The wood (technology 2º that)
We already know that the wood is a natural matter that very has been used by the man by its properties and that all we at home have a great variety of objects that are done with wood. Wise that the age of the tree us gives it the number of growth ring. To see image of the right. In this case we have this tree has about 12 years of age. In addition it is a door to the past because based on the ring, we know if the year were warm, made much cold, etc How be known can this?
The parts of the trunk
- The main parts of the trunk are:
- , ordered to protect to the tree of the agents atmospherics. It is the external layer but and is divided in external and internal crust (Vascular cambium). In the case of the cork oak, its crust is the cork source.
- Duramen, the inner part but of the trunk. It is the hard and consistent wood. The sap no longer flows by her.
- Whiteness. It is the most recent wood in his formation around which the sap circulates most of. She is but clear and soft that they duramen
Vegetal marrow, not represented in the drawing, is located in center of the trunk. Very soft. Usually it is not used
2º Of the trunk to the board
In order to obtain wood boards a series of steps is required that are
1º Cuts. In the same forest, one cuts or mechanical mountain ranges by hand. the crusts are eliminated there and branches and 2º is transported to the sawmill One cuts to the wood of longitudinal form (direction of the trunk) with vertical mountain ranges of swing or disc mountain ranges. Now already we have the tables, ribbons, plates, etc 3º Dried. The wood has humidity and it is not good. If we make a furniture with wood just cut, over the years, the humidity disappears and so the furniture is become deformed. It is necessary to eliminate the excess of water with natural procedure or within special furnaces. With these 3 steps, already we have the ready wood for its use.
3º Properties of the wood
- We can say that the wood is:
- Easy to work. With the suitable tools, it is easy to create object useful for the man.
- Hardness. Although depends on the wood type, usually they are very hard on the basis of his weight. A wood example lasts is the oak. A soft wood, the wood of raft
- Low density. Just like before, it depends on the wood, but the majority is less dense than the water and therefore very used in boats. A 1 cubic meter (1m ³) of oak wood weighs 820 kg, while 1 m ³ of raft wood 120 kg weigh What will be better to make a boat?
- Flexible. If we doubled it in the sense of its veins, it holds much without breaking itself. It does not happen the same to against-vetoes
- Of great Aesthetic. How but we explained that with the amount of new materials it is continued using much in the home. Movable examples, grounds, etc. the ground of a house with floating platform can be shelp that also it generates a comfort sensation, when seeing
- It does not let pass as soon as the heat and the electricity. The houses in the mountain use much the wood as insulator.
Available. And we hope that it is thus by many years. For it a good policy of reforestation is necessary. The trees are much more important than we create, with some environmental functions that allow the Earth life as we understand it. Thanks to them we can eliminate great amount of emitted CO2 the atmosphere by fossil fuel combustion that brings about the heating of the planet.
- Hard wood: They come from trees with slow growth. They are denser and therefore heavier. They come to a large extent from trees of expired leaf. They are used for furniture, beams of load, and wood sizes. More faces than the soft ones, dice the slow growth of the tree.
: They are obtained from the coniferous. Light and but cheap. They last less than the hard ones and they are more prone to the attack of thermites
and other insects. The veining deficiency remains to him attractive.
We will see some sample of wood veinings in the following illustration
5º Products of the wood
Aside from the board or ready coming from the sawmill, we have others by its importance we happened to detail.
Agglomerate is obtained with the waste of the wood (branches, pieces without value, etc) that once crushed, it is mixed with tails later to put under them compression and to form the board. Can be added to a laminated wood or plastic layer of to improve finished his.
Plywood Is the union of several laminae (a drawee 90º respect the other) united with tail. The result is a quite cheap board with very good benefits as far as mechanical resistance.
Fiber boards and moldings. Are obtained soon with the resin and wood particle mixture of and pressing to form the board. Example, the DM. As in the case of the agglomerate, the humidity affects much to him.
Alistonados boards. Ribbons are obtained when uniting some with others by means of tails. Boards of some are obtained of this form great dimensions for the use in the manufacture of houses, panels, elements for the construction, etc
Paper. Material very used. Summarizing the process, it is obtained with the wood crushed in fine particles and mixed with chemical agents to form the pulp. To the pulp one adds blanqueantes to him and with the final step of the pressing, the paper roll is obtained. Blanqueates can contain chlorine which does of the somewhat polluting process. The modern processes it usually replace by active Oxygen, that does not harm to the environment.
6º Tools for the wood
- According to its application, we have
- In order To hold - > the vise and the sergeant or cat
- In order to mark and to draw up - > For it is used the carpenter pencil, the rule, the square, the compass and flexómetro
- In order to saw - > the frequent tools but are the mountain range manual (hand saw, fretsaw. ) or the power saws as the mountain range of disc or mountain range to pierce
- To perforate and to drill - > For the first task is used the drill and for the second drill
Finished. In order to eliminate small pieces of material we used you file them (if it is of great tooth is called escorfina) and to give a smooth aspect to the wood, the sandpapers
Once we have the finished piece or, to unite it to another piece the wood screw can be used (are them with different forms) or ears. The ears are made normally of wood and enter the two pieces. When entering the orifices of the two pieces it creates a union of great resistance. He is advisable to add white tail in both ends of the ear. Also we can use a great variety of nails and screws (some of them requires previous drilling)
Other types of union are machiembrada and the Tail of Milan
Machiembrada wood union
Tail of Milan (very used in drawers)
8º Dyes, varnishes and finished others
We can use several substances to improve the aspect at the same time as it protects it. First of them it can be a painting, but it has the disadvantage that annuls the vein and the wood does not transpire
2º With the Varnish, we protect to him of outer agents, although he is impermeable and therefore the wood does not transpire
3º Lasur, seemed to the varnish, but in this case the wood transpires (open pore) and avoids that fungi in the interior are created. Usually one adds other substances that it protects to the wood of the ultraviolet radiation, agents atmospherics, insects, fungi, etc to him
4º oil and Beeswax of theca is other products used in creating certain style to the woodDictionary
Thermite. Uff, as bichejo falls to you at home this. So simple because you remain without furniture. In only weeks, they are able to devour the furniture of a house. They are limited to devour the wood, and clear, if but it is brandished, easier that they eat it. The problem is that the bushes where you see them but the termitero are to meters under earth and four streets further on.Drill
: It is used to make small orifices with the idea facilitate twists together of a screw. escornina