Buying old air dried boards

[john schnyderite]

I found wide 6/4 walnut boards that were air dried 10+ years ago. They were stored in a barn in PA in that time and moisture content is still 12-14%. A few questions:

1) How long will they take to dry to where they can be used if I store them in my garage or basement?
2) With boards that old, will there still be concern with checking or warping as they dry to usable range?
3) Any additional concerns with using walnut boards that are air dried, or 10+ yrs old?

[Dennis Ford]

1) The boards are at equilibrium with their environment and moisture content will not change unless their environment changes. It is possible that your garage and/or basement is no drier than where they are now.
2) If the boards warped and/or cracked when they dried from green to 12%, they will warp and crack a little more as they dry further. If they are reasonably flat now, I would expect them to still be reasonably flat when fully dry.
3) I would have no additional concerns above checking for quality as I would for boards of any age.

[John K Jordan]

That moisture is typical for air dried wood and will vary a bit from month to month but not change significantly.

My experience is walnut is pretty stable. I've brought plenty of air-dried into my conditioned shop with no detectable warping or checking. The time for further drying will depend on the temperature and humidity in your garage or basement. The boards should be stickered to allow air circulation through the stack.

One concern would be with power post beetles. Check the wood carefully for tiny holes and/or powdery frass. I've seen a lot of walnut with PPBs where the boards were stored in a barn or shed.

JKJ

[john schnyderite]

Thanks. Stupid question incoming. If air drying only gets boards to 12-14%. How do you get them down under 10% without a kiln?



That moisture is typical for air dried wood and will vary a bit from month to month but not change significantly.

My experience is walnut is pretty stable. I've brought plenty of air-dried into my conditioned shop with no detectable warping or checking. The time for further drying will depend on the temperature and humidity in your garage or basement. The boards should be stickered to allow air circulation through the stack.

One concern would be with power post beetles. Check the wood carefully for tiny holes and/or powdery frass. I've seen a lot of walnut with PPBs where the boards were stored in a barn or shed.

JKJ

[John K Jordan]

If air drying only gets boards to 12-14%. How do you get them down under 10% without a kiln?

Without a kiln you can move them into a heated/air conditioned space, stickered as mentioned. The moisture will decrease until they reach a new EMC (equilibrium moisture content). This may take weeks or months depending on the starting moisture, the thickness, the type of wood, and the conditions in the space.
The EMC depends on the relative humidity and the temperature in the space.
https://www.wagnermeters.com/moisture-meters/wood-info/what-is-equilibrium-moisture-content/

A good moisture meter helps estimate the MC but can be inaccurate. The most accurate method is a destructive test called the oven dry method.
I wrote this about that. (Ignore messages 3, 4, and 5 in the thread where readers somehow confused the moisture test with using a microwave to dry woodturnings.)
391176
https://sawmillcreek.org/showthread.php?263169-Moisture-content-by-oven-dry-method

JKJ

[Jack Sims]

Hey John, there are no stupid questions, that's how we learn. It's the stupid answers that will get you in trouble.:rolleyes: Wood forever remains hygroscopic in that it responds to it's environment and gains or loses bound water accordingly. My shop is air conditioned and heated with dehumidification that maintains 45% RH or lower. That keeps my wood supplies around 8% EMC (equilibrium moisture content). A few years ago I brought about 1,200 BF of Walnut into the shop that had only been cut about 2 weeks before. I stickered it (make sure your stickers are the same thickness so the wood dries flat) and put a small fan at the end of the stack and left it on low just to move some air and left it for a year. It turned out great with beautiful color (something you don't get with kiln dried and steamed Walnut). You should have no problem bringing your 12-14% wood down to 8% as long as you can maintain 45% RH in the room it is stored in. To get it lower than 8% you will of course have to lower your RH. I think 25% RH will yield 5-6% EMC.

Good luck!
D.O.G.

