Working with air-dried (AD) wood?

[John Miliunas]

The bulk of the wood I've used over the years has been kiln dried (KD), though I did pick some Cherry up about a year ago, which had been air dried. I may have an opportunity to pick up some more Cherry at a reasonable price, but it's also AD to about 12% MC.

So, the BIG question here is: What do I need to do to make this stuff useable for indoor projects?:confused: :cool:

[John Renzetti]

Hi John, About 12 yrs ago I had to cut down some PA cherry trees on my property to make room for the shop/greenhouse addition. I had the trees cut into some good logs and then brought a guy with a woodmizer in who cut the logs into various thicknesses etc. I stickered everything, sealed the ends and let it dry for about 3 yrs. The wood is all used up. I made a bunch of stuff with it, sold a lot and gave some to some friends who also made some nice things. The cherry was all at about 10-11%. What I found was one I got a moisture meter and did a bunch of readings on each piece, to make sure it was stabilized at around the 11% mark. Then I brought it into the shop and let it sit for a while. When it came time to surface, I would face joint first, then let the board sit to see if it would move and by how much. A couple of guys also told me they would surface one side and then bring the pieces into the house for a week or so. Then finish surfacing. I would also allow for a bit more movement than you would for stuff that is KD down to 6-7%.
All in all my experience and those of my friends that got some of this air dried wood also, was very good.
take care,
John

[Pete Lamberty]

I have no idea about how to prepare or use air dried wood. But if you brought two equally sized boards into your shop, (lets say that they are both similiar in density,species, etc.) one air dried and one kiln dried, wouldn't they have the same moisture content after some amount of time? How long that would be is not known to me. Would they have different working characteristics? Would there be other differences? Hmmmm..... :confused:

[Glenn Clabo]

John,
I've used air dried wood a lot. If you get it at 12% and store it correctly inside with good air (6-8%is best for nowaday houses) circulating it will equilize in anywhere from a few weeks to a couple of months. It all depends on what your storage air moisture is. If it's rough and you plan on rough planing make sure you plane the same from both sides.

I think air dried wood is better...especially if the kiln dryer tries to do it too fast.

[Chris DeHut]

Tell me where the stash is and I will check it out for you. It is most probably horrible wood that simply cannot be worked either by hand tools or power tools. ;)


In a more serious tone...

I have found Cherry to be good to work either way (air or kiln dried). Any species of wood will only get so dry, it's EMC (equalibrium moisture content). Air dried wood, in your area, takes about a year and a half to reach that point and it will not dry any further.

Whenever I pick up timber, I always check it's MC. If time allows, I let it sit around in the shop (Stickered) for a few months befor working it. I monitor it's MC against other timber in the shop and within my home. Once it gets acclimated (within a few percentages of what is in the home), I will use it.

A good way to keep track of what is good and what is not regarding timber that you purchase, is to keep track of the MC in the finished projects in your home. During the winter, it will be rather low, and during those wonderful HOT HUMID WI summers, it will be higher. This will give you a rough range as to what MC content you should try to purchase.

As I purchase most of my timber either in IL or in WI, I have seen that most of the purchased timber is around 2 - 3% higher than what I measure in my finished project at home.

In any case, when working on pojects, try to work with wood that is all of similar moisture content. Wild variations in MC between boards (can be common if not careful when purchasing), can create all kinds of nasty problem in furniture - during construction and worse, after completion and a year or so passes.

Hope this helps a little!

Chris








The bulk of the wood I've used over the years has been kiln dried (KD), though I did pick some Cherry up about a year ago, which had been air dried. I may have an opportunity to pick up some more Cherry at a reasonable price, but it's also AD to about 12% MC.

So, the BIG question here is: What do I need to do to make this stuff useable for indoor projects?:confused: :cool:

[John Miliunas]

Tell me where the stash is and I will check it out for you. It is most probably horrible wood that simply cannot be worked either by hand tools or power tools. ;)


In a more serious tone...


Whenever I pick up timber, I always check it's MC. If time allows, I let it sit around in the shop (Stickered) for a few months befor working it. I monitor it's MC against other timber in the shop and within my home. Once it gets acclimated (within a few percentages of what is in the home), I will use it.

A good way to keep track of what is good and what is not regarding timber that you purchase, is to keep track of the MC in the finished projects in your home. During the winter, it will be rather low, and during those wonderful HOT HUMID WI summers, it will be higher. This will give you a rough range as to what MC content you should try to purchase.


Hope this helps a little!

