Burls are growths that can form on nearly any species of tree. They are the result of runaway growth by the tree cells and thought to be caused by a virus, fungus or stress on the tree . Burls are found on the trunk and limbs, or on the roots. They are prized by woodworkers and craftsmen due to the swirls, waves and patterns of the grain. These unusual characteristics require special handling.
Burl is cut from its tree trunk or limb with a margin of normal wood left on either side of the cut. A coat of wood sealer can be applied to the cut portions before leaving it to dry. Burls should be stored somewhere where they are protected from sun and rain and not touching the ground. Large burls are cut into squares or large slabs for drying. Drying may take anywhere from three to six months depending on the size and type of burl and climate conditions.
Many burls are cut into slabs once dry. These flat, thin pieces of wood can then be crafted into furniture such as end or coffee tables, or sliced even thinner and used as veneer. Slabbed burl word is found on cabinets and large pieces of furniture. Burl wood is used to cover the dashboards of expensive autos and even some musical instruments. Smaller pieces are used as inlays for jewelry boxes or knife handles.
Turning and Carving
Burls can be turned on a lathe to make bowls, lamps and other decorative items. The burl is prepared for the lathe by squaring off the back, then rounding the front so the piece is balanced. A small slice off the top will reveal the nature of the grain. Some burls will have a different pattern depending on the direction of the cut. It is possible to carve burls by hand, but the swirly grain increases the chance of gouges and other imperfections. Precise and intricate patterns can be readily cut and sanded using a rotary tool and the appropriate accessories.
An item made of burl wood can be finished in a fashion similar to any other wood. However, burls are prone to oddities like holes, bark pockets, chips and cracks. These areas can be filled in with a epoxy glue or other filler after sanding and before the final finish. The piece can then be finished with a coat of tung oil or urethane coating. Bowls or other vessels used to hold food need a finish designed for food containers.