[Jack Sims]

A good book to have in you library was written by R. Bruce Hoadley and published by The Taunton Press in 1980: "Understanding Wood: A Craftsman's Guide to Wood Technology". It was revised and updated in 2000 and is available online at all the usual places. https://www.amazon.com/Understanding-Wood-Craftsmans-Guide-Technology/dp/1561583588

[john schnyderite]

Thanks all for responses. I would assume a basement would be easier to achieve appropriate humidity than the garage since it is better sealed and probably gets at least some AC/heat runoff from my ducts. I'm pretty sure my basement is normally over 60% RH, but I can run a dehumidifier and a fan over the stack. Do you think we're talking weeks or months with 6/4 walnut to lower the MC to usability.

Of note as well, what I'm making will end up in the basement when complete, so if it is generally humid there, is there less need to get my boards to a super low MC?



Hey John, there are no stupid questions, that's how we learn. It's the stupid answers that will get you in trouble.:rolleyes: Wood forever remains hygroscopic in that it responds to it's environment and gains or loses bound water accordingly. My shop is air conditioned and heated with dehumidification that maintains 45% RH or lower. That keeps my wood supplies around 8% EMC (equilibrium moisture content). A few years ago I brought about 1,200 BF of Walnut into the shop that had only been cut about 2 weeks before. I stickered it (make sure your stickers are the same thickness so the wood dries flat) and put a small fan at the end of the stack and left it on low just to move some air and left it for a year. It turned out great with beautiful color (something you don't get with kiln dried and steamed Walnut). You should have no problem bringing your 12-14% wood down to 8% as long as you can maintain 45% RH in the room it is stored in. To get it lower than 8% you will of course have to lower your RH. I think 25% RH will yield 5-6% EMC.

Good luck!
D.O.G.

[John K Jordan]

Of note as well, what I'm making will end up in the basement when complete, so if it is generally humid there, is there less need to get my boards to a super low MC?

That's the best case for something made of wood. After the wood reaches equilibrium, anything you make will not have to undergo the shrinkage and expansion that always happens when the object is moved to another environment. However, it will still react to seasonal changes.

JKJ

[Curt Harms]

Before we had a dehumidifier in our basement, I'd see 12% or a bit more in the summer and 6% in the winter. This is in humid S.E. Pennsylvania. Whether air dried or kiln dried, wood moves due to moisture. Some claim kiln dried wood moves less, I'm skeptical.

[john schnyderite]

John, if I store in basement, then bring up to garage for a few weeks to cut, assemble, finish, etc..won't that still screw with equilibrium when I bring it back to the basement for it's use? Any tips on that?

Also, should i still be shooting for 7 or 8% MC before I start working with it if it'll be used in an environment that has a little more humidity in the air, like a basement -- or can is it reasonable to let it acclimate to the basement and start working? How long should I give it, or should I still target a certain MC?



That's the best case for something made of wood. After the wood reaches equilibrium, anything you make will not have to undergo the shrinkage and expansion that always happens when the object is moved to another environment. However, it will still react to seasonal changes.

JKJ

[John K Jordan]

John, if I store in basement, then bring up to garage for a few weeks to cut, assemble, finish, etc..won't that still screw with equilibrium when I bring it back to the basement for it's use? Any tips on that?

Also, should i still be shooting for 7 or 8% MC before I start working with it if it'll be used in an environment that has a little more humidity in the air, like a basement -- or can is it reasonable to let it acclimate to the basement and start working? How long should I give it, or should I still target a certain MC?

I don't know. I have a sawmill and no kiln and know what works for me but I build very little furniture. Maybe for you the first thing will be to let the wood reach a new EMC in the basement - shouldn't take long since it is already air dried. Then measure and adjust the relative humidity and temperature in the garage if it is significantly different from the basement. Perhaps you will find that the conditions are close at the time you are ready to work.

Woodworkers deal with wood movement all the time, often working in unconditioned spaces and building for conditioned spaces. It's important to pay attention to the possible wood movement anyway since what you build for the basement may end up in another space later. Furniture makers design joints and such to allow for movement. I do very little of that, mostly concentrating on woodturning. There are many experienced people who read these forums, though. You might search the general and design forums or ask specific questions like this in a new thread so more people will see it. Make sure to use a thread title that will catch the attention of the right people!

