Board cupping and twist
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I am currently working on the garden bench project. I prepared the long rails to final dimensions. After a few weeks I finally got up to cutting the tenons and noticed significant cupping and even some twist. If I take out the cupping my rail will be too thin. Any advice on possibly salvaging the piece of wood and how to prevent in the future? Any thoughts if keeping the rails clamped tightly straight and together would have prevented the cupping from developing?
I’m having the same problem with wood cupping soon after planning. Anyone here have a solution to this problem?
Hi Chai, I did a little research after posting this topic. In my case I was using 1 &1/2 inch stock, removing 1/2 inch to a final thickness of 1 inch. In my case, the wood most likely wasn’t completely dry. After removing 1/2 inch of thickness, the newly revealed surface was wetter than the outer surface which was exposed to the environment for longer. When wood dries, it contracts towards the face that is releasing more moisture. It seems one solution when reducing a boards thickness significantly is to leave on an extra 1/8th inch or so and let it dry and do its thing for a few days at least. After it finishes settling ( in my case it was cupping and twisting) then remove cup and twist and plane down to final thickness. It should remain stable at that point.
Nicholas,
You’re likely correct in your assessment of the wood movement you describe. In addition to moisture loss, you likely exposed some internal tension in the wood through planing. This is to be expected especially if your wood is kiln dried.
1/2 inch is quite a lot of wood to remove. You’d be better served to start with stock closer to your final dimension. Alternatively, you may have better success if you removed 1/4 inch from each face rather than 1/2 inch from one.
Another option is to plastic wrap your piece(s) after planing them to prevent moisture loss until you’re able to cut your joinery. I believe Mr. Sellers does this in the “Chest of Drawers” project.
If your dimensioned piece is significantly wider than it is thick, you may also wish to stand the piece on edge rather than lay it face down for storage to allow air to circulate more evenly around the piece.
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