Lumber Goes Thermal
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Bingaman Lumber uses Westwood’s kiln (above) to thermally treat poplar, maple and pine.

Thermally treated wood is gaining visibility in the U.S. market. More widely known in Europe (it’s used in sauna and steam bath build-outs), the process employs specialized high-temperature kilns and steam to treat either hardwoods or softwoods, making them insect- and water-resistant and weatherproof without chemicals. In the kiln, wood darkens as the process removes organics that can contribute to decay. Some users say this permits certain lighter wood colors to stand in for darker and more expensive species.

 
Thermally treated wood offerings include
(from top) Keystone Wood Specialties ash,
poplar and red oak; Bingaman’s pine (before
and after treatment); Lewis Lumber mouldings;
Jartek wood samples.


Unlike pressure-treated woods, the thermal modification process creates the impervious wood without impregnating it with chemical preservatives.

Several suppliers at the 2010 International Woodworking Fair will be exhibiting products related to thermally treated wood. Jartek (Booth #6056) offers its ThermoWood kiln to thermally modify woods at high temperatures (approximately 200 C). The kiln is designed to resist corrosive acids and other chemicals extracted from wood, as well as the stresses of large-scale temperature changes during the process.

Thermal modification can be started from pre-dried or green timber, says Jartek. A software controller enables customized processes to tailor “cooking” recipes for different species.

Westwood (Booth #7036) says woods treated in its kiln process (designed specifically for hardwoods) can be used in extreme conditions: outdoor rooms, boat interiors, heavily trafficked wooden staircases, saunas, even sinks. The intense heat used in the kiln converts the molecular structure of the wood fibers, says Westwood president Igor Dachenko. This can affect its strength, which is a consideration for some uses.

Bingaman Lumber (Booth #4546), says woods it converts in its Westwood kiln attain 25-year outdoor durability. Treated poplar, ash, red oak and soft maple will resist decay and insects. Bingaman recommends Thermo-treated hardwood for decks, siding, stairs, moldings, parquet, cabinets, furniture, wall panels, floor, windows and doors. Lewis Lumber (Booth #4834) and Keystone Wood Specialties (Booth #4244) also sell the thermally treated wood or components.

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