Tropical Wood Moisture Content?

Tropical Wood Moisture Content?

I am currently working with tropical wood like mahogany, walnut, etc. My problem has been, after drying the wood to between 15 percent to 17 percent moisture content, I sometimes run into problems with the panels separating from the stile and rails. After either spray painting or varnishing the door, I tend to experience cracks at the glued joints after a period. I desperately need advice on how to PREVENT and also the BEST way to FIX this. – Sam W.

Tim Inman: Fifteen to seventeen percent moisture is WET for cabinet work. While it is considered OK for firewood, it isn’t dry enough for good cabinet lumber. Usually an Equilibrium Moisture Content (EMC) of 6 to 8 per cent is the goal for furniture lumber. The EMC possible for your wood depends upon your relative humidity in the air where you are, which varies from one season to the next, but the drier, the better. As you know, sadly, from your experience, at 15 percent, there is still enough moisture left in the wood to allow more physical shrink when that last few percentage points of water evaporates from the wood.

Chris Marshall: Some shop lessons are hard learned, Sam. Tim has already shared the bad news with you here. You need to start with drier wood. What you’re using at that moisture content is not a long way off from construction-grade 2x4s. Drier lumber will behave better, I promise.

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