Civil Engineering Today

  WOOD PRODUCTS The common industrial timber products are: 1. VENEERS - Timber veneer is a decorative building material comprising thin slices of timber glued onto wooden board , particle board or fibreboard .  It has been favoured by builders and designers since ancient times as the finest and most efficient use of the valuable timbers.  Veneer is produced as a thin layer of timber that is uniform in thickness.  The veneer is normally between 0.5 and 0.85mm thick .  Timber veneer is from a natural and renewable resource competing with non-renewable commodities like steel, aluminum and plastics.  The surface coverage of veneer is approximately forty times more than 25mm timber, which makes it the most economical way of utilizing precious wood.  One cubic metre of log produces around 1,000 square metres of real timber in veneer form.  No other form of wood working material results in such an efficient use with minimal wastage.   ...

    SEASONING OF TIMBER Seasoning is the process of reducing moisture content in a freshly cut tree to the desired level. In other words, Reduction of moisture content along with improving some qualities before the use of woods is called seasoning of timber. By seasoning, generally, the moisture is reduced to about 15% where new cut woods bear about 50%. Timber is wood that is used for building houses and making furniture. Basically, timbers are used for structural purposes. Those woods, which are adapted for building purpose, are timber. When the trees are cut down, it will be having approximately 50% of moisture content. Timber cannot be used immediately after the cutting of trees because of the tree contains an uneven sap. If the excess moisture is present within the timber will shrink excessively.It will even have a tendency to decay so, there is the only seasoning of timber is one of the solutions. The 100% amount of the moisture cannot be removed from the Tree...

  Defects in timber   Defect occurring in timber are grouped into the following five categories: ·  Defects due to conversion ·  Defects due to fungi ·  Detects due to insects. ·  Defects due to natural forces. ·  Defects due to seasoning.   1. Defects due to Conversion - During the process of converting Timber to the commercial form, the following defects may occur: a. Chip Mark: This defect is indicated by the marks or signs placed by chips on the finished surface of timber. b. Diagonal Grain: Formed due to improper sawing of Timber. It is indicated by diagonal mark on straight grained surface of Timber. c. Torn Grain: In the conversion, many tools are used. If any of the tools or any other heavy things are dropped accidentally on the finished surface of timber it will cause small depression, which is called torn grain. OR    -   Small depression formed due to falling of a tree. d. Wane: This def...