Success StoryFirst Vacuum Kiln Drying System in Kentucky



First Vacuum Kiln Drying System in Kentucky

Author: Terrance Conners

Planning Unit: Forestry

Major Program: Forestry Industry Education

Outcome: Initial Outcome

A small company in Lexington, KY saws lumber from urban street trees, which it then dries and makes into specialty goods such as live-edge (i.e., bark-on) full-width slabs, shelves, etc. They also make custom furniture, specializing in wide live-edge tables. I've been working with this company since they started a few years ago, particularly with teaching and assisting them with wood drying. For the past several years they have been using a Dehumidification (DH) dry kiln, but this kiln has caused problems with warping and splitting of the thicker stock. Several companies have recently been making vacuum dry kilns available for sale. These vacuum kilns dry lumber using a different technology: ultra low atmospheric pressure combined with low heat (as compared to ambient air pressure and higher heat). Until very recently these have been both prohibitively expensive and (usually) custom built. They have therefore only been used by large companies making specialty products of high value, such as guitar bodies (Gibson Guitar Company) and baseball bat billets (Hillerich and Bradsby, dba Louisville Slugger). Vacuum drying, however, can have advantages when it's used to dry the 3" and 4" thick slabs of wood that customer want for bar tops, counter tops, table tops and so forth. When live-edge slabs of these thicknesses are sawn, they are difficult to dry using conventional means because of the thickness, the grain deviations between the center and the edges of the boards, and any knots in the piece. Vacuum drying helps the boards to dry more uniformly and with less warp. I assisted this company with their decision to purchase their first vacuum kiln, and I've continued to help them learn how to use it to dry large slabs; neither the kiln manufacturer nor the USDA Forest Products Laboratory have any information about using vacuum kilns to dry these materials so we are learning as we go. This has so far been a successful adventure, and within the last month this company has purchased and installed a second vacuum kiln to expand their production. To a limited extent, they are even doing custom drying for other companies within the state now. Even though this is a small company, they now have a unique market niche and greatly improved utilization and production potential.