Cupping in edge-jointed build-ups

[Aaron Rosenthal]

Many years ago, I was given the chance to take all the solid Oak off some pews that were going to be trashed at the dump. Naturally I worked into the night to harvest as much as possible. I stored it in the rafters of my garage, and kept busy making a sort-of-living.
I've begun to use some of the wood.
I'm building a free-standing cabinet for electronics storage (DVD player, cable box etc) with edge jointed pieces; glued, clamped, cauls, then planed and smoothed.
The panels are bowed, I'd say 3/16 to 1/4".
The case will be fitted with a plywood bottom, and will have 2 shelves dadoed into the sides; I'm making a 3 board sub-top for the solid build-up top piece.
I can clamp the ever-luv'n heck out of the shelf/case, and make it seat, but i'm concerned the wood will move to where the joint loosens when it's completed.
I could use a suggestion or 3.
Aaron.

[Lee Schierer]

Are thes board cupped as they come from your storage or are you surfacing them?

Were they stored stacked and sticketed? What sort of storage area?

[glenn bradley]

Assuming the cupping is related to joinery; you mention edge jointing but, no face surface prep. In order to accurately edge joint you need a face jointed surface to use against the fence as a reference. Deviations in the face can cause undulations in the edge or other anomalies.

Assuming the cupping is related to stress release or moisture shift; surface prep the boards to over-size, let acclimate a couple of days and then mill to final dimension just prior to glue up.

[Derek Cohen]

Aaron, I imagine that the panels have bowed as a result of one side drying more while in the rafters of your garage. If this is the case, it is worth wetting one side to equalise the moisture, and see if it will return to flat.

Regards from Perth

Derek

[Aaron Rosenthal]

Are thes board cupped as they come from your storage or are you surfacing them?

Were they stored stacked and sticketed? What sort of storage area?

Lee, narrow boards, about 3” wide. Removed the bullnose with the table saw, straight out of the stack. No, storage not optimized but yes, reference surfaces checked and good.