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I recently built a small 2' x 3' dresser top out of pine. It was within 1/8" flat and level when I glued it up in the garage, but within a few weeks inside it had warped and buckled significantly. What techniques can I use to minimize the chance of this happening in my next project?

Details on the project:

  • I planed several 2x4's down to 6/4 (1.25") thickness, and jointed them with my router and a straight edge.
  • I checked the moisture content at the beginning of the project, and all the boards seemed to be a consistent 12% throughout. I even measured the middle with my pin contact moisture meter when I crosscut the boards to the 3' lengths.
  • I had a business trip partway through the project, and had to leave the unfinished table top sitting in the garage for two weeks. It was completely assembled/glued, but hadn't had stain or poly applied yet. When I got back, the warp had already occurred.
  • I alternated grain orientation on most boards, but I mistakenly put two next to each other with the convex side of the rings facing upwards. The warp is worst here, but there's still a bit of a wave on other parts of the dresser top.

My thoughts for warp mitigation, and why I haven't tried them yet:

  • Use narrower boards? (Not much of an option, since I was working with 2x4's to start with.)
  • Use hardwood? (I'm still a bit of an amateur, and I'd like to perfect my techniques with $10 worth of lumber, rather than wasting money on more expensive stock.)
  • Use quarter sawn boards? (See above reason.)

So what am I missing? Which, if any, of the above options would be most effective to try first? Are there other techniques I can use to mitigate warp in my future panel glue ups?

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Is the humidity in your garage the same as the humidity in the room where the dresser is kept? You can start with a board with 0% moisture content, but regardless of the finish you put on it, it will take in moisture until it matches its environment. I know you can't always do this, but the best way to finish out the seasoning on your lumber is to put it in the room where it will used.

If you're going to use flatsawn framing grade lumber, go through the pile and look for boards that came from the same slab as the pith. (Do not use a board containing the pith itself!) Looking at the board from the end grain, these will have almost straight, vertical grain. These boards are effectively quartersawn.


Image stolen from Wikipedia.

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  • It warped in the garage, prior to me bringing it inside. I had let the lumber sit several weeks in the garage, and when I measured it, it was the same moisture content as a plank of pine that had been there 6+ months. – Doresoom Mar 17 '15 at 17:22
  • Were there any major weather swings while it sat in the garage? – saltface Mar 17 '15 at 17:35
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    Since it's probably enough of a different question, can you take a look at, Why should I avoid using the pith section of quarter sawn lumber? – Doresoom Mar 17 '15 at 17:37
  • Not sure about the weather swings, since I was halfway around the world at the time. :) However, I did let it sit for another few weeks when I got home, and I don't remember any major swings during that time. – Doresoom Mar 17 '15 at 17:39
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If I had to pick a single issue within you approach, it would be the choice of wood. 2x4 lumber is cheap, but is generally not kiln dried. It's almost always a soft wood which increases the chances of the wood warping later on. Soft woods are more prone to wood movement and warping from changes in humidity levels.

So the first thing to consider is using a harder wood than the pine / fir that's typical of 2x4 lumber.

The next thing to consider is letting the wood dry out properly and acclimate to your environment. For 2x4's, I wouldn't think twice of letting the wood sit for quite a few months before even considering using them in a project like this.

Another aspect to deal with is that you need to let the wood rest for a significant period of time after you've planed it down. Again, a couple of months here for the wood to readjust isn't an unreasonable period of time to allow the wood to re-set. In reality, what you're looking for is to see how the wood is going to warp (or not) after the planing. I'd encourage planing down extra planks as some will warp beyond being usable.

From there, you want to make sure you glue up the panels and make sure they are as true as possible. The technique you described sounded like a reasonable enough approach.

At the glue-up, consider leaving the boards a little thicker than what you'd like for the final thickness. Regardless of how well you glue the panels together, you're likely to see some amount of warping. Leaving the boards a little thick makes it easier for you to come back and sand things down to the dimension you want.

Using 2x4 lumber can be done, but it does take a lot more effort and time on your part to get the results you want. It's understandable that you want to keep some controls on your costs while you're learning. I'd encourage you to walk around your lumber supplier's store and see what other options they may have. Those options may cost a little bit more but may not require as much preparation work on your part.

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    Poplar is fairly inexpensive, so it would be a pretty good alternative to 2x4 pine, especially if you're going to paint. It can have some ugly grain & coloring, so it's probably not the best for staining. – FreeMan Mar 17 '15 at 20:19
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The big problem you had in this case was stress wood. by taking 2x4's and planning them down by that much you released stresses in the wood. It was fairly stable at it's dimensions but once changed can release stresses introduced by the kiln drying process. There is a term for this and I can't for the life of me remember what it is right now. But the fast drying of the kiln puts stresses on the inside of the wood. Then ripped or in this case planned down significantly it will show up, some times immediately, others after it has a chance to interact with the ambient moisture in the air.

If you try it again I'd give the wood time to acclimate to it's new dimensions before gluing them up.

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  • You'd consider 1/8" planed off of each side significant? I guess that's something like 17% of the total material, but I never would have thought it would release significant internal stresses. – Doresoom Mar 17 '15 at 16:29
  • @Doresoom ya, for some reason I was thinking closer to 1/4" each side! But since you had that issue, I'm sticking with my answer. Something caused it and that is a known issue. – bowlturner♦ Mar 17 '15 at 16:31
  • but once changed can release stresses introduced by the kiln drying process. There is a term for this - It's called case hardening, brutal in maple, not so much in pine. Mind you, I've never planed pine 2x4s. Air drying is best, but unrealistic for factory wood. – brian Apr 13 '15 at 3:54

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