Warping question

[Joe McMahon]

I am building an armoire from quartersawn white oak. It is a large piece and is solid QSWO. My problem, and my question has to do with the single door. It is a large piece, 29" X 56" rail and style construction with two panels. The rail and stiles are all 1" thick and the panels are 3/4" thick, setback 1/4" from the front, the stiles are both 6" wide and the top and bottom rail are 6" wide, with the center rail 5" wide.

To make up the panels, I bought a large piece of 8/4", 10" wide by 50" long. I resawed the piece into two 3/4" halves. I then bookmatched the halves forming a large panel which I crosscut into the two panels that I would need. I then sized both panels and left them for a week. From fear of warpage, I clamped them flat on my bench. You guessed it, they both warped. The panels are 18" wide. If I hold one edge on the bench, there is a 3/4" gap under the opposite edge. Since they are to actual size, I can't cut them and reglue.

I have to cut a rabbet around all four panel edges, each 3/8" thick and wide. They will fit into a 3/8" dado which is set back 1/4" from the front of the stiles and rails.

Now to my question: Am I inviting trouble if I force the panels flat into the dadoes cut into the stiles? I will have only 1/4" of material on each side of the tongue.

[Mel Fulks]

I would reduce the thickness by removing wood only on the convex side. That will make them flatten some and flex easier.

[Alan Schwabacher]

When they were clamped to the bench, did you use spacers to make sure both faces were exposed to air? If not, that could have caused the warping by allowing moisture content to change more on one side. If the starting stock had a different moisture content in the interior than exterior, resawing would have left them unbalanced and prone to cup. They may flatten out as they equilibrate.

How much cup you can expect to take out by capturing in a frame is something that will take a more experienced answer.

[Brian Holcombe]

Joe, I wouldn't want to force a 3/4" panel flat. IMO but if you can live with it I'd cut them thinner. Thick panels are trouble makers and add a lot of weight to the finished assembly.

I know its tempting to glue a panel immediately after resawing but experience has taught me that they should be left to acclimatize for a few days prior to working on them.

[Joe McMahon]

I will probably end up planing the panels thinner. The cost prohibits another attempt. This was my first resaw of so large and thick a piece of wood. Next time I'll give a few days to acclimate before gluing. They may have picked up more moisture on the side that was flat to the bench.

[Robert Engel]

QSWO should behave so I'm thinking to have this much warp in a 10" wide board, the MC gradient had to be very high, ie, the wood was even close to being seasoned

OR

The wood was clampled to the bench with no stickers (especially if the sawn faces were down).

You could try wetting the concave surfaces, but I wouldn't be too optimistic about it in a board this thick.

Resawing always opens the center, higher MC wood so keeping the stock flat (with either weights or clamps) with adequate, even air flow is even more critical. I usually keep the resawn surfaces opposite each other so as to balance out the forces when stickering. With resawn wood I generally have 2x cauls top and bottom of the stack. Be sure to have stickers between cauls, too. Then I tape, strap or clamp the pile and move it to an appropriate area of the shop. I have resawn 1/4" drawer bottom panels they will be flat one day and if I leave it on the workbench, will be cupped the next.

I would suggest 3 millings, each time jointing/planing = to 1/16 off each side and resticker for a week. I would take into consideration the climate of your shop if humidity swings are a problem I would store the stickered stack inside. After final dims are reached, you can put them in a plastic bag for a few days for final stabilization.

I agree with Brian re: thickness. 3/4 is going to add considerable weight to the door this size, so you're better off planing down to 1/2" or so.

[Tom McMahon]

Joe, thinning the panels will work, but if you want, the panels can be straightened. Here is a link to an article I wrote on straightening a warp.
https://millcrek.wordpress.com/2012/08/16/straightening-a-warp-compression-set/