Uncooperative Wood

[Bryan Cramer]

This is a long story but I’ll try to make it short.

So so I was given some trees that were cut by a family member and because they were located in the Minneapolis area they were able to get a guy to cut the trees into boards. I told them to just slab cut the trees at about 2” thick. Most of it was an what we think is oak. As large as the trees were it’s probably a native species to that area of Minnesota.

https://sawmillcreek.org/blob:https://sawmillcreek.org/89d44c7b-3e90-459f-905a-725261d3f925

In exchange anger for the wood I’m making them a table. This wood has sat stacked for 2 1/2 years.

Being that the way the wood was cut I decided to make the top first and see how it worked first. A few splits or a slight warping won’t matter as it’s the top. I then would make a trestle base out of either more of the oak or metal. It’s 40” by 72”.

I brought the the wood into my shop and let it acclimate for 2 weeks before working it. Setting my meter to white oak wood denestity showed it was around 9% moisture.
https://sawmillcreek.org/blob:https://sawmillcreek.org/29245c6e-122d-464c-8714-e27ac71782b1


HereÂ’s the problem: there is an extreme amount of tension in the wood. It checks massively when I cut the ends off. This scrap was an off cut from the top and I four square milled.

https://sawmillcreek.org/blob:https://sawmillcreek.org/0da398b9-9c24-4643-9b62-72cf16903c2e

The the next day these checks developed.

https://sawmillcreek.org/blob:https://sawmillcreek.org/2e5a8eeb-e23a-46a1-83e0-9e0a26a60f4b

The he top has warped massively as well 3/8 over 40”. I took an even amount of wood off both faces for a total of 3/8”. 2” to 1 5/8”.
Some checks moved by a 1/4 overnight then stopped. Some of the wood split at the glue line as well.

https://sawmillcreek.org/blob:https://sawmillcreek.org/2ec57fb0-aa60-4a46-a8c9-e1589629a9b6

Anybody have any thoughts on why the wood has so much tension? All the off cuts when cutting go wild either pinching or opening up. Even cross grain cuts.
Ignoring the checks could I just force this top flat with a metal base? Obviously the bolt holes would be slotted allowing it to move just not up and down.

https://sawmillcreek.org/blob:https://sawmillcreek.org/ba0779a1-ff60-4dec-9dc8-cf0aa9a79ee7

I thought I wasn’t reading the wood moister right so I figured the density and it puts it in the exotic hardwood range. It is so dense a hammer rings on it like striking steel. With this setting the moisture shows 6%. Any suggestions? Will they even be a good epoxy river pour candidates?

[Bryan Cramer]

Apparently can’t post photos from my iPad. Will add some soon.

[Kevin Jenness]

The checking and splitting at glue lines makes me think the MC is not as low as your meter is leading you to believe. What sort of meter? If a pin meter, how deep into the wood are the pins reaching?

If the wood was stickered outside the overall MC was probably north of 12%. If so, two weeks inside is not going to lower the MC of 8/4 that much, especially with white oak, a slow drying species.

I would suggest doing an oven test on a section to establish the exact MC. In the meantime seal the cut ends thoroughly and expect to settle for a shorter, thinner table.

[Andrew Seemann]

In our area, wood like that can be difficult to work, since the center of 8/4 always seems like it has the moisture content of the previous season. By the time it acclimates to winter; it is spring. If the wood wasn't stickered it will be worse. Also, last summer and fall were so wet around here, it may have a higher MC than you would expect for something that had sat as long as it had. If it was outside, and you just brought it in 2 weeks ago, it may be still drying out.

That said, it almost sounds like you might some have tension in the wood, like the tree leaned to one side or some of the wood wasn't from the trunk.

I'll wait to guess the speeches until you post pics:)

[John K Jordan]

You can measure the absolute moisture content with the oven dry method, regardless of the species, density, or moisture content. It needs a small sample from the middle of a board, a oven such as a toaster over, a way to read temperature, and a sensitive scale. Far more accurate than a moisture meter.

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I wrote about the method here if you are interested. Ignore the messages where someone hijacked the thread with drying a bowl with microwaves.
https://sawmillcreek.org/showthread.php?263169-Moisture-content-by-oven-dry-method

JKJ

[Bryan Cramer]

What yall been waiting for....pictures. I'm back to my laptop as I was gone for work. I copied and pasted my first post with the pictures added and hopefully I made it a bit more clearer.

""""""""""So so I was given some trees that were cut by a family member and because they were located in the Minneapolis area they were able to get a guy to cut the trees into boards. I told them to just slab cut the trees at about 2” thick. Most of it was an what we think is oak. As large as the trees were it’s probably a native species to that area of Minnesota.
https://sawmillcreek.org/blob:https://sawmillcreek.org/89d44c7b-3e90-459f-905a-725261d3f925

In exchange for the wood I’m making them a table. This wood has sat stacked for 2 1/2 years.

