Weights bold weather-protection cover in place.

Protect stack from direct sun and rain with corrugated roofing or smlar material.

Space 4 x 4s 16-in. apart on level, wel-drained ground.

'/«•in. square stickers directly over foundation supports provide air passage between layers.

Stkkered lumber under cover. Note the lack of a ground-moisture barrier and the wfcMy spaced supports and Irregular stickers, an invitation to warping. Stickers should fine up directly over supports spaced every 16 in. along the length of the lumber.

BEST: Bufld stack entirely from one length oi lumber OR butt shorter lengths to length of stack.

LESS OGSRABLE: Begin stack with longest boards, then next longest, etc., building a trapezoidal stack. Don't just stack random lengths.

Cover supports with 6-mi polyethy lene to protect stack from ground moisture and dew.

Green wood contains a lot of water. Drying, or "seasoning," is the pixxess of removing water by allowing it to evaporate under controlled conditions. Too slow, and you risk infestations of fungi and mold. Too fast, and you end up with checks, cracks, and other drying-related defects referred to as "degrade."

The backyard lumbermaker has three practical choices when it comes to drying wood: air dry ing, kiln drying with heat and dehumidification-kiln drying.

Air Drying

A lot of woodworkers and wood dealers believe that air drying won't dry wood enough for making fine furniture. It ain't so. Not many veal's ago, virtually all fine furniture was made from air-dried lumber.

Successful air drying involves:

1. Stacking and stickering the wood outdoors, and covering the pile to keep off rain and sun.

2. Monitoring the wood's moisture content (MC) until it stops losing moisture.

3. Restickering the wood indoors in a drier environment to continue the drying process.

4. Monitoring the MC until it reaches $%, or when the wood stops losing moisture.

Air drying starts outdoors or in an unhealed building with good ventilation. Stack the lumber in a dry place that's open to breezes. Fig. 4 shows how to sticker the boards, cover the stack and keep ground moisture away.

How long should you air dry outdoors? The rule of thumb savs a year for everv inch of board thickness, but

W V w the time can reallv varv. The onlv wav to know for sure

is to monitor the moisture content of the boards. Local humidity and temperature conditions determine how dry your lumber will get outdoors. In most parts of the U.S., outdoor air drying will eventually bring the MC down to about 15% to 209r.

Measuring and monitoring moisture content is essential when drying wood outdoors, indoors or in a kiln. The simplest and most practical way to measure moisture is with a moisture meter. My advice is to get one even if vou buv all vour lumber drv, then vou know for sure how dry it is today.

Outdoor air drying is just the first step in the air-

The Deknhorst G-30 moisture meter and 26-ES side-hammer electrode can measure the moisture content deep within thick lumber. This meter has a range of 6% to 30%.

With a moisture meter, you donl have to guess when your wood b dry. The lignomat MM Ligno E/C meter has two buSt-in probes that stick in the wood to measure moisture content. Optional remote probes and cable let you take readings in the midtfle of a stack.

The Deknhorst G-30 moisture meter and 26-ES side-hammer electrode can measure the moisture content deep within thick lumber. This meter has a range of 6% to 30%.

drying process. There comes a time when the wood will stop losing moisture. At this point, it's said to have reached equilibrium moisture content (EMC). EMC means that the moisture content of the wood has stabilized with the relative humidity of the surrounding air. It won't gain or lose moisture unless the relative humidity of the air changes. The only way to dry the wood further is to move the wood to a drier environment.

Restickcr the wood indoors, ideally in a space with the same temperature and humidity conditions as the room in which the finished furniture will be used. In a heated room, vou can continue to air drv vour lumber down to the 8% MC suitable for furniture making. Fans will improve air circulation and speed things up, and your moisture meter will tell you when you're done.

Kiln Drying

Kiln drying should not be regarded as a complete wood-drying process. It's a finishing process for wood that has been air dried outdoors to 159c to 20% MC. Kiln drying is really just indoor air drying with more control over temperature, humidity and air circulation. It has the advantage of being faster than air drying.

Two different types of kiln are appropriate for small-scale lumber drying. The first type uses a heat source to warm the air, lowering the relative humidity inside the kiln. The other type lowers the relative humidity by removing moisture from the air with a dehumidifier. Both approaches require enclosing the stickered stack of wood in some kind of drying chamber—a kiln.

The kiln is really just an insulated box several feel larger all around than the stack of stickered lumber to be dried. Fig. 5 shows the details that make for an efficient kiln.

Heated kilns—Heat for a kiln can come from a solar collector, a small hot-air furnace for a mobile home or camper or a loop from a steam or hot-water heating system. Heated kilns require vents to the outside to allow warm, moist air to exit and drier air to enter. Except for solar units, which need to be placed in the sun, you can locate a heated kiln any place that's convenient, indoors or out.

You can buv solar drv-kiln kits from Wood-Mizer.

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