# Wood density questions

Ok, so I've seen lately some requests for help identifying wood and the request to measure density comes up. So I imagine one is supposed to measure accurately the volume of the wood and the weight to find density.
Questions
1) Doesn't the moisture content of the wood have to be taken into account? Won't a sample with a mc of 20% be heavier than a sample with a mc of 10%. I havn't seen reference to measuring the mc of the wood.
2) What is the standard unit of measure? lb/cubic in?
Frank
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Yes. Most tables of wood density include the moisture content used in the measure. If you can measure your wood's mc, then adjust accordingly. If not, you can at least give yourself some error bound.

Specific gravity seems to be common. Calculate the density of the wood and divide by the density of water.
I think that the density measure is not an extremely valuable measure, but it can make the difference if you know little about the wood in question. For example, I found some luaun that the dealer said was quite light but didn't know the exact species. I measured and weighed it and found (on the web) that there was only one really light species and it was a similar colour to one heavier species. How to tell them apart? The density told me it was the heavier one and the dealer was less than, ummm..., correct.
The engineer in me says I'd rather have more info than less.
Mike
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Wood moisture content is usually measured as percentage of dry weight. It is therefore possible, with green wood, to have the reported moisture content exceed 100%. For this reason, green wood moisture content is usually expressed as percent of present weight.
wrote:

account?
the
colour
was
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No "eureka" here. Specific gravity is easy to compute by the submersion method.
http://www.fpl.fs.fed.us/TMU/publications.htm Properties of wood well explained.
wrote:

account?
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+ + + It is terribly complicated, at least in the US. you can measure the volume of the wood (green) you can measure the volume of the wood (ovendry) you can measure the weight of the wood (ovendry) and start calculating. Perhaps with enough imagination you can actually use the resulting figure
Over here we take wood at 12% or 15% and weigh it. This is expressed per cubic meter or cm. Then we know what we have. No imagination required. PvR
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Over here, we take wood at 12% or 15% and put it back in the kiln until it's dry.
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it's dry.
+ + + Sometimes that happens here too. Then we will sue. They are supposed to take it out of the kiln at 12 or 15%. PvR
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PVR notes:

Really? Makes it hard as hell to get that 6 to 8% you need for furniture and cabinet work, doesn't it?
Charlie Self "Ain't no man can avoid being born average, but there ain't no man got to be common." Satchel Paige
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Not if you're living in Holland. Something about that sea air. Also, IIRC, and it was some time back, central heating is not common.

until
and
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+ + + Well, we are in the Netherlands (with Holland being some tens of kilometers away, and today central heating is pretty common (personally I don't have it, but I am an exception).
The OP didn't specify what purpose the wood is to be put to. If I take a standard table of wood densities this gives the data mostly at somewhere between 12-15%, as this will be what is used for more purposes. The actually desired humidity of wood can be a little higher or lower depending on where the final product is to be put, but 6-8% is not on the books. Some woodtraders do have problems with kilns in Germany which do dry to 8% and "forget" to take out "our" wood at 12%. Some do sue.
A fair amount of imported wood is dried here to its final moisture content. The real problems occur in construction when the builders put supplied wooden doors, doorframes, etc outside in the rain for a few weeks before putting them in. PvR
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