For sterilization to occur, the internal temperature of the wood needs to be at a minimum of 133 degrees for a period of time (depending on the thickness of the boards). This kiln will allow the heat to reach 160 degrees which will be easily be hot enough for sterilization. Our objective is to lower the moisture level of the boards to between 6.5% and 7.5%.

We also have a Nyle Kiln that had been our primary drying kiln. It now has a new job but I need to back up for a bit. When we first get our boards from the sawmill, We “sticker” the boards which means that we insert small pieces of wood that measure 3/4″ x 1 1/4″ between the boards. The wood was then air dried to allow the moisture to be removed slowly. The wood will air dry more quickly when we are dealing with warm summer temperatures. In the winter will little to no heat, the wood barely gives off any moisture so it becomes a very slow drawn out experience. In the winter, 1″ walnut needs to air dry for close to five months before it was ready to go into the kiln. 2″ Walnut could take 9 months or more going from the fall to the spring. Here is where the Nyle Dehumidification Kiln will come into play. When wood comes from the sawmill, we sticker it as we normally do. Then we put the boards directly into the Nyle Kiln at 90 degrees with a light breeze. Now it will “air dry” much quicker as it thinks that it is summer time. After 1-2 weeks, it is ready to be transferred into the vacuum kiln.

The time comparision below is for starting to dry in the fall or winter months:
1″ thick wood: 3- 5 months air drying and 1-2 weeks in the DH Kiln. Now we can get the same finished product in 3-4 weeks. When dealing with 2″ slabs, the difference in time is much more pronounced.

Kiln Dried Wood – Is it Worth It? For general construction, kiln dried lumber is not necessary. In fact many people prefer to build some of their projects out of green lumber, straight off sawmill. It is easier to cut and nail, and as it dries, will shrink and form itself to the shape of what it is nailed to. So it will develop memory and be strong in the shape it is installed. Most people who have never built from green wood have never seen this effect. For example, hickory framing lumber is easy to work when it is green, but as it dries and hardens it gets to the point that nails can barely be pulled out without stripping their heads or breaking them in two.

Many people think air drying is as good as kiln dried lumber for furniture and cabinetry, but it is not. Air dried lumber can only get down to 13% – 15% moisture content in North Carolina. . This means that cabinets and furniture made from air dried wood will still be relatively wet, and will continue to dry and shrink as it is brought into a controlled environment . When in a lower moisture structure such as a house, the wood will most likely crack and warp.

Kiln drying is simply a process that allows the wood to reach extremely low moisture content in a controlled manner. As the wood gets to a low moisture content, less than 9 percent, it will lose the water in its cell walls, called Bound Moisture, contract upon itself, and become stable. Any wood will still expand and contract in a household environment, but kiln dried wood will do so at a much reduced rate