# Straighten a short, slightly warped board?



## dglevy (Feb 3, 2012)

Hi all,

I've gotten two beautiful redwood boards to make into cutting boards*. The boards are 1" x 12" x 15" each -- quite short. But they both have a slight twist in them. It's not a big deal, just 3 mm height on a corner on one, and about 5 mm on the other. But I'd like to straighten them, if possible, before I apply mineral oil.

I do not have access to woodworking equipment; I live in a small apartment in downtown DC. I talked once with a guy who salvages wood from old farmhouses and barns and he happened to mention that one can leave boards in snow for a day (this was in Vermont), then let them dry, and they can warp in a different direction--hopefully in the right one... Does anyone have any experience with this method and can explain how one does it?

Thanks in advance for thoughtful and informed comments.

David

*I don't mind the fact that redwood is soft; in fact, I want it to be soft to save the edge of my precious japanese kitchen knives.


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## RenoStruct (Feb 3, 2012)

I see you are ok with the soft quality of the wood, but the redwood is only about half as hard as you need for a cutting surface. You want a wood around or above 1000 on the janka hardness scale for cutting boards and counters, redwood falls between 400-500. As much as it's a sanitary issue (and all the little micro-cuts are a huge issue), it's also an issue of getting a good chop. You'll tend to pinch your herbs and make incomplete cuts through skinned items when the wood gives.

Teak is awesome, maple is very commonly used, walnut. Tight-grained hardwoods are what you need.

Maybe what you have there is a future cheese tray? If you have no tools other than a screwdriver, you could screw in some tiny screws at each corner from underneath, adjust them so that the tray sits flat on all four corners, rub with oil, then use some wire shelving caps to finish off the screws:

http://www.homedepot.com/h_d1/N-5yc...ngId=-1&keyword=wire shelf caps&storeId=10051

Not sure that's going to flatten out. I'd say either roll with it, or move on. But that's just an opinion--someone else has the best answer out there. It will be hard cutting on a warped board.

Good luck (go for the cheese tray, buy a cutting good cutting board for your knives)

RenoStruct


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## BernieL (Oct 28, 2011)

Although I've never tried it myself (I have a well equipped workshop), old timers used to straighten their warped table tops by wetting down a flat grassy area on a warm sunny day, place their warped table top on the ground and place heavy objects on the high points. Moister is very problematic in woodworking, but it can also solve problems. When I make furniture, the very last thing I always do, after sanding, is I take a damp cloth and wet down all surfaces. This process is called whisking because it literally raises all the loose fibers left in the wood and pops them out to give me a hairy surface which I hand sand down with a fine 180 grit paper. Another thing the wetting down does, it pops up any dents I might have put in while working the wood. 

We live in an old farm house and I love the wood floors (hard and soft). The smaller rooms have wide pine boards which had quite a few deep dents over the years. After sanding down my floors, I dealt with the deep dents by wetting them down and placing a wet cloth over them. I then used a hot iron (cloth iron) and steamed out the dents. 

A possible solution for you might be to soak your wood, place them on a cookie sheet with a heavy object on them, and place this set up in your oven set at 325???

Once you have dealt with the warping, your problem may not be solved. You need to protect your work from future warping. If your cutting board is to be placed in a permanent set up, you need to glue it into place while it is flattened. If you plan on making a free board, you need to pay attention to the grain of your wood before gluing them up. Look at the ends of your boards and notice the growth rings. Make sure you glue your boards in opposite pattern directions. You need to end up with the end grains displaying alternate "U" and "n" pattern. 

Chances are that you will still end up with a few minor bumps along the edges after the glue up. If you are very careful, these bumps will be minor but they can be corrected with a simple cabinet scraper found at a woodworking store like Rockler or Woodcraft. This > $10 tool should solve your problem. If you have more serious bumps, these cabinet scrapers may still be the final solution, but you may also need a hand plane. I hope this info helps you. Find a woodworker in your area and even a friend of a friend may like to help you for free.