Chris
Chris, et all,
Thanks for all the great info. Now comes another question regarding the MC: What do you guys prefer for a meter? I mean, something which won't cost me a second or third mortgage!:) :cool:

PS: Chris, depending on how much there is, you might just decide to take a trip up and get some. I should find out this weekend!:cool:

[Glenn Clabo]

Here's a good thread John...Bob S has some good (as usual) info -

http://www.sawmillcreek.org/showthread.php?t=16260&highlight=Moisture+Meter

[James Boster]

I have used both with great success. I mill my own wood and kiln dry. When wood is kiln dried and then stored it will reabsorb moisture. The rate is dependant on several factors, mostly what the relative humidity is in the area it is stored. I have seen kiln dried oak regain 4% moisture in as little as a month. I said all of this to say that if you are buying kiln dried wood it may or may not be in the 6-8% range. If you store lumber for long periods of time before using it you need to control the humidity of the storage area. Cherry is the species you are asking about, cherry has little movement due to humidity changes. Oak and poplar on the other hand will move quite a bit with just 1-2% change in moisture content. My take would be if it's a good price buy it and aclimate in your shop then use.

[George Pell]

I have always heard that it's best to store the wood where it's going to be worked, but now it sounds like maybe it should be stored where the finished product will be kept? I make jewelry boxes and have always kept my lumber in my shop (garage) where it does go through the seasonal changes in humidity, but I have never had any problems with the integrity of the boxes after it goes inside the house. Have I just been lucky, or is stroing it in the garage okay? I guess I'm a little confused after reading this thread as to where it's best to store lumber. I work with both air-dryed and kiln-dryed lumber. I do from time to time have minor problems with warping, but I assumed that just goes with the territory. Thanks.

George

[Chris DeHut]

I have always heard that it's best to store the wood where it's going to be worked, but now it sounds like maybe it should be stored where the finished product will be kept? I make jewelry boxes and have always kept my lumber in my shop (garage) where it does go through the seasonal changes in humidity, but I have never had any problems with the integrity of the boxes after it goes inside the house. Have I just been lucky, or is stroing it in the garage okay? I guess I'm a little confused after reading this thread as to where it's best to store lumber. I work with both air-dryed and kiln-dryed lumber. I do from time to time have minor problems with warping, but I assumed that just goes with the territory. Thanks.

George
In a perfect world that would be the perfect situation. None of us (that I am aware of) can store our lumber in the house. So, the next best thing to do is to monitor the MC and use materials all with similar MC on a project. This way, as the MC levels out to what is indoors, the whole project shrinks or swells uniformly - thus avoiding many problems.

Warping and twisting is part of the game and I am pretty sure everyone has problems from time to time. I just had about 300 BF of Maple get real twisty on me after bringing it to the shop and storing it for about a month. Oddly, the MC from the time I purchased to the time I used it only changed on average 1% across the lot. But the twisting was pretty nasty, luckily, the material was destined for a lot of little pieces anyway.

Chris DeHut

[Martin Lutz]

Talk about twisting lumber, try bringing perfectly flat air dried lumber from humid East Texas to dry Colorado. I think I should start a propeller business:) . I've got some great 16" wide pine that the entire log has twisted at least 30 degrees one end to the other. Makes great kindling.


I use air dried lumber all the time. I try to design my projects to account for some additional wood movement with seasonal changes. I have found AD to be somewhat easier to work and it retains some beautiful colors that seem to get lost in kiln drying. This is esp. evident in Walnut. On the other side, some air dried lumber occasionally retains some internal stresses that proper kiln drying can help get rid of. It usually doesnt show up until you have picked the perfect board and tried to rip it on the TS. This is where a good knee high shut off is handy.

I use a Wagner pinless moisture meter. I really like it. I have compared it to some other pin type and they all read generally the same. I just dont like making holes in the wood. Make sure you can convert your reading to the appropriate wood species. I think most of them are calibrated around the density of Maple.

Hope this helps.

[Bob Smalser]

I have no idea about how to prepare or use air dried wood. But if you brought two equally sized boards into your shop, (lets say that they are both similiar in density,species, etc.) one air dried and one kiln dried, wouldn't they have the same moisture content after some amount of time? How long that would be is not known to me. Would they have different working characteristics? Would there be other differences? Hmmmm..... :confused:

They'd have the same M/C and maybe no other differences.

I say maybe because most commercial kiln schedules these days are a bit fast for my taste and can easily overcook boards on the edges of the stack.

Overcooked boards make fine furniture every day, but often don't have the nice color or resilience of airdried boards...and can't be steambent without a whole lot of breakage. You can really see it in walnut. The color differences between airdried and kilndried can be profound.

