How to Kiln Dry Wood
You need to dry wood to perfection to improve its strength and to prevent mold attacks due to trapped moisture inside the wood grain. And when it comes to drying or seasoning wood, there are two ways to do it.
You can use the air-drying technique that lets wood pieces dry with the aid of sunshine and air. Wood is stacked and left to the elements and this can take months to completely dry. But for faster wood drying, most woodworkers rely on kilns.
Kilns are similar to conventional ovens. These dry wood using hot air. Most kilns are wood-fired and are so effective that it can season wood to perfection in just a few weeks.
Kiln drying basics
You may either have a kiln at home or you can have your wood dried from a local sawmill with a kiln. But if you plan to start drying more wood to be used as construction material or for firewood soon then it would be a good idea to construct your own kiln at your property.
Things you will need
- Wood to be dried
- Moisture meter
1) Use a moisture meter to find out the moisture content of your wood
This will help establish a baseline value. A moisture meter is the most accurate test for determining a wood’s moisture content. It is a small handheld tool with two metal probes that are applied to wood. These probes read the moisture content of the surface as well as the internal part of the wood. The reading is expressed as the percentage of moisture according to the wood’s volume or weight.
Use the moisture meter according to the manufacturer’s directions. The normal moisture content for wood used in woodworking projects is 6 or 7 percent. If you get a higher reading, it means that the wood needs to be dried and it is not ready to be used.
2) Use stickers to dry the wood
“Stickers” are simply 1″ x 2″ (25 x 50 mm) pieces of lumber that are used to provide airflow between the boards you are drying. Lay each sticker about 16 inches (40 cm) apart and line them up parallel to each other. You’ll need enough stickers to support the entire length of the boards you are drying.
Stack the first layer of boards.
Carefully set the first layer of wooden boards on top of the stickers, running them perpendicular to the stickers. Leave an inch or so of space between each board to allow for increased airflow.
3) Preparing the kiln
Allow the kiln to reach the ideal maximum temperature to dry wood. Close the kiln door to keep the temperature inside the chamber. Use a thermometer to find out the temperature inside the chamber.
Once the kiln has reached the ideal temperature, place the wood one by one inside the kiln. If you have metal grates inside the kiln then you can arrange wood in such a way that no part of each wood touches the other pieces. This will greatly improve drying and will ensure that all the surfaces of the wood pieces are exposed to the hot air.
Take care that your kiln does not run out of fuel so that it can maintain the temperature inside the chamber. Most kilns are wood-fired so be ready with a large stack of wood nearby just in case you need to refuel.
4) Test the moisture level of your wood
Take two pieces of wood from the kiln and test it. If the results show high moisture levels, return the pieces inside the kiln and dry some more.
5) Post kiln care
Once the wood is ready, remove it from the kiln and stack these in a neat pile. Use stickers (small pieces of wood) when you stack your newly dried wood. Place a row of stickers on top of the boards, lining these directly with the previous set of stickers.
Continue alternating stickers and boards until you’ve stacked every piece of wood. You may store the wood inside your garage or tool shed but if you must let these remain outdoors, cover the drying wood with a tarp or other overhanging fabric.
Kiln drying will be able to dry wood fast and in a more efficient manner. It can reduce drying times and can make wood ready for use in just weeks compared to months when you air dry. It would also be good to have a moisture meter whether you are air drying or kiln drying wood.