I didn't see where you said what you plan to build with this wood. If you ask further about wood movement in a new thread perhaps you could provide some specific detail.
Also, you might first consider the numbers and how the expected movement would apply to your designs:
https://www.popularwoodworking.com/tricks/how-to-calculate-wood-shrinkage-and-expansion

JKJ

[Art Mann]

Everyone who is worried about air dried lumber should take a pilgrimage to Williamsburg and look at the exquisite 17th century furniture that is on display. Absolutely none of it was kiln dried. What is more, their houses were not climate controlled. Moisture content is important but it isn't quite the serious problem that some woodworkers think.

[Tom Bender]

I agree with Art, don't overthink this. Do accommodate some movement in your construction, as you should with any wood.

Let's back up to is this wood worth hauling home?

1. Definitely don't import bugs into your home. They have probably moved on by now but may have damaged the wood.

2. Inspect for end checking this can reduce the useful length.

3. Check for rot, wane, sapwood, wavy grain etc.

4. Check for surface checking. This can make it all firewood.

[John K Jordan]

Everyone who is worried about air dried lumber should take a pilgrimage to Williamsburg and look at the exquisite 17th century furniture that is on display. Absolutely none of it was kiln dried. What is more, their houses were not climate controlled. Moisture content is important but it isn't quite the serious problem that some woodworkers think.

Art, I agree. But what I've seen in a lot of earlier furniture was attention to letting the wood move with the seasons rather than self destruct. In contrast I recently saw a very nice custom dining table at a friend's house, built by a friend of theirs who didn't know to allow for movement. The table was coming apart in less than two years.

JKJ

[john schnyderite]

I will definitely check the boards over. I can see there is little to no checking on the ends and boards seem to be stacked well -- owner claims they are straight and mostly clear. I will look for signs of bugs. These are 20" wide boards and none are live edge, so I don't envision there being much sapwood. Not sure if I'll be able to get much an idea on grain figure with old rough boards like this, but if they are bug free I'm pretty sure I'll take them. At under $5 per bd ft, its less than half what my lumber yard charges so I should come out ahead even if there's some waste.


John, any good resources for building with allowances for movement? I'd like to learn more.



I agree with Art, don't overthink this. Do accommodate some movement in your construction, as you should with any wood.

Let's back up to is this wood worth hauling home?

1. Definitely don't import bugs into your home. They have probably moved on by now but may have damaged the wood.

2. Inspect for end checking this can reduce the useful length.

3. Check for rot, wane, sapwood, wavy grain etc.

4. Check for surface checking. This can make it all firewood.

[John K Jordan]

...any good resources for building with allowances for movement? I'd like to learn more.

Any good book on making furniture will have good information, as will some magazines. I've seen threads on this and other forums discussing this. Search this forum with the box above or search Google for wider results. I'm guessing there are youtube videos too but I've never looked.

R. Bruce Hoadley's book "Understanding Wood" is highly recommended as a place to start. https://www.amazon.com/Understanding-Wood-Craftsmans-Guide-Technology-ebook/dp/B004WYO862 I have a spare copy just to loan to friends so I always have one copy handy.

To cover all humidity conditions, you have to first consider the what you will be building. Read Hoadley's book or others to understand how wood moves, most expansion/contraction is tangent to the rings, usually about 1/2 as much radially (the basis for the T/R ratio), and almost nothing along the grain. The wood species itself is a factor as is how it is sawn. Quartersawn boards behave differently from flat/plain sawn boards. The type and method of finishing can play a part. Small, narrower things need different consideration than wide boards and glued up panels. Cutting boards, signs, checkerboards, and drawer fronts - usually no problem. Wide tables need to allow for expansion/contraction relative to the supporting structure underneath, sometimes made with connections like slots that that allow sliding. In raised panel doors it is easy to provide space for movement.

I'm definitely not the best person to ask and this sub-forum on Sawmills and Drying might not be the best place, but you could probably find expert advice with a new thread as mentioned here:
https://sawmillcreek.org/showthread.php?266930-Buying-old-air-dried-boards&p=2838091#post2838091

But as someone mentioned, don't fret too much. Learn the basic whys and hows enough to avoid a huge blunder. I only build furniture and cabinets for my own use, but even with my limited knowledge I can say that everything I've built so far is still in good shape, some even after nearly 50 years, for example one bathroom cabinet with raised panel doors that is subject to severe humidity cycling.

JKJ