wood bowed after planed#$%$%$#!!! help!!

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Forum topic by wireless28806 posted 02-25-2009 03:34 PM 5635 views 0 times favorited 13 replies Add to Favorites Watch
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10 posts in 2810 days

02-25-2009 03:34 PM

Topic tags/keywords: question

I bought a piece of walnut at a lumber yard, fairly straight. A couple days later planed it then cut two pieces 30”X2”X3/4”... I set it down, and two minutes llater, it had bowed. It was quite cold in my shop, could this be why? should I have clamped them together for a couple days, and hoped the pressure would straighten them?

What was wrong? Anybody ever have this problem? What did you do?

13 replies so far

View Peter Oxley's profile

Peter Oxley

1426 posts in 3296 days

#1 posted 02-25-2009 03:46 PM

The cold could be the problem. Also could be the result of planing significantly more off of one side than the other.

What are you going to use these pieces for? Are they going to be attached to something that will pull them flat?

-- -- --

View CharlieM1958's profile


16229 posts in 3639 days

#2 posted 02-25-2009 03:57 PM

If I’m not mistaken, I’ve read that a board dries from the outside in. Planing or resawing a board can expose the moister interior, leaving you with a board that is drier on one side than the other. Rssult: rapid warping.

If this is the case, your board should straighten out when the moisture content equalizes.

-- Charlie M. "Woodworking - patience = firewood"

View PurpLev's profile


8523 posts in 3070 days

#3 posted 02-25-2009 04:20 PM

out of curiosity – did you plane the board on both sides? or just one?

if you planed it only on one side, then that side introduces new moisture levels on the board, while the other side (not planed) stays the same – and the differences cause the board to bow.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View wireless28806's profile


10 posts in 2810 days

#4 posted 02-25-2009 04:35 PM

I planed both sides. I dont have a jointer, so I attached the wood to a 3/4 piece of plywood to secure it tightly, then planed one side, then took the piece off and planed the other side. I figured I had both sides flattened. It was after I ripped it into 2” pieces that this bowing occured.

Thanks for the replies..

View Blair Helgason's profile

Blair Helgason

169 posts in 2835 days

#5 posted 02-25-2009 05:36 PM

I am by no means an expert but I was just yesterday watching Marc Spagnuolo talk about rough cutting you lumber in length and width then planing it. It’s very common that some pressure will be released when cutting a board to width. Just a thought.

-- Blair

View PurpLev's profile


8523 posts in 3070 days

#6 posted 02-25-2009 05:58 PM

true, when you rip lumber, it will release some tension in the wood (thats why some people will swear by ripping rough lumber on the bandsaw as opposed to a table saw). it is not uncommon for rough lumber to get out of ‘square’ after initial milling. a good general rule of thumb, is to do your initial milling slightly larger then your finished dimensions, and let the wood sit in the shop before milling it to final dimensions – since milling the rough lumber introduces new stress points and moisture levels in the wood in different ways and might end up – like you’ve noticed – getting the wood out of straight.

This is all nice and theoretical, but as a suggestion, I’d let the wood sit for a while (1) get it used to the new environment, and (2) see if the cupping will minimize at all, and after that , I’d consider milling it again to straight, and maybe redesign all other pieces to match the new milled pieces in size (if that’s at all reasonable to you). I haven’t heard, nor experienced any success stories of straightening boards and winning over the boards internal bonds – unless you are able to steam/bend it I guess…

P.S. I can’t tell exactly how you ‘secured your board to the plywood tightly’ and what it really means- but make sure that you don’t secure it in a way that will ‘temporarily remove’ it’s bow/twists/cups cause that will just make them pop back into the board once you remove it from the plywood. I’d search here for planer-sleds (or google it) if you havent yet done so to see how other’s are doing it.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Boardman's profile


157 posts in 3182 days

#7 posted 02-25-2009 08:23 PM

If you planed both sides it’s most likely “reaction” wood – wood that was under some stress on the tree, such as a curve in the trunk or a leaning area. When you planed it, it released sthat stress. It probably that because walnut is usually pretty “tame” – doesn’t move much at all. That’s also why limb lumber is not used even if the limbs are big, because of all the stress of supporting the smaller limbs and leaves.

View ShannonRogers's profile


540 posts in 3209 days

#8 posted 02-25-2009 11:30 PM

‘nuff said above, so all I can say is ditto. I feel for ya, I’ve been there too.

-- The Hand Tool School is Open for Business! Check out my blog and podcast "The Renaissance Woodworker" at

View Julian's profile


880 posts in 2947 days

#9 posted 02-26-2009 12:49 AM

If it was kiln dried too fast it could also develop tension that will cause the board to bind against the blade while cutting. I have bought way more internally stressed wood from my local hardwood supplier than I’d care to admit. This is one of the reasons I built a solar kiln, so I can control how it is dried, and of course to save some money.

-- Julian, Park Forest, IL

View Big_Bob's profile


173 posts in 3130 days

#10 posted 02-26-2009 01:20 AM

Just to tag up with everyone else wood does not move do to temperature changes to any great extent. Moisture will cause it to move or it can stress relief it self if it is under stress. I live in a dry climate I can not buy wood and use it right away. I have found that if I order wood from the small mom and pop saw mills that kiln dry their wood I get a pretty good product. But when I buy wood from a big box store or a large hardwood supplier I need to let it dry out for a few extra weeks (like four to six) before I work with it. The big box store needs to turn over their inventory fast so dry wood is not on their priority list of things to do.

-- Bob Clark, Tool Collector and Sawdust Maker

View juniorjock's profile


1930 posts in 3187 days

#11 posted 02-26-2009 02:46 AM

I’ve watched wood warp as I was ripping it. At least it was warping away from the blade. I’ve noticed that most of the time, there’s a knot involved.
- JJ

View Karson's profile


35032 posts in 3822 days

#12 posted 02-26-2009 05:09 AM

I feel for you. I usually cut large and then trim to size after aging a little.

How much was the bow?

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware soon moving to Virginia †

View 8iowa's profile


1540 posts in 3182 days

#13 posted 02-26-2009 05:20 AM

In “Woodworking Wisdom” by Nick Engler, the author recommends letting wood “climatize” in your shop for at least two weeks in order to let it’s moisture content reach equilibrum with the surroundings. actually longer is better. Puting recently acquired lumber to the cutters is just asking for problems like this.

In my Upper Peninsula shop I have a loft that has a main purpose of storing and drying wood. Down in the shop I have a wood rack strictly for the purpose of letting wood climatize for upcoming projects.

-- "Heaven is North of the Bridge"

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