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## dglevy (Feb 3, 2012)

thanks for your replies! 

using screws and shelving caps is an excellent suggestion and i will do that if worse comes to worse. i am going to use these boards for cutting, for sure, so i don't want to get sidetracked by the question of soft vs hard wood for cutting boards.*

the story about the old-timers soaking their table tops is a fascinating one. *that's what i'm talking about! if only i could find an old-timer...*

_A possible solution for you might be to soak your wood, place them on a cookie sheet with a heavy object on them, and place this set up in your oven set at 325???_

that would be marvelous, if it worked. but couldn't that just as easily make the boards warp even more?

gluing them together after getting the warps out is certainly a solution but, frankly, i don't want to deal with glue and clamps and all that, and then end up with a board that is double the thickness and double the weight. i just want a simple, feather-light, one-ply board and, as i said, if worse comes to worse, i will just put a screw in one corner and leave it at that.

thanks again for your comments. at the moment, i'm hoping an old-timer somehow is on the internet and will see this thread--a long shot, i know. but, once i have the general principles in hand, i can start to experiment with straightening boards. this is going to be a life-long hobby, i suspect...

*here is the long (62 comment) discussion i initiated on a kitchen knife forum about cutting boards. i have already made and gave away two fine cutting boards for a staggering total cost of $12, one of poplar, the other of quarter-sawn sycamore, and greatly enjoyed the process.


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## MNsawyergp (Jan 31, 2012)

You used the term "twist", that is completely diffferent to seasoned woodworkers than "warped". Boards cup or warp by curving in from side to side, on one face more than the other. This has to do with how the board was cut out of the trunk of the tree in relation to the growth rings. Twisting is a spiral defect which shows up as a rocking at opposite corners. No clamping, wetting or other procedure I have experimented with will get rid of a twist permanently. I am an old timer who has layed panels on the grass in the sun and it works great for warps, but not twists. I have clamped down one corner and put shims under adjacent corners, then clamped the corner diagonal to the first clamped corner to force the twist in the opposite direction. I literally have gone to the point where the wood starts popping and cracking. Sometimes the twist will disappear when I let off the clamps only to reappear some time later. So, after all that, either accept what you have or go to a woodworker and have them shim the opposite high corners so the boards don't rock, tape on the shims to the under side, and run the panels through a wide belt sander with light passes until the face is flat and true. Then flip the panel over, remove the shims and sand out the back. The panel will be flat, but it will be thinner. Hope this helps


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## Improv (Aug 13, 2008)

BernieL said:


> A possible solution for you might be to soak your wood, place them on a cookie sheet with a heavy object on them, and place this set up in your oven set at 325???


325F will do damage to the wood itself and is well above the boiling point of water (212F). Cooking ovens don't hold a constant temperature, but have temperature range as it heats up past the set then cools below the set (not the heating element's color cycle between red and black). 

You don't want to get rid of the water, just make pseudo-steam bending conditions. I've straightened an oak/maple cutting board by heating at 200F in a cooking oven while clamped (8" bar clamps) between two pairs of flat boards running perpendicular to the grain. After ~45min (I forget exactly, just when I thought it had equilibrated with the oven temp), I pulled it out and let it cool for a few hours before unclamping it, then re-oiled it.

Regards,
Steve


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## woodnthings (Jan 24, 2009)

*Help. My board is "warped"*

Warp is another, shorter term for "screwed up" :blink:
It may be cupped, curved, twisted or bent/kinked.
Twisted is the worst, and like MN sawyer said you can't un-twist it. Like herding frogs, it's theoretically, possible but unlikely.
As he said planing or sanding it flat, and therefore thinner is about all that can be done. ..... from an older part-timer.  bill

http://www.woodworkingtalk.com/f2/wood-warping-definitions-10874/


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## dglevy (Feb 3, 2012)

thanks for everyone's replies! this is all very helpful.

You used the term "twist", that is completely different to seasoned woodworkers than "warped". Boards cup or warp by curving in from side to side, on one face more than the other. .....Then flip the panel over, remove the shims and sand out the back. The panel will be flat, but it will be thinner. Hope this helps.

sorry about the term misuse. i am a newbie to the wonderful woodworking world. it is indeed a twist, i.e., the boards rock at opposite corners. they are 1 x 12 x 15; one has about a 3 mm lift and the other, about 5 mm -- not huge, but a bit annoying.

when you tried to eliminate the twist, did you soak the board first? i can certainly imagine that just clamping a dry board would do no good. and i would also think that how long one soaks the board can be important... just a guess.

your idea to use a wide belt sander is an intriguing one. i don't care if the boards are thinner. the neighbor of a friend of mine might flatten the boards for me using his equipment. but he might not. i will ask only when i run out of other options.

