Timber preserving processes

摘要

Correct methods in the application of preservatives must be used to cater for the wide variation in timber absorption characteristics. Hot and cold bath treatment in open tanks is an immersion treatment and consists of immersing the timber in the bath, raising the temperature to about 85° for a predetermined period, then allowing the preservative to cool or transferring the timber to an adjacent cold preservative bath until cool. During this process a vacuum is formed in the cell cavities that ensures the uptake of preservative. Oil type preservatives such as creosote is used, and proper seasoning of the wood is necessary before treatment. Vacuum pressure methods of preservative impregnation are widely used commercially and have proved to be a most effective means of controlling preservative loading and depth of penetration. The most suitable method is generally determined by timber characteristics, preservative type required and the specified product end use.