Moisture content

[Russell Stanton]

I have several Big Leaf Maple platter blanks i.e abt 10" sq and 2" tk. They have been sitting for several years with wax on them. I just checked moisture content and got readings of around 11.5 to 12 % .
As a further test I checked some KD maple and got reading around 8 -8.2%. My question is would the platter blanks be dry enough to finish turn to a platter or should I rough them and then let them dry some more?

[Joe Meirhaeghe]

I'd prefer to have wood 10% or less. However I usually figure anything at 12% or less is good to go for turnings & it hasn't caused me any problems so far

[David Walser]

A lot depends on the average humidity in your shop. In my area, 11% moisture is considered wet. But, I live in Arizona. We invented "dry". In Utah, the furniture mill I worked at wouldn't cut wood until the moisture content was below 10%. We didn't finish parts and install them until the moisture content was 6% or less. In your case, since the kiln dried maple is at 8%, I would say your platter blanks are not dry. I'd scrape some of the wax off of them and let them dry some more. Or, as you suggest, rough turn them.

[James B Lee]

Here in Pittsburgh my wood is dry at 11 to12%. My workbench and everything that's made from wood in my shop is between 11 and 12%.
Check the wood in your shop that you know to be dry. Salem SC may be a little different from Pa.

[Scott Hackler]

Also keep in mind that the usual moisture meters are only reading moisture to the depth of the probes and in all likelihood the inside of a blank is not as dry as the outer portions. For your results I would say no they are not dry enough to turn to final thickness if you want to prevent warping.

[John Keeton]

If you have a bandsaw, cut the blanks into rounds and check the moisture content with your meter at the deepest point of the removed corner. That should be a better indication. In my area, I would turn at 10-11%. It can be difficult to air dry wood to 6-8% because of ambient conditions. In your area, I would think 6% wood would actually gain moisture as it stabilizes and acclimates to your shop conditions.

[Reed Gray]

Most air dried lumber, especially if it is dried outside, is in the 10 to 15% MC. Take it inside the shop for a year or so, and it will usually go below 10%. Out of the kiln, it is 6 to 8%, which is ideal for furniture. So, 8/4 lumber (8 quarters thick, or 2 inches) will reach equilibrium with about 2 years of outside drying. Your piece will be 'mostly' dry, which means you could turn it, sand and finish with no major wood movement or moisture issues. It may, well probably will move a bit after turning. Wood always moves.

robo hippy

[Russell Stanton]

Thanks for all the advice, I won't be turning them for another month or so and will probably mount one and turn to final and see what it does, will report back, if I can remember to do so.

[Stan Smith]

Also keep in mind that the usual moisture meters are only reading moisture to the depth of the probes and in all likelihood the inside of a blank is not as dry as the outer portions. For your results I would say no they are not dry enough to turn to final thickness if you want to prevent warping.

I had been wondering the same thing. I just checked my roughed walnut bowl and got readings at various points from 11-20%. I checked all four sides. Of course the inside was the wettest . The weather here is very hot and dry. thanks for your comment.

[Aaron Craven]

Russell, I also live in SC, and after two years, I would have thought it would be dry at 2" thick. But in comparison to the KD wood, it does indeed sound like it's still not quite dry. Perhaps the wax has slowed it down. At 12% though, I would expect it to be fairly stable (it will probably still warp, but not enough to tear itself apart). You can probably safely speed the drying process up by getting the wax off the piece. Roughing will speed it up more (less wood for the moisture to migrate through). For me, 8-10% is about what I shoot for in the finished product. I dry my wood in a barn where the temperatures get pretty high in the summer. The wood in there will sometimes get down to 5-6%, but it regains that moisture once it's out of the heat. SC seems to have periods of both high and low moisture (this summer has seemed particularly wet where I'm at), so all these numbers are pretty variable for me.

Of course, a little warp can be very nice sometimes, so I'd consider turning to final thickness and seeing what the wood gives me as well.

[Stan Smith]

There sure is a huge variance in moisture depending upon where you live and weather patterns. The weather seems topsy-turvey to me all over our country. I live at the end of the Sacramento valley surrounded by mountains. We have heat inversions. The only wood I have outside is junk wood that I don't want or need, Someone will eventually take it for kindling. I've bought wood from NC Wood in NC and it usually has a moisture content of over 30%. I have had to scrape part of the parafin off to get it to dry faster.

[Jeffrey J Smith]

I live very near the extreme upper left hand corner of the Pacific Northwest on an island that's about 5 miles, at most, from the International border. My shop is less than 200 feet from the water's edge - good old Puget Sound. If I buy KD wood for furniture, I take it home and let it stabilize (it will usually take on moisture) to adjust to ambient conditions. Even in today's relatively high, dry heat (at least for us), the driest I usually get on wood that's been in the shop for a while is 10%. 12% is more usual. I seldom use the moisture meter any more, just let it set for a while until it feels right.

[daryl moses]

I seldom turn anything less than 12% MC. At around 12% it's going to be stable enough for bowl turning.
A bowl turned to a wall thickness of 1/4-3/8 at 12-14% will dry very quickly sometimes while still on the lathe, and usually "warps" very little in my experience. In fact most bowls 10-12 inches in diameter at those parameters will usually only warp less than 1/4 inch.

[Jamie Straw]

Like Jeffrey, I'm on Puget Sound, though south nearer to Seattle. Rarely does the wood in my shop get below 12%. Since you have several blanks, why not finish-turn one and just see how it goes? You'll know in a day or two, methinks.:)

[Michael Mills]

I'm outside of Charlotte and anything <14% I consider dry enough to finish turn.
If outside it will reach equilibrium and that is as dry as it will get. Scanning the cites listed for SC your point should range between 11.6 and 14.6 depending on the season and your location. Here is a chart (about page six) for cities and their equilibrium.
http://www.fpl.fs.fed.us/documnts/fplrn/fplrn268.pdf
Prior to finish turning I occasionally bring it inside the house for a few weeks to let it adjust more to final conditions.

[Stan Smith]

I'm outside of Charlotte and anything <14% I consider dry enough to finish turn.
If outside it will reach equilibrium and that is as dry as it will get. Scanning the cites listed for SC your point should range between 11.6 and 14.6 depending on the season and your location. Here is a chart (about page six) for cities and their equilibrium.
http://www.fpl.fs.fed.us/documnts/fplrn/fplrn268.pdf
Prior to finish turning I occasionally bring it inside the house for a few weeks to let it adjust more to final conditions.

Hi Michael. Many thanks for including that chart. I didn't even know that one existed. It's very interested. Our town, Redding,CA, is on it, too. The chart and narrative are very comprehensive. thanks for sharing.

[William C Rogers]

I'm outside of Charlotte and anything <14% I consider dry enough to finish turn.
If outside it will reach equilibrium and that is as dry as it will get. Scanning the cites listed for SC your point should range between 11.6 and 14.6 depending on the season and your location. Here is a chart (about page six) for cities and their equilibrium.
http://www.fpl.fs.fed.us/documnts/fplrn/fplrn268.pdf
Prior to finish turning I occasionally bring it inside the house for a few weeks to let it adjust more to final conditions.


Second the thanks, even Evansville IN is in there.