Twisted is the worst, and like MN sawyer said you can't un-twist it. Like herding frogs, it's theoretically, possible but unlikely. As he said planing or sanding it flat, and therefore thinner is about all that can be done. ..... from an older part-timer

well, i'm gonna keep trying until all options are exhausted!

You don't want to get rid of the water, just make pseudo-steam bending conditions. I've straightened an oak/maple cutting board by heating at 200F in a cooking oven while clamped (8" bar clamps) between two pairs of flat boards running perpendicular to the grain. After ~45min (I forget exactly, just when I thought it had equilibrated with the oven temp), I pulled it out and let it cool for a few hours before unclamping it, then re-oiled it.

*this sounds intriguing.* was the board twisted? if so, then this might be a possible route. it might be worth the expenditure to get the bar clamps. i can certainly re-use them the next time i bring home a warped...er, twisted... board.


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## dglevy (Feb 3, 2012)

still looking for a solution...


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## dglevy (Feb 3, 2012)

Improv said:


> ....I've straightened an oak/maple cutting board by heating at 200F in a cooking oven while clamped (8" bar clamps) between two pairs of flat boards running perpendicular to the grain. After ~45min (I forget exactly, just when I thought it had equilibrated with the oven temp), I pulled it out and let it cool for a few hours before unclamping it, then re-oiled it.


hey steve, thanks for your reply. can you give me details on this? b/c this seems like the best solution, at the moment. was the board twisted, or was it cupped? have you done this more than once successfully? it might be worth buying the clamps if i think it has a good chance of working.



MNsawyergp said:


> .... I am an old timer who has laid panels on the grass in the sun and it works great for warps, but not twists..... I literally have gone to the point where the wood starts popping and cracking. Sometimes the twist will disappear when I let off the clamps only to reappear some time later.....


did you try soaking the wood before applying the clamps? if so, for how long?


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## MNsawyergp (Jan 31, 2012)

I have been working wood for around 45 years so I was referring to several times rather than once. It is possible to get the wood wet and use steam to re-shape it. There are no guarantees to what shape, though. As the one reply said, he clamped the board between 2 flat boards...I have found that you usually have to go a little extra in the opposite direction. Trees grow to withstand the wind and gravity forces put upon them. They add "muscle" in the form of more growth in areas that need it. When the tree is cut into boards, the saw cuts across these areas and some stresses get relieved. Others don't. When we glue up a panel, a board might have a tiny twist that is not noticable, but add several twisted boards and you get big twisted panels...or a little change in humidity can bring a new shape from an old stress. So, after all this philosiphizing, trying to straighten your panel by wetting and clamping is kind of like putting a dog's tail in a cast and hoping it will be straight the next day. Go with the wide belt sander. You will be much happier.


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## MastersHand (Nov 28, 2010)

MNsawyergp said:


> I have been working wood for around 45 years so I was referring to several times rather than once. It is possible to get the wood wet and use steam to re-shape it. There are no guarantees to what shape, though. As the one reply said, he clamped the board between 2 flat boards...I have found that you usually have to go a little extra in the opposite direction. Trees grow to withstand the wind and gravity forces put upon them. They add "muscle" in the form of more growth in areas that need it. When the tree is cut into boards, the saw cuts across these areas and some stresses get relieved. Others don't. When we glue up a panel, a board might have a tiny twist that is not noticable, but add several twisted boards and you get big twisted panels...or a little change in humidity can bring a new shape from an old stress. So, after all this philosiphizing, trying to straighten your panel by wetting and clamping is kind of like putting a dog's tail in a cast and hoping it will be straight the next day. Go with the wide belt sander. You will be much happier.


I Agree there's to much uncertainty and variables. Not worth the risk

Sent from my iPhone using Wood Forum


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## Itchytoe (Dec 17, 2011)

If you wet the concave side, it will expand slightly and if the warping isn't bad, it may straighten out. Once it's straight, put the mineral oil on it quick and you could end up with a nice straight cutting board.


