To some of the more learned members of this forum.

[chilli]

My understanding of 'moisture content' follows Quickthorns 'dry' basis. Therefore, if say, a lump of fresh cut willow has a moisture content of 120%, then the weight of water is 1.2 X the weight of the wood in the completely dry piece.

If air drying reduces the moisture content to 20% then the piece will weigh just 54.5% of it's original weight.

[davetaz]

:001_smile:Brilliant thread, haven't laughed as much in ages, cheers everyone

[davetaz]

I reckon you got it right earlier, if a lump of wood is 32% water then 68% isn't water (ie pure wood) therefore 68% x 8kg = 5.44kg is pure dry wood. To find out its weight witha mc of 11%, multiply 5.44kg by 111%, = 6.038kg

[Dean Lofthouse]

No thats wrong again.

 

It's easier to think of it as weight. so

 

If the original dry log weighs 1000 grams

 

The you add 32% moisture

 

that makes the log 1320g

 

But that doesn't mean 68% is the log,

 

because 68% of 1320 is 897g

 

whereas 68% of the dry log is 680g

 

I can't even think straight now, someone sort it out

[Catweazle]

I reckon you got it right earlier, if a lump of wood is 32% water then 68% isn't water (ie pure wood) therefore 68% x 8kg = 5.44kg is pure dry wood. To find out its weight witha mc of 11%, multiply 5.44kg by 111%, = 6.038kg

 

That doesn't work because the 11% is of the weight of the dry wood rather than being 11% of the wood-including-water.

 

No thats wrong again.

 

It's easier to think of it as weight. so

 

If the original dry log weighs 1000 grams

 

The you add 32% moisture

 

that makes the log 1320g

 

But that doesn't mean 68% is the log,

 

because 68% of 1320 is 897g

 

whereas 68% of the dry log is 680g

 

I can't even think straight now, someone sort it out

 

If you want to get the weight where the water is 32% of the wood-including-water weight you have to calculate a multiplier - in this case 100/(100-32) = 100/68 = 1.47 .

 

So take your 1000g dry log and multiply it by 1.47 = 1470g when it has 32% ( by weight ) water. Double check by doing 68% of 1470 = 1000 .

 

 

 

If you want to calculate by the other method, for example when the log is described as having 32% water but it is not by weight but in relation to the wood weight (so you could have say 140% for example) then the calculation is;

 

Wet Weight = Dry Weight + (0.32 x Dry Weight)

 

Wet Weight = Dry Weight x 1.32

 

Wet Weight = 1000g x 1.32 = 1320g

 

 

Converting from a wet weight with 32% to 11% using the " not % by weight" (NBW) method;

 

Wet weight =1320g ( at 32% NBW )

 

Dry weight = Wet Weight / ( 1 + 0.32 ) = 1000g *32% converted to 0.32 for clarity.

 

Add 11% (NBW);

 

Wet Weight at 11% = 1000g x 1.11 = 1110g .

 

 

To try this with a 150% ( NBW) water content, ie more water than wood;

 

(Assume dry weight is 1000g as above, water weight will be 1500g)

 

Wet Weight at 150% = 2500g

 

Dry Weight = Wet Weight / ( 1 + 1.5) *150% converted to 1.5 for clarity, it would be 150 / 100 but I can't do the graphics.

 

Dry Weight = 2500 / 2.5 = 1000g.

 

 

So for the original equation with 8000g at 32% (NBW) to 11% (NBW);

 

Dry Weight = 8000g / (1 + 0.32)

 

Dry Weight = 6060g

 

Add 11% = 6060 x 1.11 = 6727g

 

 

 

Probably

[penfold]

:alberteinstein:

[bob]

just goes to show there are no learned members on this forum

 

P.S Who cares sell em by volume:thumbup: