Moisture Content

[JohnnyNoName]

I finally got a moisture meter. It's a pinned meter from Garret Wade. I checked some of the wood in my shop, and it all came in at about 13%. SO I checked more of the wood in my shop, and almost all of it was about 13%. This worried me, because I thought it needed to get down to about 8% to be able to be worked. The wood that I tested as been in my shop for months, even years, so it has acclimated. As far as I know, I haven't had any expansion or contraction issues with my finished pieces. Should I be concerned?

Jonathan

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[Roger T]

Jonathan,

It just sounds like your material has reached its EMC. (Equalized Moisture Content) Modern kilns generally dry their stock to about 8% Mc. That is why it is advisable to let the wood sit for a while after you get it home to come to its EMC. As long as all your stock is the same, I would use it and have no fears.

Roger

[JohnnyNoName]

That's what I thought, but 13% seemed high to me. Thanks.

[Keggers]

In the "golden days" before central heat and air - moisture content wasn't as much of an issue. I see a possible problem when you bring your finished projects into your centrally heated and air conditioned home. If you could check the moisture content of some of the wood in your house you'd find that the moisture content was closer to 8% - at least it is in my home. That is the exact same moisture content of my lumber that I have in my shop - which also has central heat and air. The M.C. goes up a little in the summer and down a little in the winter.

Just some thoughts.

[Pete Bennett]

13% is about the best you're likely to get air dried. Here in South Western France I can just about get to that. But, more usually it's 15% I don't yet have the 'joys' of central heating and shall never have air conditioning so if I can get to 10% I shall be happy. It sounds as though your shop has an average 12 - 14% but, if you do have Air con you will need to find some way of getting that down to around 7-9%. If you have the room and the patience store the wood for your next home project in that room for as long as you can and it will, especially if you've already had it for some months or years, settle at the EMC of the house. To be honest a couple of percentage points either way once the timber is thoroughly dried will not cause it to move significantly unless you hit it suddenly with a big change one way or the other.

Chippendale and Co had it real easy when you come to think of it. A year per inch under cover but with plenty of air flow another few months in the room where it would eventually reside and they knew everything was going to be great.

[Dan S]

I finally got a moisture meter. It's a pinned meter from Garret Wade. I checked some of the wood in my shop, and it all came in at about 13%. SO I checked more of the wood in my shop, and almost all of it was about 13%. This worried me, because I thought it needed to get down to about 8% to be able to be worked.

Did you correct the reading for species and temerature?

[JohnnyNoName]

Did you correct the reading for species and temerature?

Dan -

I didn't, but I also checked multiple species (ash, maple, poplar, pine). All of them were the in the 13% range.

Jonathan

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[Dan S]

Dan -

I didn't, but I also checked multiple species (ash, maple, poplar, pine). All of them were the in the 13% range.

You should always do this, because the readings given by most of the lower end meters (< $200) assume your testing Douglas-Fir. You should always temerature correct as it will skew your readings as well.

For example take my meter if it says 12% and I specify the species is white oak, and then enter different temperatures, this is what it gives me .

30F: 13.3% - 14.3% (my meeter only gives ranges)

40F: 12.6% - 13.5%

50F: 11.9% - 12.8%

60F: 11.3% - 12.1%

70F: 10.7% - 11.5%

if I keep the temperature constant but very the species this is what I get (for this example i assume a meeter reading of 12% and a temperature of 60 degrees).

Teak 10.7% - 11.4%

American Elm 10.1% -10.8%

Hickory 11.2% -11.9%

Red Oak 11.8% - 12.8%

Poplar 13% - 14%

Cherry 13.2% - 14.2%

Eastern Red Cedar 13.9% - 14.9%

SYP 13.9% - 15%

[Rick LoDico]

13% seems high to me also but I've used 12% on a number of occasions without any problems. You should adjust for species though.