My little knitting needle box project is driving me crazy before I’ve made the first cut.
I bought 5/16 aromatic cedar at Rockler and 10 months passed before I had time to start the work. I found the whole 8-foot piece had cupped badly.
I went out and bought some 1/2″ aromatic cedar stock at Austin Hardwoods last week; beautiful pieces, perfectly smooth and true. Today I find the piece that would be the top and bottom of my box is cupped 1/32″ over the 6 3/4″ width. The 4″-wide x 48″ piece for the sides I planed down to 3/8″ thickness last Sunday and it has now bowed severely on the newly planed side; laid down flat, each end curves up about 3/4″.
At the moment I have both boards laid on the bare concrete of my garage floor in hopes of absorbed moisture straightening them, but that’s probably only a temporary fix.
I planned to cut a 1/4″ rabbet on top and bottom before gluing to the finger-jointed sides. Assuming I can press them flat while routing the rabbet and glue joints hold, I’m afraid that the top at least would cup again. After cutting the top off the box, there would be only perhaps a half inch of the 3/8″ end material to resist the top board cupping.
Any suggestions?
Replies
You aren't by any chance leaving the boards laying flat on the work bench between times when you were working on them. It may well be that they needed more time to acclimate themselves to your shop's moisture. For that they are best stickered and allowed to reach equilibrium at the new moisture level. You may still find that the boards will straighten themselves out if you give them the desired time to adjust--which could easily be several weeks if your shop humidity differs by very much from the levels where they had been previously stored.
The wood was stored standing on end leaning against a wall with other lumber.The lumber yard is only 13 miles from my shop and the wood there was stored in stacks standing on end. We did have a Santa
Ana wind condition (warm dry air flow from the deserts) on Sunday/Monday, but humidity in Orange County is normally in the 30% to 40% most of the time. BruceT
bruce,The wood was stored on end at the lumber yard? That's unbelievably irresponsible for a lumber supplier. Maybe it was placed there while being moved, shortly before you bought it, because it's hard to believe they could have kept it flat stored that way.It should return to flat by acclimating stored flat on stickers - narrow strips of wood (about 1" x 1" x whatever length needed to hold the width of the lumber) placed under the lumber, about 10" apart, and on top of the lumber directly above the lower stickers. If there's only one board, place a heavy board on top of the top stickers and weight it. If there are several boards to flatten, stack them up with additional rows of stickers, all lined up vertically in the stack.The stickers allow air to flow around the boards so that they can come to equilibrium with the ambient average humidity. If they flatten out, the finished piece should also stay flat.Rich
Edited 12/10/2008 8:09 pm ET by Rich14
"The wood was stored on end at the lumber yard? That's unbelievably irresponsible for a lumber supplier."Really? All the lumber yards around here keep hardwood and trim stock standing on end; Ganahl Lumber (the biggest), Orange Coast Hardwood, Austin Hardwood, Rockler, and of course big box stores. It facilitates the customer selecting the pieces he wants for a project.BruceT
bruce.Not intending to start a war. Maybe stock moves so fast at those places that it doesn't matter. I'm used to seeing lumber stored flat.I lived in Orange County and I remember now seeing lumber stored as you say at several places in Santa Ana (can't remember the names).In other places, including Hawaii, that was not the case.Rich
I grew up with those Santa Ana winds, they are evil, just plain evil. My condolences, hope you solve the wood problem!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
My guess is that the wood you are buying is at a higher equilibrium moisture content than your shop. When you get the wood it dries unevenly and without any weight on it. I'd plan to buy thicker wood and plain the cup out of it.
Regards,
Roger
Rockler and Austin Hardwood are both about 12-13 miles from my place and inland where the climate is hotter and a bit dryer. I live 2 miles from the ocean where temperatures are 5-10° cooler and humidity is higher; It's 35% here today and 14% inland.Could higher humidity make wood cup?You said, "When you get the wood it dries unevenly and without any weight on it."How do I put weight on wood and still let air get at it to come to equilibrium?What happens when I give the finished box to my daughter and she takes it home to New York City?BruceT
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