Timber

Processing of timber

The age of good trees for felling varies from 50 to 100 years.

Seasoningof Timber

• The water in the form of sap and moisture is to removed before the timber can be used.

• The remaining moisture is uniformly distributed throughtout the mass.

• By the process of seasoning, the excess water is extracted such that it corresponds to the required moisture content.

Methods of Seasoning

The methods of seasoning can be broadly divided into two categories:

1. Natural seasoning2. Artificial seasoning

Natural Seasoning• In this method, the

seasoning is carried out by natural air and hence it is sometimes referred to as Air Seasoning.

• The timber pieces are stacked either horizontally or vertically.

• This method of seasoning is cheap and simple.

• It usually takes about 2 to 4 years to make timber fit for the work of carpenter.

Artificial Seasoning

The various methods of artificial seasoning are as follows:

a) Boilingb) Chemical seasoningc) Electical seasoningd) Kiln seasoninge) Water seasoning

Seasoning is carried by sending steam inside a chamber.

No. Item Natural Seasoning Artificial Seasoning

1 Moisture content It is difficult to reduce the moisture content below 15 to 18%

The moisture content can be reduced to any desired level.

2 Nature It is simple and economical.

It is expensive and quite technical.

3 Quality of timber The air seasoned timber is more liable to the attacks of insects and fungi.

The kiln seasoned timber is less liable to the attacks of insects and fungi.

4 Space It requires more space for stacking.

It requires less space for stacking.

5 Speed It is a slow process. It is a quick process.

6 Strength It gives stronger timber. It gives a little weaker timber.

Industrial TimberThe timber which is prepared scientifically in a factory is termed as the

industrial timber. The following are the varieties of industrial timber:1. Veneers2. Plywoods3. Fireboards4. Impreg timbers5. Compreg timbers6. Block board and lamin board7. Glulam8. Flushdoor shutters9. Particle board or chip board10. Hardboard

Veneers

These are thin sheets or slices of wood of superior quality.

• The thickness of veneers varies from 0.40mm to 6 mm or more.

• They are obtained by rotating a log of wood against a sharp knife of rotary cutter or saw.

The veneers after being removed are dried in kilns to remove moisture.

•The edges of the veneers are joined and sheets of decorative designs are prepared.•The process of preparing a sheet of veneers is known as the veneering.•The veneers are used to produce plywoods,battenboards and laminboards.•The veneers may be fixed on corners or bent portions.

The veneers may be glued with suitable adhesives on the surface of inferior wood.The appearance of inferior wood is then considerably improved.