Is there a way to get the cup out of resawn pieces?

[Wayne Jolly]

I just resawed a piece of 11" wide 4/4 Quartersawn white oak. I think this is air dried lumber but I am not sure about that. The two halves have cupped so badly that I can't use it like this. Is there a way to flatten the pieces so they will remain flat? I intially thought I might just mist them with some water and then weigh them down flat, but I don't think that would work. I thought about just throwing them in my pool for a few hours before weighing them down, or maybe just putting them in a 250 degree oven for a while maybe with some water in it to "steam" them??), or maybe boiling them, or maybe steaming them with some carrots and onion, etc. I want to cut them into smaller pieces to use in some frame and panel doors. The doors will be about 30" tall and each will be about 15" wide. There will be three panels per door with the largest panel being about 8 1/4" x 10 1/4". So whatever the case, I need them to be stable afterwards.


Thanks,

Wayne


P.S. The photo was taken yesterday and the cupping is a little worse today. The cupping is pretty strong too. It took 4 2" Bessey spring clamps to get the gap closed enough to be useable.

[Ted Reischl]

One thing you could do is rip them down the middle. Then plane them flat. Doing it this way reduces the amount of lost thickness. After flattening, edge glue them back together. Then clean up.

Of course, none of this may work for you if there is not enough thickness left.

BTW, take light passes when replaning to avoid taking the bow out only to have it pop back.

[John TenEyck]

If they cupped because of internal stresses you have no hope to flatten them. If they cupped due to uneven moisture content then they may flatten out in a few days. Leave them on edge or stand them up against the wall so air can circulate all around them - and hope.

John

[Keith Hankins]

When I do resaw, I put them back to back wet side out. Clamp/tape what ever, and put them in a plastic bag for a couple days to slow down the drying uneven. Some times depending on the dryer it's just a lost cost. I've had some boards jump to a rainbow in a couple min. Good luck.

[Rich Enders]

What John said seems solid to me, and based on the weather you have been having there is a good chance that uneven moisture is a problem and letting the re-sawn boards come to equilibrium will improve the situation. However it is doubtful that they will become totally flat because re-sawing has allowed internal stresses to exercise their muscle.

Salvaging these boards per Ted's idea, and/or planing them at full width (a little thickness at a time with 24-48 hours between cuts) may be required. If you wind up with panels that are too thin they can be glued to each side of a plywood "panel" to regain your desired thickness.

I was able to re-flatten some white oak drop leaves on an antique using a form of your ideas by keeping the concave side damp (for 6 months) and then slowly allowing them to dry completely. However these probably had no internal stresses and it was just a moisture imbalance caused by the finish having disappeared on the top surface only.

[Clay Fails]

I just resawed a piece of 11" wide 4/4 Quartersawn white oak. I think this is air dried lumber but I am not sure about that. The two halves have cupped so badly that I can't use it like this. Is there a way to flatten the pieces so they will remain flat? I intially thought I might just mist them with some water and then weigh them down flat, but I don't think that would work. I thought about just throwing them in my pool for a few hours before weighing them down, or maybe just putting them in a 250 degree oven for a while maybe with some water in it to "steam" them??), or maybe boiling them, or maybe steaming them with some carrots and onion, etc. I want to cut them into smaller pieces to use in some frame and panel doors. The doors will be about 30" tall and each will be about 15" wide. There will be three panels per door with the largest panel being about 8 1/4" x 10 1/4". So whatever the case, I need them to be stable afterwards.


Thanks,

Wayne


P.S. The photo was taken yesterday and the cupping is a little worse today. The cupping is pretty strong too. It took 4 2" Bessey spring clamps to get the gap closed enough to be useable.

wayne, I posted the exact same issue a month or so ago. You can probably find it and all the helpful replies if you search. In my case it was definitely internal stresses. The boards cannot be re-shaped without milling, and there is not enough thickness remaining. I think there is something about QSWO that makes it more susceptible to springing like this after resawing.

[Wade Lippman]

I had a 6' long piece of bowed walnut. I clamped it to a beam with reverse curve for a year and periodically steamed it. When I took the clamps off it went right back to how it was before.
Good luck trying that process.

[Wayne Jolly]

Thanks for the replies. I am almost certain that the cupping is due to stress relief and not moisture. I brought the pieces into the house last night where it is much drier, and the cupping even got worse. I figured it was stress relief because I even saw the cupping before the resaw was done. I cut about 6" and then backed out. I could already see it was cupping on the cut end.

Figuring I had nothing to lose, I put one of the halves in a 250 degree oven with some boiling water for about an hour. I took it out, ran it out to the garage and put about 20 pounds of weight on it. 20 pounds of weight wasn't even enough weight to remove ANY of the cupping. Since this is a Christmas present, I guess I am looking for another option.

Clay - Before I posted this, I did a few searches for this problem and did not find any appropriate threads. Can you direct me to yours??

Thanks again,

Wayne

[Jason Beam]

Since it cupped right away, i suggest going thinner and turning it into veneer. You won't show the wood who's boss any other way - it'll show you

[Roy Harding]

As others have said - that's the way the wood wants to be, you can fight it, but you will probably lose.

A possible solution to your problem is to rip the boards into narrower widths, joint them flat and square, and then glue them back up into a panel. This will preserve a lot of the thickness, and if you keep the pieces in order, the final glued up panel will appear almost natural (the grain lines will almost be in sync - enough to fool the casual eye).

An alternative is to rip, joint, and glue them back together in book matched orientation. Although this won't preserve the natural look, it will add visual interest - depending upon the grain.

I do a LOT of glued up panels - and the book matching option can be spectacular.

Whatever you decide to do - best of luck to you.