Blanket Chest Design – Wood Moves.

Warped Panel

Wood is always full of surprises.  As you may recall, I had glued up some test panels to work on my raised panel design for the blanket chest.  After settling on one, I left the other one on my bench.  When I went back a couple of days later, I was greeted by the above panel.

Yes, we all know that wood moves, and yes, we all know to let wood acclimate to our shop before using it.  The thing is, this particular wood had been in the shop for almost two years!  It was some leftover knotty SPF that I hadn’t found a subsequent use for, and it had been through two full climactic cycles supported on a rack.  If any wood could be called acclimated, this was it.  Furthermore, this was a glue-up of three separate boards that were subsequently flattened.

Nevertheless, here it lay on the bench, mocking me.  As you can see from my hi-tech aluminum angle winding stick, the bow is significant.  If I were indeed planning to use it as a panel in the blanket chest, that plan would have to be abandoned.  Obviously, internal stresses were released when the panel was shaped, but I’m not yet sure what or why.  Was the fact that more wood was removed on the other side what allowed it to curve this way?  If it were simply differential drying, I would expect it to cup towards the raised-panel side, since more end grain was exposed there.  I’m tending towards the physical weakening theory, but that’s all it is – a theory.  If any of you can enlighten me, please do.

In any event, this is an unsettling reminder of the fickle nature of the material we work.  When I buy my wood next week, I need to make allowances for such possible panel disasters.  If nothing goes wrong, it never hurts to have spare poplar laying about.


One response to “Blanket Chest Design – Wood Moves.

  1. It’s because you left it on the bench, leaving one side exposed to the shop air and the other side sealed to the bench top. If you turned it over it would warp the other way. The humidity level is always changing, I always store glued up panels standing on edge, leaning against the bench or wall so air can get to all sides easily.

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