Radio interview source: Lucas Peters, How-to-Editor, WOOD Magazine
Listen here to the radio story (mp3) or read below
For the do-it-yourself woodworker, a homemade solar kiln can dry lumber in as little as six weeks. The most important tip for building a kiln? The angle of your roof should be equal to the latitude of where you live.
Lucas Peters is the how-to editor for WOOD magazine. He says to take full advantage of the sun's energy, your solar kiln should be customized to your location.
"Basically that means that the angle of the roof should be equal to the latitude of where you live," he says. "So, where I live in Iowa, a roof of about 45-degrees would work best. For Texas it would be about 30-degrees, and farther north, North Dakota, maybe about 50-degrees. So with a south-facing roof and the correct angle, you're going to get the best year-round performance."
The size of the building should be in proportion to how much wood you want to dry in one batch, and the size of the roof. If you plan to dry 1,000 board feet, Peters says the roof size should be about 100-square-feet.
The roof is usually made out of corrugated fiberglass. The best materials for the building can handle heat and moisture.
"You'd want to use pressure-treated wood on all the frame members, and then exterior grade plywood for both the outside and the inside because there will obviously be a lot of moisture running through the solar kiln," says Peters. "You'll want to insulate the floor with some rigid foam, and insulate the walls and the opaque roof with some hanging blanket insulation."
Paint the interior black to capture as much of the sun's heat as possible. But to prevent it from getting too hot inside, install vents and fans to draw the air over the wood, and out the building.
Click here to download a plan for a solar kiln.