What is best moisture content of wood

[nshalsk]

I just got some 2" planks of walnut that I am looking to convert into a table so will have to glue up several boards. They are currently about 8 feet long and have perhaps 2" of cracks at either end. Boards were stored outside, but in a shed at sawmill - but not sure how long they were aged after cutting and my acquiring. The end cracks don't seem to be increasing in length since I've gotten the boards but they are stacked in an outside garage with high humidity levels. Before I commit to cutting the boards to length any input on how long I should wait.

Thinking also of moving the boards inside to a lower humidity for a month or so to see if this changes the drying process/

[MikeG]

6%-8% is pretty normal for hardwood.

[dpb]

Air-dried won't get below about 15-20% and will have undoubtedly reacquired some if was below that if has been in a humid location.

Around 10% or lower is desirable for stability for inside use.

"Rule of thumb" is about 1-yr in dry location/inch of thickness to reach equilibrium w/ outdoor levels.

Ideal would be to arrange a solar-kiln to dry this some more, otherwise unless you have quite some time to wait and a really dry location to store it, you're likely to experience grief when it is sawed/planed and fresh surface is exposed.

More trouble can be expected in drier locales and colder areas where winter heating causes really, really low RH's, less (but not zero) in more humid, temperate areas.

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[else24]

I'm not trying to be flip, but I've put my ligno on lots of air-dried wood and gotten readings of 10 percent and under. Is the meter that far off? Checks on green wood and kiln-dried are always in the range I'd expect, except it redlines at 20%.

[dpb]

How old and what species and are you sure you got a reading representative of the innermost section(s) of the material?

_Eventually_ in an indoor environment w/ climate control it will dry. I was speaking (although I didn't specifically condition it) of relatively new-sawn material that had only been outside...

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[George]

You are correct, and your meter probably is close as well. Wood is "best" at the EMC (equilibrium moisture content) of the place where it will reside as a finished piece. Different in San Francisco than Phoenix, that's for sure.

Woodturners weigh their stuff to ascertain if it has equalized with the Relative Humidity of the air around it, and if you're curious, you can use a meter or a humidity gage to determine numbers. Which don't mean a lot in terms of stability, since the wood will gain or loose moisture and change dimension along with changes in relative humidity.

Free good stuff at

for the download. Chapter three will tell you how wood dries.

[spaco]

My air dried wood stabilizes at about 16% moisture in western Wisconsin. I just got a new Ligno ??? ($198) and tested a lot of stuff; walnut, basswood, white oak, cherry, black ash, elm, etc. and it was all pretty much the same when I read it in March. Some if it (it's all stickered) has been out there since 1978, the most recent was put there about 5 years ago after the saw got done with it and it sat outside, under cover, stickered for a year.(There's about 10,000 bd ft of it out there and mabye we will finally get to some of it). A friend who lives close by, and is very conscientious about getting to the 6-8% range has installed 18 inch wide shelf brackets all the way around the top of his heated shop, about 2 feet down from the 10 foot ceiling. On these shelves he stacks the air dried wood that is next to be used, for a month to 6 weeks before making furniture. Says that does a great job of getting to his 6-8%.

Pete Stanaitis

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snipped-for-privacy@earthl> I just got some 2" planks of walnut that I am looking to convert into a

[Andy Dingley]

No, this is a misunderstanding. It dries after a month or two, even when relatively fresh. Why it stops moving after some years is because it stops _moving_, not that it stops changing its moisture content.

As to "You can't air dry below 15%" then that's just wrong. If it were true, then we wouldn't have a problem of complete pieces made of 15% MC timber drying out even further after compeltion and then cracking!

Read Hoadley or the on-line copy of the Forest Products handbook.