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Wood

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Rural Technology

Main function of trunk is to support the tree. Nature makes the trunk stronger by connecting cellulose fibers using lignin. In this way flexible but strong fibers are connected to each other to bring stiffness. Man has made, use of this structure in imaginative way for their benefit. Wood is primarily used as a fuel. But it is also used as a construction material for making houses, tools, weapons, furniture, packaging, artworks, and paper.

Advantages of Wood

In construction work wood is one of the most important materials-Advantages of wood is as follows: 1. Wood never catches rust or never rots. 2. As compared to its weight, wood is strong and stiff. 3. Wood is bad conductor of heat. Therefore, it never becomes more hot or cold. 4. Different attractive and beautiful articles can be made from the wood.5. We can give desired shapes to wood easily. 6. By doing plantation we can get required quantity of wood.

Disadvantages:

Disadvantages of wood are: 1. Depending on size of the wood, it has to be used by joining joints. 2. The price increases as the size increases. 3. As it is natural product, there is wide variety of wood. 4. It is easily inflammable. 5. Insects and termite can infect the Wood. 6. With variation in humidity in atmosphere, wood gets wet, shrinks and develops cracks.

Type of wood

Following are the characteristics of commonly found wood shown in table no.1. Seasoning The fresh wood contains lot of water, when it is just cut out from the trees. Its strength is less and chances of forming fungus on it are more. Therefore, wood needs to be dried. Sometimes its corner portion dries faster than the inner core which causes it to shrinks from one side and may develop cracks. Therefore, it is necessary to dry it slowly. This drying process is called as ‘Seasoning’. Commonly, wood is cut into small planks and they are kept for drying in covered place with sufficient space between the planks and proper air circulation. Drying under direct sun light is avoided. Chemical process is done on the wood before drying to avoid fungal infection. Prevention of termite If wood is stored in close or humid place, the ant like insects eat it. These insects create their path like a tunnel using soil. Such wood is said to be infected by white ants or termites. Termite reduces strength of wood. As a preventive measure chemical treatment using asphalt, chuna(limestone) is painted on the wood.

Plywood

Plywood is a board made from thin sheets of wood. Wood is cut across the grain as shown in fig 4.1. Plywood is made by laying up multiple layers of sliced or peeled veneer called plies. The layers are glued together, each with its grain at right angles to adjacent layers for greater strength. The plies are bonded under heat and pressure with strong adhesives, usually phenol formaldehyde resin. Some types of plywood are even resistant to hot water.

Intext Questions

Fill in the blanks: 1. Wood is conductor of heat. 2. Drying process of wood is called . 3. To protect wood from termites’ is painted on the wood.

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Rural Technology