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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
