Thread: Correcting a bowed board on a desktop

Sorry to say, but I think your solution will only be a temporary one. It may take some time, but eventually you will get glue failure in the same spot (photo 2) as the boards will contract and expand along its width. The spline will delay it a bit longer but the problem is the short boards at the end has its grain perpendicular to the rest of the boards and they won't expand at the same rate as the rest of the boards (boards expand and contract more along its width then its length). The long term solution is to replace the short end boards with longer pieces that extend all the way to the edges installed a lá breadboard ends (see pic below).


breadboard ends.jpg















or........


BreadboardEndJoint1.jpeg


















You should also alternate the orientation of the growth rings of your edge-jointed boards to minimise cupping (see below). This obviously does not apply to quarter-sawn boards.


end_grain.jpeg











Cheers,
Mick

If you don't like the look of breadboard ends and you really have your heart set on the frame and panel look, then you have two options:

1) Actually make it a frame and panel construction where the panel (the piece in the middle) sits within grooves inside the frame and is sized accordingly to allow expansion and contraction within the grooves. This means having a "shadow gap" on the inside of the frame (similar to the 2nd from the bottom in the pic below).

FrameandPanel5.jpeg





















2) Use a stable and engineered material for the panel, e.g. veneered MDF or plywood. No need to have a gap for expansion. You probably wouldn't even need grooves or tongues. You could probably get away with gluing the frame directly onto the panel.


Out of the 2 options, I would go for #2 for a desk or table because grit and dirt will fall between the gap. That would be a real hassle IMO.