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Being that the way the wood was cut I decided to make the top first and see how it worked first. A few splits or a slight warping won’t matter as it’s the top. I then would make a trestle base out of either more of the oak or metal. It’s 40” by 72”.

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I brought the the wood into my shop and let it acclimate for 2 weeks before working it. Setting my meter to white oak wood density showed it was around 9% moisture.
https://sawmillcreek.org/blob:https://sawmillcreek.org/29245c6e-122d-464c-8714-e27ac71782b1
Here’s the problem: there is an extreme amount of tension in the wood. It checks massively when I cut the ends off. This scrap was an off cut from the top and I four square milled.

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https://sawmillcreek.org/blob:https://sawmillcreek.org/0da398b9-9c24-4643-9b62-72cf16903c2e

The the next day these checks developed on the end grain.

https://sawmillcreek.org/blob:https://sawmillcreek.org/2e5a8eeb-e23a-46a1-83e0-9e0a26a60f4b
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The he top has warped massively as well 3/8 over 40”. I took an even amount of wood off both faces for a total of 3/8”. 2” to 1 5/8”.
Some checks moved by a 1/4 overnight then stopped after working it. Some of the wood split at the glue line as well.

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https://sawmillcreek.org/blob:https://sawmillcreek.org/2ec57fb0-aa60-4a46-a8c9-e1589629a9b6

Anybody have any thoughts on why the wood has so much tension? All the off cuts when cutting go wild either pinching or opening up. Even cross grain cuts.
Ignoring the checks could I just force this top flat with a metal base? Obviously the bolt holes would be slotted allowing it to move just not up and down.

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I thought I wasn’t reading the wood moister right so I figured the density and it puts it in the exotic hardwood range. It is so dense a hammer rings on it like striking steel. With this setting the moisture shows 6%. Any suggestions? Will they even be a good epoxy river pour candidates?""""""""""""""""""

To answer a few question my meter is a pinless mini-lingo D. It should reach 3/4" deep to hit close to the center. I followed their instructions to set it to an unknown wood and it ranks up with dense tropical hardwoods and got a consistent 6% reading. It doesn't machine easily or plane very well. It is very heavy too. I can get closer shots of the wood as well if anyone wants. Yes the wood was sticker 3/4" apart and stored in an unheated barn loft. out of the weather.

I honestly have never seen localish wood this hard and dense and heavy. Like I said you can make a hammer ring like striking a piece of steel. I also haven't had wood react to machining so quickly. Yes I have used some too wet wood and after milling it did warp a bit. Not splitting 1/4" at a time while moving then stopping. I marked the checks and splits that developed overnight on the top once I cut it to length and they consistently grew for a few days by 1/4" as the top warped then stopped.

I don't know how the trees were cut or if they were branches as I didn't see them standing or cut only a pile after it was milled. They'd have to be quite big as most pieces ranged form 15" to 28" wide. This was on a fairly steep hill so maybe that had something to do with it?

Thank yall for the help already. I van get more picture as needed.

[John K Jordan]

If you get end grain checks/cracks overnight this indicates the wood is not at EMC (equilibrium moisture content) for the current environment, i.e., too wet. If wood checks after bringing into a heated shop it may have been air dried or perhaps left in an conditioned space for a time after kiln drying and picked up a lot of moisture (making it is essentially air dried.) You can minimize end grain cracking when bringing wood indoors by first coating the end grain with a sealer such as anchorseal. If the wood is not quite dry it may take some time to acclimate to the heated space, even if properly stickered. It must not be tightly stacked.

Is your meter the pin type or pinless? A pin type will only read the mositure as deep as the pins are inserted. A pinless type (such as the Wagner I use) relies on you setting the proper density. They provide tables for density values of specific woods but be careful since wood density can vary a lot, even in the same tree. Also, if the wood is thin the reading can be affected by something behind it. Today I made the moisture reading on my meter change on a 1" Zebrawood board from 13% to 16% by placing my hand behind the board. Also, a pinless meter needs to be pressed firmly into a smooth, flat surface or it may read too low.

What I do for turning blanks is weigh and record the weight periodically (every few weeks or months). When the weight quits changing the wood is at EMC for my shop.

But if you really want to know the true water content, use the oven dry method mentioned earlier.

JKJ

[Kevin Jenness]

It does look like oak, and it acts like it is wetter than the equilibrium moisture content in your shop. If it grew on a sidehill that may have produced reaction wood. If it has been sitting flat on the bench as shown that may be contributing to uneven drying as well- can air get to both faces?

