Q: I am in a tropical island and am sending you several large sized table legs. You will notice that there are some substantial splits, which seem to, more often and not, be at the ends. We see these after we unload the furniture from the container and put it in our warehouse here near the coast. Sometimes, the splits are delayed until the pieces reach our sales area. What is going on? Everyone is pointing fingers.
A: When I examined the legs, I noted that they are veneer over a composite core. It would be typical that the moisture content of this core after manufacturing would be 5 percent MC or lower, as a lot of heat is used to cure the adhesive. This heat dries out the wood in the core. If this dry core is then laminated in a dry shop, things will go well. In fact, when this material is used in a heated home, the moisture difference between the core and the surrounding air is small and so little happens. However, when these laminated pieces are sent to a humid environment, a lot more moisture increase will occur, which means that some swelling will occur. In fact, with composite wood, we often see that the first time the wood is exposed to high moisture, the swelling is much larger than expected due to springback of the wood. (The wood was pushed tightly together in manufacturing and now the pressure is relieved with excessive swelling.) Now, if the veneer or other laminated material on the surface does not swell as much, this will create tension, which will try to pull the veneer apart. When a thin piece of veneer fights against a large, solid core, the core wins.
For your special humid environment, you need to make sure that the manufacturer of the legs allows the core material to reach 10 percent MC before the legs are veneered. Is this time consuming and expensive? Yes, but it is the cure. You might be tempted to switch to a lumber core. You will have some of the same issues if the lumber is too dry at the time of laminating, but the MC difference is less and there is no springback phenomena with lumber.
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