Moisture Meter Question

I picked up a General MMD4E moisture meter at Lowes the other day, and was curiously running around measuring the moisture content of various items around our home. I'm sure this meter isn't the most accurate, but it does give very repeatable results. Of course, this left me with more questions than anything.
I always heard wood should be dried to 8% to 10% for woodworking.
My meter shows 12% to 14% for lumber (various species) that has been stored indoors for over 10 years. In fact, I got that same reading from the cabinets I have in the garage, wood trim around the doors, and even from the sheetrock. How could I ever expect to reach 8-10 percent if everything is at 12% to 14%?
Out of curiosity, I measured some "green" 2x4's I picked up today for a remodel project and they came out around 14% to 16% on average too.
For that matter, measurements of my deck railings, and plywood siding came out around 14% to 16%.
My seasoned firewood averaged around 16%.
The only wood I got a higher reading with was my rotting wood chopping stump that registered around 30% moisture. :)
Admittedly, we have had a very wet spring here in the Pacific Northwest, so maybe 12% to 16% is just to be expected?
Curious.... :)
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On 7/1/2011 8:23 PM, HerHusband wrote:

In general, no significant dimensional changes will occur if wood is fabricated or installed at a moisture content corresponding to the average atmospheric conditions to which it will be exposed.
And basically that depends upon the part of the country you live in. In the far Pacific NW you are not too far off averages, most likely within the tolerances of the instrument itself.
<Also pay particular attention to the type of wood and the recommended calibration/offset for each type, which can really throw the reading off.>
Check out this chart.
http://www.fpl.fs.fed.us/documnts/fplrn/fplrn226.pdf
Also answers some more of your questions:
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr190/chapter_13.pdf
AAMOF, that whole series of government documents are a valuable resource.
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Bake some wood at 250 degrees. Boil the water out Then try your meter.
Interior humidity can be higher than that depending on the air conditioning and season.
Martin
On 7/1/2011 8:23 PM, HerHusband wrote:

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I buy quite a bit of hardwood from a SW Missouri hardwood mill and I trust the owner. On more that one occasion he has told me he keeps lumber in his kilns until it is in the 6% to 8% range. Then he racks it so it can "start soaking up humidity". A lot of his racks have wood in the 6% to 11% range. This is another reason why it is good to keep some project wood in your shop for a while so it can acclimate to your area. I am not comfortable with storing in my air conditioned basement and then moving it to a warm, humid shop. Might be wrong, but that's the way I work.
RonB
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On 7/3/2011 3:25 PM, RonB wrote:

Nothing wrong about that, in fact it's smart.
A very important proviso to wood movement which is often overlooked:
"In general, no significant dimensional changes will occur if wood is fabricated or installed at a moisture content corresponding to the average atmospheric conditions to which it will be exposed."
CITE: http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr190/chapter_13.pdf
IOW, within a roughly 2% swing in moisture content, there will be no significant movement at all.
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The only thing I think about is we live in SE Kansas within 70-80 miles of the Ozark dealer. In fact we are both pretty much in the Ozark weather pattern - wet!. When I store in my garage and build a project it ends up in and air conditioned home. I think about it but I have never had a problem.
About 10 years ago I built a couple of heavy tables (coffee and end)for our son and both had 8/4 Red Oak tops. The Coffee table has butcher block ends that are free to slide with expansion of the main table top. And slide it does! He also lives in the Ozarks and is air conditioned but also a tight a** Irishman. He runs his summer thermostat in the 78-80 degree range. We visit from time to time and I always check the table width with regard to the block ends. Since the Oak doesn't move much in grain length, there is usually a little variance in match. Sometimes the slab is a little proud of the end, sometimes, usually winter, it is even or vice verse.
Not earth shaking info, but kind of neat to watch wood movement in action. also the reason I attached top to frame with wood slide blocks.
RonB
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