Learn about the prerequisites for the best slab drying results
The process of drying live edge slabs can take over two years. Despite the eagerness to use freshly cut green slabs for a project, it's essential to allow them to air-dry adequately before they go into the kiln. As a rule of thumb, it's recommended to air dry live edge slabs for one year per inch of thickness before kiln drying. The desired moisture level for kiln drying is up to 20%, and upon removal from the kiln, the ideal moisture level depends on the intended environment. We typically aim for 12% or less for outdoor use and for indoor use, 8% moisture content is desired.
Using a green slab for furniture without proper drying may initially look fine, but over time, issues such as cracking, warping, and failure of joints may occur. These problems could arise shortly after placing the piece in a home or even up to a year later. To ensure that live edge furniture ages as intended, it is crucial to follow the proper drying process.
After cutting, it is essential to place the slabs on stickers to allow for good air circulation. This practice prevents rapid drying, which can lead to cracking and warping. Additionally, the stickers evenly support the weight of the slabs and help maintain their straightness.
A moisture meter is used to test the slabs' moisture level, with a target of 20% -25%, indicates they are ready for kiln drying. The duration of air drying varies depending on the thickness of the slab, average ambient temperature and humidity, and how well the space is ventilated.
Once air-dried, the slabs should be placed in a kiln for approximately 4-12 weeks. It is advisable to coordinate with Kitsap Dry Kiln well in advance, due to potential backlogs.
Kilns control air circulation, humidity, and temperature to reduce the moisture in wood. There are two common types of kilns; conventional and dehumidification. Conventional kilns use high heat generated from steam to lower the kiln box humidity and dehumidification kilns pull moisture from air mechanically at moderate-to-low temperatures.
Proper kiln drying requires professional equipment and expertise to ensure the quality of the lumber and slabs. Experience allows us to apply the best practices to ensure the best possible outcome of drying your slabs. Keep in mind that there are many defects that start in the tree that affects the quality of the product which show themselves during drying. See the Forest Products Laboratory, “Kiln Drying Operator’s Manual”, or Kitsap Dry Kiln’s “Lumber Drying Defects” (below) for more information.