I read recently that traditional Japanese furniture makers use water on cupped boards and/or hold the boards over fire to straighten out. Anyone have any info on this process? It seems like a nice way to avoid wasting valuable wood.
fixing cup & twist with water, fire?
Nov 14, 2003
5 Replies
I've managed it with a spray bottle of water and a portable electric heater with a fan. Timing is everything :-)
-Doug
I just took the cup out of a couple of raised panels this morning by painting some water onto the concave side then sitting the piece concave-side-down on the laminate clad top of the outfeed table.
About a half hour later the pieces had straightened out enough to be machined.
In the past I've used a heat gun on the convex side of finished material that had bowed and that worked well.
The trick is to get it as soon as it goes flat and then put extra finish on the convex side, to keep it from re-absorbing moisture and returning to it's bowed state.
Regards, Tom Thomas J. Watson-Cabinetmaker Gulph Mills, Pennsylvania
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Doesn't that just postpone the return of the board to its preferred state (bowed)?
Thank you.
In fairness, however, wood does have a tendency to take a "set," a characteristic we take advantage of in bending. Trouble is, unless it is restrained properly, it will return to close to the unrestrained state after a few cycles.
In the first instance I was only interested in getting the cup out of the raised panel blank long enough to machine the bevel. The frame was enough to restrain the cup once the panel was inserted.
In the second instance, spraying the formerly convex side of the panel with two extra coats of finish seems to have worked fine.
Regards, Tom Thomas J. Watson-Cabinetmaker Gulph Mills, Pennsylvania
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