent savings. Being retired he had the time and it is almost a hobby for him, before he was a delivery driver for a builders merchant and burnt a lot of pallets so their dryness counteracted some of the green branches when mixed. His moan now after being retired for 3 years is that he has now moved into the nobody down there knows me anymore category and they wont let him have any now. So for the first time for years he got some coal product in . I always thought was the worst combination of all due to the different substances condensing out and creating quite a corrosive mix but he is not the sort of bloke to listen to things like that, and with a wife who has just had a stroke needs to keep the house warmer and has less time to gather his wood. This is a country area so it is not too bad but the powers that be can legislate against various fuels as much as they like but if policies make electricity etc unaffordable we will see a lot more of people making homemade stoves and opening up long disused chimneys and trying to keep the use of them clandestine while they burn rubbish from skip diving etc in towns and cities. That will cause a lot of problems and fires and whatever the authorities say if they cant stop visiting workers living in garden sheds turned into bunk houses they wont be able to stop every illegal fireplace. GH |
Firewood moisture content
In message , The Natural Philosopher
writes On 19/03/2019 08:34, Martin Brown wrote: On 18/03/2019 21:50, % wrote: On 2019-03-18 2:41 p.m., Vir Campestris wrote: On 18/03/2019 05:00, FMurtz wrote: Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out Damp wood results in condensation in the flue. Combined with the products of the lower temperature combustion - which will include tars - this can be a bit nasty for the poor old flue. but the flames light up the yard so nicely A wood tar chimney fire tends to burn with a pale blue flame and a moderate amount of noise. Anyone burning wet wood deserves what they get. They are likely not to bother sweeping the chimney either. Oh I burn wettish wood when I have to, but I keep my chimneys clean these days. Miust have had about 4-5 chimney fires in my time Apropos of not much I have a vivid recollection of walking down the steet at night in Belsize park and seeing the wall of the flat I was sharing growing red hot...from an open fire, burning skip rubbish.. Not advice or recommendation but my log burner has been in Winter use since 2009 without a chimney clean. 7" insulated liner. I have looked down the top and shone a camera/light up the bottom and found about 5mm of grey *fluff* attached to the walls. There seems little point in brushing this out. Mind, I have only ever burned furniture grade Oak:-) -- Tim Lamb |
Firewood moisture content
On Mon, 18 Mar 2019 17:50:59 +0000, The Natural Philosopher wrote:
You can walk around towns these days and smell coal buring in open fires. Still winters day and there is a thick pall of coal smoke sitting over Middleton-in Teesdale. No mains gas, nearly every house has a coal fire... -- Cheers Dave. |
Firewood moisture content
On 19/03/2019 09:52, Tim Lamb wrote:
In message , The Natural Philosopher writes On 19/03/2019 08:34, Martin Brown wrote: On 18/03/2019 21:50, % wrote: On 2019-03-18 2:41 p.m., Vir Campestris wrote: On 18/03/2019 05:00, FMurtz wrote: Why does it matter? I have a wood heater and it does not matter how* wet the wood is once you have started the fire, It dries out Damp wood results in condensation in the flue. Combined with the products of the lower temperature combustion - which will include tars - this can be a bit nasty for the poor old flue. but the flames light up the yard so nicely *A wood tar chimney fire tends to burn with a pale blue flame and a moderate amount of noise. Anyone burning wet wood deserves what they get. They are likely not to bother sweeping the chimney either. Oh I burn wettish wood when I have to, but I keep my chimneys clean these days.* Miust have had about 4-5 chimney fires in my time Apropos of not much I have a vivid recollection of walking down the steet at night in Belsize park and seeing the wall of the flat* I was sharing growing red hot...from an open fire, burning skip rubbish.. That is impressive. I have seen it discolour the wallpaper in bedrooms. Not advice or recommendation but my log burner has been in Winter use since 2009 without a chimney clean. 7" insulated liner. I have looked down the top and shone a camera/light up the bottom and found about 5mm of grey *fluff* attached to the walls. There seems little point in brushing this out. Mind, I have only ever burned furniture grade Oak:-) Mine burns mostly dry wood and some coal. The grate is multi-fuel. I sweep it once a year before serious use. It has a 5" insulated liner. Only ever get grey fluffy stuff but if you leave it for too long one day you will get an uncontrolled collapse of the stuff down the pipe. -- Regards, Martin Brown |
Firewood moisture content
On 18/03/2019 21:50, % wrote:
On 2019-03-18 2:41 p.m., Vir Campestris wrote: Damp wood results in condensation in the flue. Combined with the products of the lower temperature combustion - which will include tars - this can be a bit nasty for the poor old flue. but the flames light up the yard so nicely We have a thatched roof. I'll use dry wood thanks! Andy |
Firewood moisture content
On Monday, 18 March 2019 05:00:53 UTC, FMurtz wrote:
Tim+ wrote: Can you estimate this with an ordinary multimeter? If so, what sort of figures would indicate a moisture level below 20%? I assume meters made for the purpose just measure resistance across a fixed distance, but I could be wrong. Tim Why does it matter? I have a wood heater and it does not matter how wet the wood is once you have started the fire, It dries out quickly. It also produces a lot less heat and more air pollution. (Any water present has to be evaporated off before it can burn.) Tars up the chimney and increases chance of chimney fire. |
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