Solid Wood Dresser Tops - Warping

[Larry Frank]

I am building a bedroom dresser and the top is about 20" by 36". I am planning on using quarter sawn red oak and edge glue the boards to get the 20". I have made some other projects using this technique and found that I get less warpage by keeping the boards less than about 4" wide for glue up. I am concerned about warping later on. On some projects the top has stayed very flat and on others, I have had some general warping where the edges of the top warp up slightly.

What is the best technique to minimize this warping?

[Lee Schierer]

Quartersawn lumber should be less prone to warp than plain sawn lumber all other things being equal. Make sure the lumber is properly dried and that you allow for seasonal changes in the top and warpage should be minimal.

I would also recommend applying equal amounts of finish to both sides of your top before it is permanently installed. This will slow moisture changes which should limit warpage.

[Mike Null]

I second the "finish both sides" plan. I've done a few things including a 54" round table without any warp at all. The table is now about 12 years old, in daily use in our kitchen. We also have high summer humidity in St. Louis.

[Russell Hudson]

I go so far as to make sure that the boards sit for a few days in such a way (not stacked on top of each other) so that both faces are exposed to the air before planing, during glue up up until the 'counter top' is finished both sides. And even though quartersawn is less likely to cup, I still try to vary grain direction (as seen from the boards ends) from one board to the next. Correctly kiln dried lumber (14%?) should help minimize the problem and I know carpenters who like to have material left at the site for a few days before they begin construction so the wood acclimates to the moisture level of the place the unit will be in.
One more thing ...... The more 'select' the wood (less knots, less swirls, more even colored) the less likely it is to warp in any direction.

[Danny Hamsley]

If the wood is fully dry for your application and in equilibrium with the in-use environment, it will not warp. It will only warp if the wood is still losing or gaining moisture. Getting the wood good and dry is your best ammunition. Then, like the others said, keep both sides equally exposed to the air when you are not working on it. I generally wait until the very last to make a top, and then install it as soon as possible. My shop is not air conditioned, and I am in Georgia. My biggest challenge is always managing moisture content.

[Kent E. Matthew]

Is a bread board edge on each side out of the question?

[Gene Crain]

6-8% MC. Equal finish schedule both sides. Attach top with a method for movement because all wood no matter what specie or milling or MC, will move, period.

www dot woodweb dot com has a great calculator for specie wood movement with changes in RH%

Gene

[Larry Frank]

Thanks for all of the replies. The one tool that I do not have is a moisture meter. I took a look and the prices are all over the place. Can some one recommend a reasonably priced one that works well.

[John Keeton]

Larry, I have used the Ligno-Mini for several years and like it. I think it is available around $100 - 110. Simple and accurate. It does have pins, but that isn't usually an issue for me.

[Jim Becker]

I prefer and generally use the widest stock I can get for larger surfaces...and I don't have any issue with "warping" if the lumber was dried correctly and the project is build with wood movement in mind. IMHO, the "keep the boards narrow" thing is a myth and it can also make for a less attractive project result, especially with figured material. For a dresser top, that means fastening it to the casework in such a way that it can move seasonally, but is still held down to the case in a "seemingly" stationary position. There are a number of ways to do this, but they all have something in common: the top can move across the grain unrestricted by mechanical means and that also means no glue between the top and the case. I construct so that "expansion" movement is toward the back of the piece since that's generally away from the viewing angle on most furniture of this nature.

[John Downey]

I'm with Jim on this, wide boards are more attractive to my eye, and there are many ways of controlling cupping depending on your design - bread board ends being one already mentioned. Design to allow cross grain movement and restrict cupping, and as long as the wood is less than 10% MC, you'll be fine regardless of board width.

[Tony Bilello]

My first suggestion is find a new lumber supplier and dont look for discounts.

Now for my question to you......is this a warping problem over time or is it warped when you take it out of the clamps. If the later is the case, then you are not getting a 90* cut on the edges. There are techniques for eliminating this, one of which is to flip and reverse every board.
If the warping is over time, buy a better quality lumber.

[Howard Acheson]

The reason for the warping is that the underside of the board does not get free access to the air in the room. This causes the top surface and the undersurface to be at different equalibrium moisture content levels.

The first thing is to be sure that the boards are at equilbium with the environment in which the furniture will be used. After glue up, and before final assembly, store the panel on stickers or on edge to allow air to get freely to both sides.

Finish both sides of the panel equally.

Finally, use an attachment method that will hold the panel flat but still allow it to expand and contract with seasonal changes in relative humidity. In most cases, proper fastening should hold the top flat.

Finally, when you install the item, leave the doors open and the drawers out for a couple of weeks to allow the panel to equalize to the area.

[scott vroom]

I'm with Jim on this, wide boards are more attractive to my eye, and there are many ways of controlling cupping depending on your design - bread board ends being one already mentioned. Design to allow cross grain movement and restrict cupping, and as long as the wood is less than 10% MC, you'll be fine regardless of board width.

What are "bread board ends"?

Thanks

[Chip Lindley]

Use of too-wet wood is the #1 culprit in warping IMO. IF kiln-dried wood has been acclimated in the shop for 30 days (or better still inside the house where it will reside) there should be no warping except from reaction wood stress. Reaction stress is built into the wood and cannot be avoided.

Reversing the growth rings (smile/frown/smile/frown) of alternate boards in a wide glueup with square jointed edges is some of the best insurance against cupping. Allowing for expansion in the attachment to a carcase or use of battens on the underside (in the case of a chest top) are another.

[John Downey]

What are "bread board ends"?

155157

Borrowed from another poster in this thread:
http://www.sawmillcreek.org/showthread.php?t=116387
He's got good advice for construction too.

Google images lead me right back here :D

Try googling "bread board end table" in images for more pictures of furniture.

[Tony Bilello]

What are "bread board ends"?

Thanks

Scott, here are 2 sketches I made on a different forum, but it should give you the general idea.