Materials for Technical Use: Wood

Technology Department I.E.S. El Molinillo Guillena Materials for Technical Use : Wood

Wood Historical Introduction: Wood is a natural material. Wood and stone were the first materials that man used. Wood is used to light a fire, to make weapons, to build houses, etc. Some of these things are used today.

The Tree’s Trunk Wood Bark: the outer trunk´s part. It is a protector of the trunk. . Medullary Rays: they are cracks from the center outwards . Medulla: the inner trunk´s part. Heartwood: the best quality part. Sapwood: part of the trunk with life. It´s the youngest part of the wood. Its colour is light. It has a lot of sap.

Wood Obtaining Wood We can extract wood from a tree that is not too young or too old, it depends on the different species To extract wood we follow these steps: Cut down the trees Transport Clean the branches and the bark Cut the wood Dry it Distribution Life rings let us know tree´s age. The clearest rings belong to spring and the darkest ones belong to autumn.

To Cut Trees. Wood
The tools to cut trees were the axe and the hand saw.
The tools used today are the chainsaw and big machines that cut and raise the trunk quickly.
The trees are cut in the winter, because they have less sap.

Wood To Cut Trees. It is necessary to plant trees again to have wood in the future. This prevents deforestation.

Cleaning the trunks Wood Today the trunks are transported by big lorries. From the beginning the trunks were transported by the rivers ´ flow. Transportation First the trees are cut down and then the branches and the bark are cut.

To cut the wood Wood The tools to cut the wood are: traditionally circular saws and today big electrical machines or machines with engines. The trunks go to the sawmill. Here the worker marks the lines to cut the wood. This woodcutter makes planks, boards, beams, etc.

The distribution of wood Wood Drying the wood After cutting the wood, It´s necesary to dry in order to evaporate the sap and the water. The wood is stacked to allow air to flow. It is faster with hot air. The cured wood is taken to the factories.

Properties of wood Wood
The wood is hygroscopic .
The wood is a bad conductor of electricity and heat. So the wood is a good insulator.
Most wood has medium density (<1000 Kg/m3),except some like the ebony and other tropical wood.
There is very soft wood like that of poplar trees or balsa and very hard like oak or ebony.
The wood has good mechanical endurance in parallel direction to the fibres and less mechanical resistance in perpendicular direction to the fibres.
Durability : there is wood that is very resistant to fungus and parasites like walnut, mahogany…and there is other wood less durable like pines and eucalyptus.

Some interesting web links:
Wood´s Web (ES)
Wood´s Kinds (ES)
Wood in Kalipedia (ES)
Wood´s Kinds 2 (EN)
Wood´s Kinds 3 (EN)
Wood Types of wood:
The most common classification of wood is :
Soft wood : resinous and evergreen trees, they are easy to work with (pine, fir, poplar…)
Hard wood: deciduous trees like oak , walnut, ebony,…

Wood Types of wood: Exercise : make a Power Point or an Impress presentation with the different kinds of wood . You must show the main properties and applications of every one. Below you can see an example in Spanish.

Wood Wood Derivatives
Artificial Boards:
Cheaper than natural wood.
Completely flat and smooth.
Bigger size than natural wood.
Will not rot and it´s termite resistant.
Plywoods: Made with wood sheets with perpendicular fibers and are stuck together. These boards always have an uneven number of sheets.

Wood Wood Derivatives Chipboards: Made with glued and pressed wood shavings. We can paste plastic or natural wood sheets together to get a best finish quality. Fiber Boards: We can get them from wood fibers pressed together by high pressure and glued by synthetic resin (DM) or natural resin (tablex).

Wood Wood Derivatives
Paper:
Resistant
Enduring
Hygroscopic
Light
Heat insulator
Electric insulator.
Cardboard:
Obtained from a thick sheet of pulp paper.
Light and resistant.
Used in packaging.

Woodworking Wood To cut To fix To measure and to mark To smooth To drill To split To finish

Woodworking Tools:
To measure and to mark
To fix
Compass
Flexometer
Square
Vise, bar clamp and C-clamp. Wood

To cut
Hand Tools: Rip saw, backsaw and hacksaw. Power Tools: circular saw, jigsaw and table saw. Wood Woodworking : Tools

Wood Machining
Woodturning Router/Milling Machine Gouges Router bits to mill Wood Woodworking : Tools

To smooth
Rasps: with different sections. Sandpaper Electric sander Wood Woodworking : Tools

To drill
Wood Woodworking : Tools Wood auger Hand drill Drill bits Electric drill

To split
Nailing Screwing Hammer Screws Wood Woodworking: Tools Screwdrivers Powered screwdriver

To split
Gluing Paste Wood Woodworking : Tools

Finishing
Varnishing Waxing Painting Wood Woodworking : Tools

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Materials for Technical Use: Wood

by Antonio Jesús Romero on Jan 12, 2010

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