Bet there's a small endstack of boards behind most interior doors in my house in the process of going from the 12% they were in the outdoor stacks to the 9% I like to use them at. Even in boats I prefer 9% wood...it glues and takes finish quicker and more reliably and that tiny bit of expansion covers a minor sin or two in fit.

But in outdoor stuff you need to think of both seasonal extremes. It's real, real dry here from July to October and outdoor wood can go down to as low as 6%. Another reason I don't use 12% stock in boats even this time of the year. The shrinkage from 9 to 6% isn't cracked wood territory....but 12 to 6% certainly is.

http://pic3.picturetrail.com/VOL12/1104763/6583947/84760753.jpg

[Jim Becker]

Almost all the material I use, including cherry, is air dried. While a lower MC is better, what's most important is that the material throughout your project be the same MC, relatively speaking. That combined with design friendly to wood movement should make for a great result.

[George Pell]

Since I use small quantities of wood when I build my boxes, I could bring it inside my house prior to using it, but is there any real advantage to doing that? It sounds like the most important factors are design and using wood of equal MC?

[Martin Lutz]

George, The way I look at it is: I am slow enough with my projects that even if I did store my wood inside prior to construction they spend enough time in my shop during construction that the MC moves toward stabilization with the shop environment. Design your projects to move: 1) for wood movement within the project itself and 2) for movement across the country should your personal situation change or you sell it etc.


:) I have been known to store lumber inside though. When I was single in Texas I had one 12" X 14' bedroom stacked floor to ceiling, wall to wall, with my best lumber. I still hear about that from LOML whom I was dating at the time. That and the fact that I used the stove electrical circiut for my TS. I had a microwave, who needs a stove.:)

[Tom Saurer]

Why do people bring the wood into their house and then back into the garage to work it? Example:

Someone stores their wood in the house and then brings it out to be worked. They mill it down to size and start assemblying the furniture over a period of a week or two weeks, building a dresser or such.

Wouldn't the wood change moisture content during the two weeks, increasing the chance that the wood will move during the assembly time frame?

[Martin Lutz]

Tom, In my post above it was my only remaining area for "dry" storage. Besides, an extra bedroom was just wasted space. Now that I am married any lumber storage inside had better have a nice finish and have some functional or decorative use.:p

[Tom Saurer]

Didn't mean to infer you in anyway, Martin.

I've heard it from multiple people that the wood should be stored in the area that it will end up living. This didn't make sense to me because they would bring it out to their shop to work it and it would stay there for weeks getting aclimated to that relative humidity.

[George Pell]

Tom,
I'd also heard the same thing, but like you had questions about the wood becoming acclimated to the shop climate while it was being built.

One thing I do have questions about is say I have a piece of green lumber that will be air drying for the next year or so. Is there any benefit to drying it inside versus outside in the shop?

George

[Martin Lutz]

George, let the wood equalize somewhat outside before you bring it in. The lower humidity inside may result in some nasty internal stresses in the wood from drying to quickly. It could also result in cracking and warping . In E. TX I could dry to about 15% outside and about 10% inside. Colorado 10 - 12% outside, 6 -9% inside. Stack and Sticker it and try to keep it mostly dry and it will do fine. I liked drying wood in E Tx because of the higher humidity, the wood would dry slower and have less "complications". I think MO would be comparable.

[George Pell]

Martin,
Thanks for the information. Another question for you if you don't mind. I have two pieces of spalted maple that are about two inches thick, which have been air-drying for a little less than a year. I've kept them in my house the past couple of months, only because I need to clear a spot for them in my garage. There has been some cracking in one piece in a few places that are soft and punky, but otherwise they seem to be in good shape. From what you said earlier, I'd be better to store them in the garage as oppsed to inside the house? Would I be better off re-sawing them into 3/4 pieces now or waiting until they're dry. I know they'll dry quicker after being sawed, but I worry about them warping. Thanks again.

George

[Martin Lutz]

If the wood has not reached an equilibrium (outside surface vs. inside) then most likely if you resaw it the change in MC (one face vs the new resawn face) will cause warping. the wetter wood making up one side of the board will be the culprit. You may be able to control some of this but in my experience it is difficult. I have ruined more than one beautiful board because of my occasional impatience to resaw. The goal is to keep internal stresses to a minimum and preferably gone. One way to check is to cut a narrow slice from one end and then cut that into a tuning fork shape with the bandsaw. If the forks bend out or in then internal stresses are present. If they stay straight your piece is looking good. Refer to Bruce Hoadleys book "Understanding Wood". Its a great read if your interested. I believe he covers this area very well.


I hope this helps.