Advantages of Timber

1.Timber can be easily worked with tools of any size and can take a good polish.
2.It is comparatively stronger than any other materials in proportion to weight. That is other materials of such light weight as timber are not stronger than timber.
3.It is economic in the sense that any small piece of timber can be utilized.
4.Its use for making furniture, sports goods and decorative articles of artistic design are accepted universally without doubt.
5.Its low thermal conductivity, high resistance(electricity) and sound proofing property make it as an important building material.
6.timber structures are comparatively durable if properly treated and carefully protected from direct contact with weather and alternate change in wetting and drying.
7.Various types of timber products such as plywood, laminated board. hard board etc are nowadays used because of low weight and beauty.
8.It can be used both load bearing and non-load bearing members in structures and structural connections.
9.Its another importance is great resale value. The discard timber can be used as fuel.Even saw dust can be used by reconstructing partex board, hard boards, laminated boards etc.

Definition of Timber

Any wood which is used in engineering works is termed as timber.Although some of its usages are given up to steel, concrete and other products its usages in construction and other commercial purposes are still of great importance.

Estimation of Wastage if Timber

In conversion of timber there is a great wastage.When a log is sawn only 50 to 65 percent can be useful other is waste.Following are the approximate estimation of wastage

Side slabs and trimmings--18%
Saw dust--12%
Bark--5%
Loss of moisture--5%

Pressure Process of Applying Preservative

Pressure process is one of the most efficient process in applying preservative. It is of two kinds.

1.Full cell process:In this process cells of wood tissues are desired to practically completely filled with preservative.Woods are loaded on a special kind of trolly and then put in autoclave machine.The vacuum is applied inside the autoclave to remove air from wood as much as possible.Then heated(generally 210 degree Fahrenheit) preservative is pumped in the autoclave with 125 to 200 psi pressure.


2.Empty cell process:In this process preservative forms merely a thin layer on wood cells.All the process is same with full cell process, except that before applying preservative 50 to 75 psi pressure is created to fill wood cells with air and then preservatives are added with about 200 psi pressure.

Differences Between Sapwood and Heartwood

       Sapwood                                                Heartwood
1.It is the living element of           1.It is the dead element of tree.
tree.
2.It is comparatively weak.           2.It is comparatively strong.
3.It is more in young trees.          3.It is more in old trees.
4.Contains higher moisture.        4.Contains less moisture.
5.Lighter in color                         5.Darker in color.
6.Has weaker cell wall.                6.Has weaker cell wall.
7.Attracts fungus and insects      7.Does not attract fungus and insects.

The Essential Properties of Preservatives of Wood

1.It should be safe in handling and use.
2.Non injurious to wood tissues and do not react with them.
3.Should not get washed away and permanently preserve.
4.Should be such that decorative and ornamental paints could be applied on wood.
5.Should be non flamable.
6.Penetrate thorough timber.

Market Forms of Timber

The followings are the various types of market forms of timber.
1.Log     2.Lumber     3.Bilk     4.Deal     5.Batten     6.Plank     7.Board     8.Scantline     9.Pole

Conversion of Timber

The preparation of timber from felled tree by cutting off branches, removing bark., cutting and sawing to convert it to marketable form is termed as conversion of timber.

Ply wood

Plywood consists of number of thin sheets of wood(veneer) which are pressed and bonded together by some bonding materials like glue or synthetic adhesive under temperature of 350 degree Fahrenheit to 500 degree Fahrenheit.The grains of each sheet are bonded right angles to each other to uniform strength in both direction and reduce shrinkage.Plywood is relatively lighter then other plank of same strength. Sometimes plywood is covered with plastic sheet for attractive appearance, zero water absorbance, reduction of decay etc. Plywood is specially used where some amount of bending is necessary. Generally not less then three sheets of woods are used for plywood.

Veneers

Veneers are thin layers of wood of 1/16 to 1/ 4 inches..It is used when lightness, stiffness, durability, no-shrinkability, non-splitting and decorative properties are desired, Veneers are generally obtained from those woods which have well shaped grans and pleasing appearance. Veneers are used in mainly manufacturing plywood, batten boards, decorative facings and laminating boards.