Three boards really close to the pith, in the center too, will do that. Those also look pretty wide, which only exacerbates the problem. How long did you let these dry after milling? Were they all totally flat when you glued them up?
Unfortunately there’s no saving it in its current state. Your best bet is rip all three apart, then rip the three boards in half, ideally removing the center inch or two (the area most prone to cupping) when you do so, and regluing the now 6 pieces
You've probably forgotten more than I'll ever know about woodworking but ... are the grains on all three boards running in the same direction? Shouldn't the middle one face upside down?
That can help but if the amount of cupping is this extreme, as it is here, all you'd do is make the top wavy like a flattened W instead of a C. The end boards will still cup, the center board will cup, it'll just be less noticeable since the ends go up and the middle goes down. This one is so extreme that it'll be noticeable. If it were 6 thinner boards, the undulations would be more subtle.
83
u/thoang77 5d ago
Three boards really close to the pith, in the center too, will do that. Those also look pretty wide, which only exacerbates the problem. How long did you let these dry after milling? Were they all totally flat when you glued them up?
Unfortunately there’s no saving it in its current state. Your best bet is rip all three apart, then rip the three boards in half, ideally removing the center inch or two (the area most prone to cupping) when you do so, and regluing the now 6 pieces