Warped glued up panel


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Hi folks,

 

I am refinishing an old drop leaf table. I began last summer with the pedestal and legs and took off the destroyed veneer top on one leaf.  Anyway, I was not able to get back to this project until now. The two other leaf panels are nice and flat and the veneer is good, however, the panel I took the veneer off of is cupped.  Is there a way to fix this?  I don't have much equipment other than hand power tools and don't really wish to make a new panel.  Is it possible to sandwich between plywood or 2x4's?  I can see on the back side there are some gaps in between the glued up boards.  Maybe some glue and clamps?

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What material is under the veneer?  How thick?  I think you can get it straight.  I once straightened out a cupped 6/4 cherry burl slab.

 

Remove the leaf and stack it between evenly spaced stickers both top and bottom (directly over each other).  Stack a piece of plywood on top.  Then stack as much weight on top as you can find; bricks, bags of cement, etc.  Of course, don't stack so much that it cracks your substrate.  Wait a few months and it should be straight.  

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I've read, and tried, one way to fix this.  Take the leaf out to your lawn in the morning.  Lay out a couple 2x4s on the grass and put the leaf on top of them, lay them whichever way has the leaf just above the grass.  Make sure the crowned (or convex) side of the leaf is up, and the leaf is sitting in the sun.  Keep a close eye on it and take it back into the shop when it is flat.  Put it on stickers and let it sit a day or two to see if it remains flat.  If it does, go ahead and finish it on all sides evenly.

 

I assume that the theory behind this is that the moisture from the grass (dew from overnight) will cause the wood fibers on the bottom to swell a bit and the sun on the top will cause that side to lose moisture.  This combination will flatten out the cupping.  I built a table top that ended up warping with the crown up, to the point where a level placed on the crown left about a .5" gap at either end.  I used this technique and the top was flat after 30-45 minutes on the grass.  After a couple days back in the shop it cupped back just a little bit, but only a fraction of what it was.  I sealed it evenly on all sides and it hasn't moved since.

 

One caution is that I did this with completely raw (unfinished) wood, I'm not certain how a previously finished piece of lumber would react.

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I would try removing the veneer from the other face and leave the pice on some stickers to dry.

If you say you can see separation in the end if the board it might be worth cutting up the panel after you remove the veneer and gluing it back together flat to try and avoid any problems in the future. .... Don't forget if you decide to cut the panel every cut you make subtracts the thickness if your saw kerf from your length / width and you'll have to add a strip in so where to compensate.

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