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## Midlandbob (Sep 5, 2011)

You can't stop wood movement by any clamps or adding moisture.
Wood fibres change in length with change in moisture level which changes with humidity. Radial fibres Change about 1/2 as much for a given moisture change than tangential fibres. This difference accounts for the warping ,cupping and twisting of boards with the almost inevitable changes in humidity over the seasons in most locals.
We can understand and design for the changes but cannot stop them. Some finishes slow the process but even epoxy finish can't stop the eventual change in moisture content and dimentional changes. The wood cups or twists depending on the way the wood was cut from the log and the interaction of the tangential vs the radial fibres. Some trees have unusual wood as they grew on the side of a hill or on an other than vertical direction (called reaction wood). Some trees have fibres that spiral through the tree changing the properties when it dries. This also may account for the twist in some wood.
Any board can be made flat at a given moisture content with jointing and planing but will change in dimension or flatness at any other humidity. The cup of a board can be temporarily straightened by moistening the concave side with water like putting it cups side down on a lawn. Holding wood flat while it dries will build up compression forces in the wood. Unless some fibres crush, it will cup when the holding device is removed.
Cut your losses and work with the wood you have or get straighter wood.
Try to build with wood at or close to the moisture content/ humidity that the piece will be at in use. 
Radial cut wood is the most stable.
Tis topic comes up a lot. Sorry for the rant.
Bob


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## dglevy (Feb 3, 2012)

not a rant at all, bob! thanks for taking the time to share your experience. and thanks to the others who have taken the time to post too, in this second round. 

i'm still working on the problem...


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## Lola Ranch (Mar 22, 2010)

Twisted boards are a common problem. It would be very difficult to correct without any tools. 

With a 2 x 12 x 15" and a 1/4" twist, I would rip it into 3 equal width pieces. I would then flatten one face of each piece then square one edge on the jointer or with a hand plane. Then I would run each piece through a thickness planer making them all the same thickness. Then I would glue them back together matching the grain. You should only lose about 1/8" of thickness overall.

Bret


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## dglevy (Feb 3, 2012)

great! all i need is a jointer, a thickness planer and a garage to put them in, and i'm all set. i've got the glue already.

(sorry, couldn't resist...:2guns


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## woodnthings (Jan 24, 2009)

*lesson learned*

Pick your boards like you'd pick a woman ....curves are good, :thumbsup:
"twisted" not so much. :no: bill


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## Lola Ranch (Mar 22, 2010)

dglevy said:


> great! all i need is a jointer, a thickness planer and a garage to put them in, and i'm all set. i've got the glue already.
> 
> (sorry, couldn't resist...:2guns


That's not quite correct........those tools will fit in the bathroom or kitchen, but yes, you need those tools. You have to re-evaluate your priorities. 

I did say you could use a hand plane which would easily store in your night stand.:laughing:

Bret


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## Itchy Brother (Aug 22, 2008)

MNsawyergp said:


> You used the term "twist", that is completely diffferent to seasoned woodworkers than "warped". Boards cup or warp by curving in from side to side, on one face more than the other. This has to do with how the board was cut out of the trunk of the tree in relation to the growth rings. Twisting is a spiral defect which shows up as a rocking at opposite corners. No clamping, wetting or other procedure I have experimented with will get rid of a twist permanently. I am an old timer who has layed panels on the grass in the sun and it works great for warps, but not twists. I have clamped down one corner and put shims under adjacent corners, then clamped the corner diagonal to the first clamped corner to force the twist in the opposite direction. I literally have gone to the point where the wood starts popping and cracking. Sometimes the twist will disappear when I let off the clamps only to reappear some time later. So, after all that, either accept what you have or go to a woodworker and have them shim the opposite high corners so the boards don't rock, tape on the shims to the under side, and run the panels through a wide belt sander with light passes until the face is flat and true. Then flip the panel over, remove the shims and sand out the back. The panel will be flat, but it will be thinner. Hope this helps


 Exactly like Ive been doing it for quite some time.Shimming and run thru the planer or drum sander.Just break down and buy some good straight wood.


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