1 ESO technology wood Unit

Unit 3. The materials. Wood

What are we going to see in this unit? 3.1 Materials and their classifications 3.2 Wood properties and constitution 3.3 Wood extraction and processing 3.4 Wood classification 3.5 Wood derivatives 3.6 Wood tools

3.1 Materials and its classification

Are these objects made with the suitable materials?

Wheel Book light bulb hammer

Material

3.1 Materials and their classificationsEach material has special properties that

make it suitable for a particular instrument, tool, etc.

Therefore, when we make an object we have to select the appropriate material.

We can classify materials into two groups:Natural materials: they are obtained directly from

the environment.

Synthetic materials: we obtain them through a manmade process.

Cotton

Wood

Plastic

Concrete

3.1 Materials and their classifications

We can classify materials according to their origin:

Let’s start learning about wood!

WoodMetalPlastic

Stone materialCeramic and glassTextile material

3.1 Materials and their classifications

3.2 Wood properties and constitution

Wood is a raw material formed by cellulose and lignin.

Cellulose: it is a natural fiber that supports a tree. It’s like its skeleton.

3.2 Wood properties and constitution

Lignin: it makes wood harder and more rigid, it’s like glue that holds the cellulose together.

3.2 Wood properties and constitution

Medulla: soft central part

Heartwood: dry hard wood

Sapwood: The sapwood carries water from the roots up to the leaves.

The trunk has different parts with different properties

3.2 Wood properties and constitution

Cambium: Thin transparent layer that develops new wood.

Bark: This last layer protects the tree from insects and disease.

3.2 Wood properties and constitution

Properties:There are many types of wood, and each

one has a special property:Density: is the relation between mass and

volume

3.2 Wood properties and constitution

Hardness: it’s the resistance against an incision

3.2 Wood properties and constitution

Effort resistance: it is the resistance to an effort

Force

Internal effort

3.2 Wood properties and constitution

Sonority: is the way it transmits the sound

3.3 Wood extraction and processing

If we want to obtain a new wood board, we need to get wood from the environment and process it.

3.3 Wood extraction and processing

1º Felling: Cutting the trunk down with power saws.

3.3 Wood extraction and processing

2º Delimbing: Removing branches from the trunks.

3.3 Wood extraction and processing

3º Transportation:The wood is transported by truck, train or, in the past, by floating the trunks downstream.

Truck

3.3 Wood extraction and processing

4º Debarking: we remove the bark with special machines.

bark

3.3 Wood extraction and processing

5º Sawing trunks into boards:The trunks are cut to minimize defects, so

we get good quality wood

Boards

3.3 Wood extraction and processing

6º Drying: Removing moisture to prevent deformation.

3.3 Wood extraction and processing

7º Sanding:Finally, any imperfections are removed from the board.

3.4 Wood classification

The type of wood depends on the type of tree it comes from. Classification:

Soft woodHard wood

3.4 Wood classification

Soft wood: usually comes from resinous trees with perennial leaves. The wood has a clear color and it is easy to manipulate. For example, pine and fir trees.

pine

fir

3.4 Wood classification

Hard wood: comes from trees with deciduous leaves. The wood is dark in colour and difficult to manipulate. For example, oak and ebony.

oakebony

3.4 Wood classification

• Beech wood-For furniture• Oak wood- For barrels• Cherry wood- For musical

instruments• Mahogany wood- For

ornate furniture

3.4 Wood classification

You have to do exercise 8 from page 61, completing this table with 12

types of wood:Name of

the WoodColour Working Applications

Ebony Black Really hard

Figures and ornamental

Name of the Wood

Color Working Applications

Ebony Ebano Black Really hard

Figures and ornamental

Mahogany Caoba Clear pink HARD ornate furniture

Wild pine Pino silvestre

Veining with reddish-colored

Soft Furniture

Black poplar

Chopo negro Clear red Soft Carpentry

Beech Haya Pink Soft Models

Balsa Balsa Pale brown Soft Isolation and packaging

Red fir Abeto rojo Yellowish white

with grainSoft Musical instruments

European oak

Roble europeo

Clear Brown Hard Furniture and cabinetmaking

Walnut Nogal Brown Soft Furniture

3.5 Wood derivatives

We can obtain different materials from wood that improve the original properties.

We have two main groups of wood derivatives:

Engineered woodPaper

3.5 Wood derivativesEngineered woodThe engineered have special properties:They are more resistant to parasites

(Woodworms, termites..) and to humidity,

They are cheaper and more environmentally friendly.

