Old question: cupping in cherry panels

[Jerry Olexa]

Glued up some cherry panels for a project. Each panel approx 18"X24". Cupping (about 1/4")across the grain occurs generally on panel where the 11" wide board meets the 7" board . It was joined & glued with biscuits.I have since placed the panel flat on my workbench with weights on top..Are there any tricks, techniques to help flatten,restore this cherry panel to its former self...It will be an end piece in project and will be visible. Hate to discard and start over....Will appreciate your thoughts, ideas. Thanks...

[Prashun Patel]

What's the application? If it's the lid of a chest or the top of a table, I'd flatten, let acclimate, check again, then use the aprons or battens to help keep it true.

Once you reflatten - especially cherry - it shouldn't move as much on you. I have a maple desk that was a 16" + 14" panel. I flattened it once and finished it and it cupped. I stripped the finish and reflattened and it hasn't moved in the few weeks it's been 'live'.

- pp

[mreza Salav]

Would a panel about 1/8" or so less in width be acceptable? if you have a glue-line rip blade (or perhaps a thin-kerf one) you may rip it at the glue joint and redo it.
You may want to flip one of the boards after ripping to lessen this effect.

[Richard Coers]

You sure it's the wood and not from machining or clamping? I always run opposite faces against the jointer fence so if the fence is even off a fraction, it cancels out during the glueup. Bad clamps, or bad technique will make a cupped panel. Lastly is swings in heat and humidity. Place a freshly machined panel on a workbench during a swing in conditions, and one face expands or contracts from air exposure, while air can't get to the other side. Then you get a cupped panel. I stand all glued up panels against something so air gets all around it. I never try to make a panel move, I redo it.

[John TenEyck]

Exactly. If it was flat after glue-up then the warping occurred either because the moisture content in the boards were different from one side to the other, or because you left it lying on your bench with one flat face down. If it was the former, start over. If it was the later, then it should straighten out on its own if you just stand it on edge for a few days. If it was warped when you took it out of the clamps, rip, joint, and reglue.

John

[Jerry Olexa]

All good thoughts...To answer your question, the panel will be used as part of the carcass of a cherry cabinet/end table..I will let it rest with weights for a few days. If not successful, may have to try ripping the joint and reglue etc..Last resort, a totally new panel..I'll continue to read this thread as the process continues..Thanks for your inputs/ideas.

[Lee Schierer]

Try this. Take a wet rag and dampen the concave side and then place the board on blocks with 4-5 inches of free air under it, concave side down. Let it rest for a few days and see what you have. If it si flat always store the panel stacked and stickered so that both sides can breathe.

[Jerry Olexa]

Thank you all ..many good ideas !Lee your idea of letting both sides breathe equally made sense..that has made a difference .. I implemented that into the process and it's now under control ..moving ahead ..thanks again to everyone.

[Lee Schierer]

Thank you all ..many good ideas !Lee your idea of letting both sides breathe equally made sense..that has made a difference .. I implemented that into the process and it's now under control ..moving ahead ..thanks again to everyone.

Don't forget now that your panels are flat, to apply equal amounts of finish to each side to control future seasonal moisture changes.