Firewood - water content

[Mick Stockbridge]

I,ve never seen a moisture meter for wood,but if they are anything like moisture meters for detecting osmosis in fibreglass boats I would,nt trust them. Its so simple, stack you,re wood properly so the prevailing winds whistle through and the bark holds off the rain. After two years you,ll feel the difference in weight alone, split some and you,ll see it,s dry, if you,re still in doubt put a split piece to you,re upper lip and you will feel any moisture......Start saving those 5 and 6 inch pieces that you would normally put through the chipper and you,ll soon have enough for a good turnaround.

[firewoodman]

today i cut and split 16" diam pine, 7' long which had been stacked like stockers said, result, wet as the day i put it there.

2yr old beech, lime, willow, sycamore...the same as above, nice and dry

3 yr old poplar... same as the pine

4 yr old oak...... as above

suppose it depends on diam and species,

usually all mine is split as soon as it arrives at the yard or asap, but now i am very desperate for any dry wood as are my customers

[Mick Stockbridge]

today i cut and split 16" diam pine, 7' long which had been stacked like stockers said, result, wet as the day i put it there.suppose it depends on diam and species,/QUOTE]

 

It also depends on the length. I handball all my wood so its relatively small when stacked.

[firewoodman]

if its like the stuff in your avatar then its pretty easy to do so, but it is difficult to get it all that diameter when you process huge volumes.

 

i take what i can get and process as much as i can to dry in time for the winter season.

 

i do find with the demand so high the supply becomes more difficult and customers harder to please

Edited January 28, 2009 by firewoodman
schpellin

[Arob]

I remember seeing a book/handout that had approx water values for green wood. Ash was around 25-27% if i remember right etc. I know the rigging book has wet weights per cubic foot.

 

I'm not sure that's correct, 25-27% more likely represents the fibre saturation point, however I can't say what the average moisture content of green ash is. (It's very unusual to find green wood with m.c.'s below 40% - it can go up to 200% - this usually relates to the density, ash is pretty dense but there are many denser timbers, so we can assume that on average it'll typically be a good bit above 40%)

 

Above the level of fibre saturation point there is free (conductive) moisture within the cells, below that level the remaining moisture is bonded to the cellulose and so takes more energy to (break the weak hydrogen bonds and) dry, so you'll lose the vast majority of free water before the bonded water is lost.

 

Dropping below the fibre saturation point, with associated loss of bound water will affect dimensional stability and lead to 'movement' in the wood causing it to twist, split, etc.

 

Air drying alone is unlikely to bring the moisture content below 17%, (but as has been said in previous posts) this depends upon size, species, how split, etc etc

 

If you have the time, and wanted to check the accuracy of your moisture meter you could take a sample of the wood, weigh it, then oven dry it and weigh it again, a bit of a faff, but if you take a small enough piece (or increase surface area to volume ratio) it needn't take too long (but the smaller the piece the more accurate the scales you'll need).

[Dean Lofthouse]

Moisture content will not go below 17% when stacked under cover outdoors.

 

I have tried burning fresh ash and it's absolute crap in a stove compared to 18% moisture logs of any kind.

 

It's all about getting the most out of your log, I season till the moisture content is 18% and use very little wood to get a high output.

 

Anything above 25% is IMO inefficient and a waste of calorific value

 

I have a moisture meter so that I am not bullshiting the customer and guessing, if I say my logs are seasoned to 18%, I can guarantee they are and the customer will get maximum calorific value out of each and every log.

 

You burn poorly seasoned logs in a stove you have to have the air vent full open just to get it to burn right and go through loads of logs to get any heat out of it.

 

Burn 18% moisture logs which have been stacked at the side of the fire for a few hours and you have to turn the air intake right down to stop the stove glowing and by turning it down so the flames circulate instead of being drawn up the chimney, you can make a log last ages and still have the stove nearly melt.

 

Last lot I delivered had been ordered by someone who and got logs from someone else and they couldn't even light them, I tested them while there and they measured 45%, asked the customer to pick one of mine at random, split it and measured it and it read 18%

[Stephen Blair]

where did you get the metre dean, and how much mate

[Dean Lofthouse]

where did you get the metre dean, and how much mate

 

This is the one http://www.burntechshop.com/dual-scale-moisture-meter-p-129.html

[Stephen Blair]

This is the one http://www.burntechshop.com/dual-scale-moisture-meter-p-129.html

 

cheers dean, that looks the biz, i had only seen ones on ebay for 15-20quid, looked a bit cheap. thanks. hows that hedge doing, you might have to reply on the other thread.

[Dean Lofthouse]

Just completed hedge and been given the same amount to do in a couple of weeks time

 

This mondays job is.............................................yes..........a conifer reduction.