Panel with breadboard ends question?

[Bill Huber]

I have a panel, 26" x 48" x 1", coffee table top, it is made of 5 ash boards all doweled together about every 4".

The problem:
The glue up went good, scraped the glue and the panel was nice and flat and I was very happy with it.
Set it aside to do some other work on the table and when I came back to it 2 days later it was bowed.

Over the 26" width there is almost a 1/16" bow. I was able to clamp on edge a board with quick clamps and it flattened it out.

The question:
The next step was to cut the tenons for the breadboard ends.
Will I be able to pull it flat with the breadboard end or not.

Should I take it to a cabinet shop and have it flattened before I go on with it?

[Danny Hamsley]

If you stand it up where it can get good air flow on all sides, it might relax on its own. If it laid flat for two days, with one side flat on a surface, the topside side lost a little moisture, but the bottom side did not, therefore the change in dimension. However, if you stored it so that air could circulate all around and it still bowed, then it might not relax on its own without some help from you. You might be able to turn it over stored flat on a table with the opposite side down and it might straighten up. Hopefully, you will not have to go the cabinet shop route.

[Bill Huber]

If you stand it up where it can get good air flow on all sides, it might relax on its own. If it laid flat for two days, with one side flat on a surface, the topside side lost a little moisture, but the bottom side did not, therefore the change in dimension. However, if you stored it so that air could circulate all around and it still bowed, then it might not relax on its own without some help from you. You might be able to turn it over stored flat on a table with the opposite side down and it might straighten up. Hopefully, you will not have to go the cabinet shop route.

I stored it so air could get to all sides, not flat, found out about that some time ago.

I may have caused the problem, I started with 5/4 and planned the boards down to just over and inch, then drum sanded them to an inch. I only let the board set for a day before I did the glue up and I think I should have let them set longer.

But now I just may try to lay it flat and see if it will flatten out. I think I would want to lay it crown up, right?

[Judson Green]

You should be able to just proceed with your build, I would. The breadboard ends will straighten out and help to keep straighten out your panel. I wouldn't worry the least about 1/16" cup in 26".

Out of curiosity did you plane/sand approximately the same amount from both sides of the boards? Removing the same (or nearly the same) helps to keep the core (slowest to acclimate) of the board in the same relative place. Also, drum/wide belt sanders generate a lot of heat on the surface your sanding which could have an impact on cupping, best to do both sides. Balance out the core.

[Jerry Miner]

I'm with Judson. I would proceed, but while keeping the cup in mind. Clamp it flat to machine the tenons. Your table aprons should be able to hold it flat once attached.

[Brian Holcombe]

Also with Judson, in the past when I have built with breadboard ends they've straightened out slightly cupped glue ups. I'd flatten it by hand after the breadboard ends are on, you might find you just need to take out a slight bit.

[Howard Acheson]

Sticker the panel so that air can easily get to both up and down surfaces. If you placed the panel directly on a surface after you planed and sanded it it probably has absorbed moisture unevenly due to one surface being against another surface.. Use stickers and put some weight on the top of it.

Do not count on bread board ends flattening the panel. The BB ends may flatten the panel close to the BB ends but they will only minimally affect the center section of the panel.

[Robert Chapman]

I'd put two or three cross pieces across the width of the table in addition to the breadboards. Secure the cross pieces with screws in slotted holes to allow for expansion/contraction.