Round logs baked square

 
Last Updated: Saturday 04 July 2015

-- ROUND logs can be transformed into square ones without using a saw. The process yields wood that is stronger, denser and less liable to split and warp (New Scientist, Vol. 135, No. 1828).

The method, evolved by Japanese scientist Yoshinori Kobayashi, involves baking the logs to around 1000 C in a specially designed microwave oven. The baked logs are then pliable enough to be compressed into squares using pressure as low as 10 kg/cm sq. The logs retain their shape on cooling. Prior to Kobayashi's technique, about 50 per cent of timber was lost in the saw mill. This technique can also straighten out crooked logs, which would otherwise be discarded.

As the logs are compressed, water and steam is squeezed from them and the logs become harder, denser and, hence, superior. Five litres of water is squeezed out of a meter-long, typical cedar log, giving it the strength of the more expensive Japanese cypress.

Given its commercial promise, a number of private companies want to use the process, but Kobayashi says local authorities in Nara prefecture are holding back the license as they want local companies to use it first.

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