3.5 Wood derivatives

This wood is transformed through an industrial

process in order to get different layers

3.5 Wood derivatives

Engineered wood examples:Plywood: several sheets of wood. Clipboard: thin slices of wood glued and

pressed. The thinner the chips, the more resistant the board.

MD (medium density) board: really small slices of wood that create a strongly engineered type of wood.

3.5 Wood derivatives

PaperWe obtain paper from wood after

several steps of an industrial process

1.The wood is chipped2.Pulp is obtained3.The pulp is washed4 It’s pressed and dried

3.5 Wood derivatives

The Paper Industrial process1.The wood is chipped 2.Pulp is obtained

3.The pulp is washed

4 It’s pressed and dried

3.5 Wood derivatives

Activity: • We have three kinds of wood: mahogany

wood, wild pine and european oak wood with their respective prices. Which one should I choose for a desk? Fill in the table

Type of wood

Price Use

100€

200€ 300€

3.5 Wood derivatives

Activity: • We have three kinds of wood: mahogany

wood, wild pine and european oak wood with their respective prices. Which one should I choose for a desk? Fill in the table

Type of wood Price Use

Wild pine 100€ Cheap furniture

European oak 200€ Furniture and cabinetmaking

Mahogany 300€ Ornate furniture

3.6 Wood ToolsWorking with wood

We are going to make objects with wood, but first we have to know how to…:

1. Measure and mark

2. Hold3. Cut and saw4. Drill

5. Refine6. Join7. Refinish

3.6 Wood Tools

1.To measure and mark

The first thing we have to do is to measure and mark the pieces of the object.

3.6 Wood Tools

1.To measure and mark

•We have to be careful when we measure, because one mistake can ruin our project.

3.6 Wood Tools

1.To measure and mark

•We have to make good use of the materials

1.To measure and mark

3.6 Wood Tools

Metal square: it’s used to mark 90º degrees

Carpenter ruler

Tape measure

Metal ruler

3.6 Wood Tools

Metal square: it’s used to mark 90º degrees

1.To measure and mark

3.6 Wood Tools

Carpenter pencil: you can sharpen it

with a knife

Punch: it’s use to make holes

Metal compass: it’s usedto transport measures

3.6 Wood Tools

2 To hold

We have to be careful before cutting or manipulating any object. We have to immobilize it.

3.6 Wood Tools

2 To holdG cramp: it holds the object to the table

Vice: It’s used to hold objects in place

3 To cut and saw

Once we have marked and held our material, we can cut it with a saw.

We have different saws to make different cuts

3.6 Wood Tools

3.6 Wood Tools

3 To cut and sawIf we want to cut wood we need a big set saw and if we want to cut metal we need a small set saw

Big set small set

3 To cut and sawThe coping saw: it’s used to saw thin boards and to makedifficult cuts

3.6 Wood Tools

3.6 Wood Tools

3 To cut and sawThe crosscut handsaw: it’s used to saw thick boards. It’s flexible so it can resist the efforts

3.6 Wood Tools

3 To cut and sawThe backsaw: it has a brace that helps to make straight cuts Brace

3.6 Wood Tools

3 To cut and sawThe hack saw: This saw is used to cut metal. It has a small set

Big set

small set

3.6 Wood Tools

4 To drillWhen we want to make a hole we can use a wood screw or a drill (manual or electric).

3.6 Wood Tools

5 To refine

When we saw the material we have to refine the cut, in order to obtain straight sides

3.6 Wood Tools

5 To refine

The refining tools are glasspaper and files

3.6 Wood Tools

5 To refine

We use files to refine metal and the rasp to refine wood

File=> MetalRasp => Wood

striationsTeeth

3.6 Wood Tools

6 To joinWhen we want to join together two boards or any pieces of wood we can hammer a nail into the wood

NailsHammers

3.6 Wood Tools

6 To joinWe can also use screws and screwdrivers

ScrewsScrewdriver

3.6 Wood Tools

6 To join

Each screw has a special head

3.6 Wood Tools

6 To join

We can put together wood using glue. It’s cheap and easy

3.6 Wood Tools

6 To join

Finally, we can also use a hot glue gun.

3.6 Wood Tools

h. Refinishing: Refinishing protects wood and improves its appearance. The wood has to be dry, clean and soft.

Dying. Water and alcohol Varnishing Wax finishing Oil finishing Painting