If it were me I would do an oven dry test a described by John Jordan to make sure of the moisture content before proceeding. As stout as it is I don't think you are going to force it flat, even if it has stopped changing shape. You may have to rip at the gluelines and reflatten once you are sure it is thoroughly dry.

[John K Jordan]

I just saw your question about the tension. Wood can develop a lot of stress if the tree was leaning or if the lumber was cut from a limb instead of a vertical trunk. Look up "reaction wood".

Reaction wood can bend and twist and warp when cutting. Can be dangerous without a splitter or riving knife in the table saw if it pinches the blade.

Wood can also twist as it dries if sawn from a straight log if it's sawn at an angle to to pith. This is due to the normal tangential vs radial shrinkage.


JKJ

[Richard Coers]

Did they saw branches? Branches are filled with stress and do not make good furniture. Bowls yes, but not furniture.

[Bradley Gray]

I think the oven test is a good idea to get the actual MC but no doubt the wood is still drying.

It is important to allow air to reach both sides. When I'm working on a big glue up like yours I keep the top sitting with stickers between the top and the surface underneath and keep it clamped flat. The concave top surface tells the tale that it is still drying.

What kind of ship is being built in the first pic?

[Bryan Cramer]

Thanks for the suggestions. It’s been about 4 going on 5 weeks that the wood is in my shop. I took the scrap and cut the checks of the end grain and they reappeared the next morning. Even the small cut offs move like crazy. It’s truly like cut a spring with the grain or cross grain sometimes it pinches or sometimes it splits apart but it always moves. I can’t cut an inch of without it moving in 2 directions. My meter is pin less and I did follow the instructions on how to set it to an unknown wood which is how I got my last reading. I will do the oven test on a piece that’s in the shop and one that’s in storage to confirm the moisture content.

I’m going to do some more reading on reaction wood. Thanks for that suggestion. It seems like that has something to do with it because some boards cup in the wrong direction I typically see according to the flat sawn grain rings.

That is not a ship just the hay loft of our barn that makes for great wood storage.

[Frank Pratt]

I've had boards that behaved like that and was never able to get any usable wood out of them. Time to cut your losses & toss it all into the firewood pile.

[Andrew Seemann]

It does look like white oak, and based on the end grain picture, very hard and dense white oak. It is likely that it hasn't fully air dried yet. The rule of thumb is a year per inch, but that wood is so dense and last year was so wet, that it might not even be half way dried yet. You might need to wait another year or two on the wood to finish drying, and even then, the center moisture will still likely be out of season.

White oak is difficult to dry. The old man had some white oaks from his property milled into boards --nice straight ones too. He stickered them up, painted the ends with the stuff, and tried to air dry them. He never got around to working them, so he gave them to me. I was able to salvage maybe 25% of it. The rest was too checked, warped, bowed, cupped, etc. For what he paid in milling vs what was usable, it would have been cheaper to buy kiln dried wood from the hardwood supplier. I ultimately ended up burning the rest for heat; it just wasn't usable as lumber.

Growing on a hill, if the trunk didn't grow straight but maybe leaned to get more sunlight, it could have significant reaction/tension wood in it. That won't go away, even with kiln drying. I recently used some kiln dried maple that was bought 40 years ago. One of the boards had reaction wood (even in commercial lumber, you occasionally find it). After 40 years, the wood still curled and pinched when I ripped it.

Edit- Frank just said what I didn't have the heart to; that there is a good chance you may end up burning a significant percent of that wood. It may just not be usable (what isn't usable will make outstanding firewood though). Best chance for usage is to let it dry for another year or two, bring it into the shop in fall, let it sit for a couple months, and hope for the best. Still, it may end up only being usable in small pieces.

[Prashun Patel]

You have a couple risks here.

Besides the moisture many mentioned (personally I don't think this is the issue; an attic and 2.5 years and the way you had it stickered, should have contributed to it being most of the way there) I suspect it's reaction wood. Most usable lumber for a tree comes below where the branches start. You appear to be north of that. In addition, slabbing causes either flatsawn pieces closer to the edge, or quartersawn pieces that go close to the pith. Pieces closer to the pith are prone to checking/cracking. The flatsawn pieces are prone to cupping. Coupled with built up tension that's released during planing or sawing, I can see where you get cupping and cracking.

Do you have pix of the pre-cut log?

[John TenEyck]

Looks like white oak to me, too. White oak doesn't play nice when it dries, especially plain sawn, and air drying makes it an even greater challenge to end up with good wood. It's very easy to get checks and stresses, especially if it was cut in the Summer and got exposed to direct sun and a stiff breeze during the first few days/weeks of drying. I ruined several hundred BF of white oak by letting that happen. From your account of the situation, I think you have a pile of firewood.

