WOOD AND ITS DERIVATES

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1 WOOD AND ITS DERIVATES 1º ESO BILINGUAL TECNOLOGIES IES MIGUEL ESPINOSA 2012/2013 WOOD AND ITS DERIVATES WOOD CLASSIFICATION EQUIPMENT, TOOLS AND MACHINES Properties of wood How to process wood Preparing wood for use Hardwood Softwood Wood derivates -Measure, mark, draw and secure -Cutting and sawing -Drilling -Carving or levelling -Planing or sanding -Joining pieces -Finishes 1

2 1.WOOD Raw vegetable material. Itcomes fromthetrunkof treesand bushes. (and branches) It is composed of: - Cellulose fibres(like all vegetal matter) - Lignin(which makes it rigid and hard) Thepartsof a treetrunkyouseewhenyoumakea horizontal cut are: - Bark(exterior layer): protects the plant - Cambium: (a thin transparent layer) - Sapwood(recent growth): not very strong, used for woodwork that need soft wood - Heartwood(thestrongpartthatkeepsthetrunkvertical): hardand dry, extracted and processed for all types of woodworking - Pith(the centre of the trunk): very weak, not generally used bark cambium pith sapwood heartwood 2

3 1.1. Properties of wood Factorsthatinfluencethepropertiesof wood: 1. Typeof tree 2. Environment 3. Soil 4. Ageof thetree 5. Composition of the wood 3

Physical properties Properties Hardness Density Electrical insulation Characteristics Wood is hard, but can be

Dry wood provides good electrical insulation.

Porosity Mechanical resistance Wood can absorb or emit liquids or gases because it has tiny holes, called pores.

Colour and grain Wood has esthetic qualities: a variety of colours and grains.

4 Physical properties Properties Hardness Density Electrical insulation Characteristics Wood is hard, but can be penetrated by objects such as screws or nails. Wood is less dense than water, so it floats. Dry wood provides good electrical insulation. Thermal insulation Wood provides good thermal insulation, but it burns easily. Porosity Mechanical resistance Wood can absorb or emit liquids or gases because it has tiny holes, called pores. Wood has good mechanical resistance against forces of traction (tensible), compression or bending (flexural). Colour and grain Wood has esthetic qualities: a variety of colours and grains. Ecological properties Wood is a renewable material, but deforestation causes serious damage to the balance of our ecosystem. Wood is biodegradable. It descomposes as time passes. Wood is recyclable. We can do other things from it, as prefabricated boards, paper or cardboard. 4

5 1.2. How to process wood The process starts with the extraction of the log(raw material) from the forest and ends with the production of planks(used to make objects). 1. Cutting and pruning. The trees are cut down with chainsaws and the branches are then cut off. 2. Transport The logs are transported by road, rail or water to their destination. 3. Removing the bark At the sawmill. A chain of rollers with metal teeth turns and removes the bark. Log: tree trunk that has been cut down for processing or burning. Plank: wood cut into a flat board which can be of varying size and thickness. To prune: process of removing branches from a tree. 4. Sawing The logs are cut into planks or boards that cut parallel to the axis of the log. 5. Drying Under pressure so that it doesn t warp. Dry wood last longer and is lighter. 6. Planing The wood is planed to make the wood smooth and evenly flat and give it a good finish. Warp: be deformed because of a process of change. 5

1.3. Preparing wood for use Afterremovingthebark, thelogsare cuttomakeplanksand boards of different thicknesses. Washing and drying are important processes to treat the wood.

6 1.3. Preparing wood for use Afterremovingthebark, thelogsare cuttomakeplanksand boards of different thicknesses. Washing and drying are important processes to treat the wood. Thewaterand thesapare removed and thewoodis protected from attacks from insects, fungus, etc. Cutting: Wecutondifferentways, dependingonwhatwewanttouse it forand howwewantittolook. Ways of cutting and sawing wood: Washing. The wood is put in water for a long time to extract (remove, take away, take out from) different fluids (tannin used for making leather). Drying: The water in the wood is reduced through evaporation. - Methods of drying wood: a) Natural drying. The planks are put in piles, out of the rain and direct sun, with spaces between them so that the air can circulate. This is a slow process. b) Artificial drying. The wood is dried in big rooms (dryers) with hot, dry air. This system is quicker and more efficient. c) Mixed drying. This is a combination of the two methods. First, natural drying is used until humidity of the wood reaches about 20%, then artificial drying is used. 6

taza Crook: acodado Bow: arqueado Twist: retorcido Split:

7 Warping: These are the ways in which wood can warp: - Cup - Crook - Bow - Twist - Split Warp: combar Cup: en forma de taza Crook: acodado Bow: arqueado Twist: retorcido Split: agrietado Different cuts of a wood from log: Log: tronco, leño. 7

Resin: a stick substance found inside wood. - They can be in many different colours, are compact and are resistant.

