MOTHER’S Solar Wood-Drying Kiln: Part Two

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Photo by MOTHER EARTH NEWS Staff
Unusually wet summer weather inhibited the performance of the solar wood-drying kiln.

Those of you who are following our solar wood-drying kiln project (A Look at MOTHERs Solar Wood-Drying Kiln: Part One) are probably looking forward to further data concerning the success of our experiment, which entails using the sun’s energy to reduce moisture levels in freshly harvested lumber to a point of equilibrium with its environment.

Well, in this second installment, we’re prepared to offer reliable figures. However, we still can’t promise that our kiln design will actually achieve its intended goal, simply because our two test batches (500 board feet each of oak and yellow pine) haven’t yet completely given up their available moisture.

As you might imagine, the economic savings realized in solar drying is offset to some degree by the sheer unpredictability of Mother Nature; if there’s less sunlight available over a period than was anticipated, the only option is to wait it out. Then again, as we explained last time, seasoning wood isn’t all that simple a task because the rate of moisture removal — be it fast or slow — directly affects the quality and serviceability of the finished product. In short, since we know that at this writing each of our sample charges should still give up about 8 percent more moisture (based on ambient temperature, relative humidity, and particular species), it’s simply too early to determine with any accuracy whether or not our boards will have a successful seasoning.

Rain, Rain, Go Away

Traditionally, the Blue Ridge Mountains of western North Carolina (where our kiln is located) experience a moderate climate. Cloud cover is the exception rather than the rule, but last summer our region endured an unusually stubborn rainy spell, which happened to coincide with our first instrumentated test, initiated in mid-June.

  • Published on Nov 1, 1984
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