John

[Prashun Patel]

All this being said, I don't know that checking is a big deal. You may be able to re-flatten the top somewhat and keep it in decent shape with a well-designed base. Tops aren't structural, so as long as any warp can be gently kept in check and is not so noticeable to the eye (I used the does-a-pencil-roll-off-by-itself) test, then I don't think you or the client will really care long term...

I have and have made several slab/burl tops. Some movement or checking is not always out of sync with the aesthetic - especially when the primary motivation for the piece is posterity.

[Jacob Reverb]

I've heard of WO "case hardening" when drying. Don't know much about it, but that might be something to look into. I seem to recall hearing that it can be reversed. Google it, maybe.

[Frank Pratt]

I've heard of WO "case hardening" when drying. Don't know much about it, but that might be something to look into. I seem to recall hearing that it can be reversed. Google it, maybe.

My understanding is that case hardening happens when too much heat is used at the wrong times during kiln drying and this was air dried.

[Doug Dawson]

All this being said, I don't know that checking is a big deal. You may be able to re-flatten the top somewhat and keep it in decent shape with a well-designed base. Tops aren't structural, so as long as any warp can be gently kept in check and is not so noticeable to the eye (I used the does-a-pencil-roll-off-by-itself) test, then I don't think you or the client will really care long term...

I have and have made several slab/burl tops. Some movement or checking is not always out of sync with the aesthetic - especially when the primary motivation for the piece is posterity.

I agree. Although it's _nice_ for the wood to be flat and free from checks etc., it doesn't _have_ to be, you can always work around it. You are trying to convince the wood to be something that it is not.

[Jacob Reverb]

My understanding is that case hardening happens when too much heat is used at the wrong times during kiln drying and this was air dried.

From what I've read, it also happens (though less) with air drying. I think the main problems are the high degree of shrinkage from green to dry in WO, and the tyloses that run perpendicular to the main direction of shrinkage...sounds like a recipe for lots of internal stresses.

See:
https://www.finewoodworking.com/forum/white-oak#comment-275502

[John K Jordan]

...and the tyloses that run perpendicular to the main direction of shrinkage....


Tyloses are bubble-like structures within the pores of some wood, stopping or slowing water and moisture movement in the pores. They are present in woods like white oak and osage orange. You can see their "sparkle" with a microscope or 10x hand lens.

Compare the hollow pores in red oak to pores plugged with tyloses in white oak.

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[Jacob Reverb]

I guess I meant "medullary rays." I get them fouled up. Thanks.

[Scott T Smith]

Bryan, that IS white oak, and it appears to be stressed/reaction wood milled from either a leaning tree or limbs. In the photo showing the table top, it appears that one edge of the boards is significantly closer to the cathedral grain than the opposite edge. Unless you ripped several inches off of one edge of the board and little from the other side, this is an indicator of stress wood that is present in the lumber.

Plus, your description of the movement is classic stress wood description. There is nothing that you can do to resolve this. The wood never should have been milled to begin with.

the internal checking visible in the end grain usually results from the lumber being dried too quickly from green. Thick White oak is problematic in this regard.

Scott

[John K Jordan]

From Bryan's post:

It checks massively when I cut the ends off....
The the next day these checks developed on the end grain
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The end grain cracks formed parallel to the rays and perpendicular to the tangential direction. I've seen this 100 times on air-drying wood of various species. If I cut through a piece of incompletely dried wood and fail to seal the newly exposed faces the cracks will often develop overnight as Bryan reported, or in a few days. The report that the cracks formed after cutting some off the ends indicates to me there may still be a moisture gradient through the board. If more is cut off the end of the board the cracks can likely be cut away but will form again if there is still a moisture gradient through the board. Even air dried 2-1/2 years outdoors may not have been enough for white oak depending on local conditions. When I encounter end grain cracks I cut back the wood until they are gone then seal the end grain. Then wait.

It sure would be nice to know the actual moisture of a sample cut from the inside. And while at it, the actual moisture of a sample cut from the surface. Besides the oven method, checking various places on the end grain of a fresh cut with a pin-type moisture meter could show this. Another way to check for moisture in wood is to cut off a chunk away from the end of the board, weigh carefully, then reweigh over the next few weeks or months. If the weight decreases over time, it was not dry enough for the current environment. I use a scale that gives the weight in grams. I mostly dry woodturning blanks so I'm usually tracking the weight on dozens of representitive pieces.

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JKJ

[Tom Bender]

The first picture shows very few checks in the end grain, stored without sealing. My guess is that it was cut in winter when it was relatively dry to start with and then the drying was very gentle. Good for the wood but slow. Probably still a long way to go.

You have included a lot of 'active grain' in that top. Looks like knots and burl. It seems that this tree was low and wide with no clear trunk, or the good wood didn't come to you.