8 Wood is classified as hardwood and softwood depending on the tree it comes from. HARDWOOD: - Deciduous trees. Deciduous: trees that lose their leaves in winter. - They grow slowly and have thick trunks. (tronco grueso) - They contain little resin. Resin: a stick substance found inside wood. - They can be in many different colours, are compact and are resistant. Their most common uses for woodworking: 1. Beech: (haya) Characteristics: Heavy and easy to work with. Not very resistant to damp. Damp: a slightly wet or humit condition. Furnitures, floors, chair frames and legs, handles, toys, matches, rods. 8

9 2. Oak: (roble) Characteristics: Heavy, very hard and resistant. Solid furnitures, doors, windows, wooden floors, parquet, boats, barrels. 3. Cherry: Characteristics: Not very heavy. Furniture, wall and furniture panelling, wooden floors, scientific and musical instruments (e.g. oboes). 9

10 4. Mahogany: (caoba) Characteristics: Very heavy and long-lasting. Joinery, luxury furniture, hand-carved objects, musical instruments (e.g. guitars). SOFTWOOD: - Conifers(trees with needle-shaped leaves). Needle: aguja. - Theygrowquicklyand haveclearannualrings. - The wood is resinous and usually ligth-coloured. - It slight and easytoworkbecauseit slessresistant. 10

Some of its most common uses for woodworking are: 1.

White fir (abeto blanco) Characteristics: Elastic, non resinous

11 Some of its most common uses for woodworking are: 1. Pine Characteristics: Resistant to changes in temperatures. Easy to work with and resinous. Furniture, boats, electricity posts, floors. 2. White fir (abeto blanco) Characteristics: Elastic, non resinous and not very resistant to bad weather because it is attacked by fungus. Building, boats, simple furniture, carpentery, boxes, paper. 11

12 3. Red fir (abeto rojo) Characteristics: Light and easy to work with. Fencing, boxes, wood panelling. Fencing: cercados 4. White poplar (álamo blanco) Characteristics: Light, soft and not very resistant. Furniture frames, plywood, paper. Frames: marcos. Plywood: madera contrachapada. 12

13 2. DERIVATES Do not come directly from the logs that are cut, but from wood sheets, fibres or chipsthat are compressed and glued together. Sheets: thin, flat piece of material. Chip: little piece or fragment of material. PREFABRICATED WOOD PRODUCTS: Advantages: Easy to work with. A lot of different sizes and finishes. They are not attacked by parasites. Made from the leaveovers of wood cutting, so are more ecological and cheaper. Leaveovers: what remains after the main part has been used. 2. DERIVATES The most important types: Plywood: Thin sheets of wood glued together and compressed. The fibres in one sheet are at 90º angle to the fibres in the next sheet. An odd number of sheets are glued together so that the top and the bottom have the same finish. Very sensitive to humidity and temperature changes. They can warp and increase in thickness. Use: Joinery, doors, packing, agricultural construction, boats. 13

14 2. DERIVATES Chipboard Made with wood chips glued together (90% chips and 10% glue) and compressed. To improve strength and appearance they are covered with a natural sheet of wood or with plastic (melanine). Fragile and not easily deformed, although occasionally they can bendand increase in volume because some of their components are affected by changes in humidity and temperature. Use: Furnishings, doors, ceiling panels, dividing panels, insulation panels for prefabricated buildings. bend. To become curved or form a curve. 2. DERIVATES Fibreboard The fibres come from milling the wood chips. This gives tiny wood threads which are compressed and glued together to make a conglomerate. The fibre planks have different grades of density (medium density, MD, and low density, LD). Compact, flexible and easy to work with. Exterior covering (because it has a smooth surface), furniture, cabinets, shelving, doors. 14

15 2. DERIVATES Hardboard Made from wood left over from the mill, unused pieces of wood. Compact, flexible and easy to work with. It is compressed together with glue to make lining for cupboards. 2. DERIVATES Cellulose materials Made from the cellulose found in wood. The most important product made from them is paper. - Making paper: Wood is pulpedand mixed with water and chemical products to make cellulose paste. Pulped: cut into small pieces and mix with water. This is compressed and rolled out by a machine until it become a sheet of paper. Rolled out: flattened out with a cylindrical tube or roller. 15

16 2. DERIVATES Other cellulose materials: - Cardboardismadein twoways: 1. By hardeninga thicksheetof paperpaste. Harden: make hard 2. Bystickingtogetherseveralsheetsof papertomakea thicker sheet. In a similar waywecan make: - Tissue paper(very thin sheets of paper). - Card(more resistant than paper, but more flexible than cardboard). 16

UNIDAD 5. LA MADERA. UNIT 5. WOOD

UNIDAD 5. LA MADERA. UNIT 5. WOOD WHAT IS WOOD? -RAW MATERIAL -MATERIAL -TECHNOLOGY PRODUCT THE ORIGIN OF WOOD IS. - ANIMAL ORIGIN -VEGETABLE ORIGIN -MINERAL ORIGIN 1 WHAT IS WOOD MADE OF? Wood is made