Woods and Processes Theory'

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WOOD
Woods and Processes Theory. Knowledge and
Understanding.
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Wood theory.
Woods can be divided into TWO main categories
softwood and hardwood.
Softwood Facts.

• Coniferous cone bearing.
• Thin needle-liked leaves and are evergreen.
• Grow relatively quick, they reach maturity within
  30 years.
• Cheaper than hardwoods.

Examples Pine, Spruce,Fir, Redwood.
Hardwood Facts.

• Hardwood trees are deciduous (lose there leaves
  annually)
• Big, broad leaves.
• Very slow growth can take 100 years to mature
• More expensive.

Examples Elm ,oak, ash, Maple, Cherry, Walnut,
Apple, Mahogany, beech, teak, balsa.
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Softwood theory.
PINE

• Relatively cheap
• Strong
• Lightweight
• Easy to shape with hand tools
• Can be oiled/varnished or painted.
•  

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Hardwood theory.
OAK

• Attractive, very durable, strong, heavy material
  which can be oiled/varnished/waxed.
• Commonly used in furniture and flooring.
•  

BEECH
Beech is classed as heavy, hard, strong, high in
resistance to shock and highly suitable for steam
bending. Good resistance to abrasive wear. Beech
is easy to use with most hand and machine tools.
It has good nailing and gluing properties and can
be stained to a good finish. Widely used for
furniture framing and carcass construction,
flooring and engineering purposes.
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Manufactured wood theory.
Man made woods are made from bits of scrap wood
which is stuck together by man
MDF
Medium Density Fibreboard
MDF is a type of wood formed by broken down and
powdered softwood, which is mixed with wax and
resin. This is then formed by applying high
temperatures to the MDF products to create the
finish. It is cheap and has a good surface finish
which can be painted to give a good effect.  
PLYWOOD
Plywood is a type of engineered board made from
thin sheets of wood, called wood veneers. The
layers are glued together, each with its grain at
right angles to adjacent layers for greater
strength and the grain on the outside surfaces
runs in the same direction. The venners are
joined under heat and pressure with strong glues.
Its cheap comes in large sheets, it is resistance
to cracking, shrinkage, twisting/warping, and its
generally strong and it is made from scrap wood.
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Wood theory test your self.
1. Wood is divided into two groups, they are
Hardwood
Softwood
2. Name two manufactured boards
Plywood
WOOD
MDF
3. Name two hardwoods
Cherry
Maple
4. Name two softwoods
Pine
Redwood
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Wood theory test your self.
5. Describe the key differences between hard and
soft woods?
Softwood Facts.

• Coniferous cone bearing.
• Thin needle-liked leaves and are evergreen.
• Grow relatively quick, they reach maturity within
  30 years.
• Cheaper than hardwoods.

WOOD
Hardwood Facts.

• Hardwood trees are deciduous (lose there leaves
  annually)
• Big, broad leaves.
• Very slow growth can take 100 years to mature
• More expensive.

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Wood Theory.
6. Describe any two of the following Veneer,
Plywood, Laminating  
Veneer
Veneer refers to thin slices of wood.  
What are they ?
How are they made?
A Natural Veneer is produced as a thin sheet of
wood of the same thickness by peeling or slicing
logs. One method has been illustrated bellow
Rotary Cut
The log is mounted centrally in the lathe and
turned against a razor sharp blade, like
unwinding a roll of paper.
Where are they used.
Veneer layers are usually glued and pressed onto
panels of different materials, to make products
such as
Kitchen worktops ,unit doors and furniture
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Wood Theory.
Laminating
Why do we need laminating?
Forming wood by bending can produce strong
shapes, however it is difficult to bend thick
pieces of wood.
How are they made?
An answer to this is to use thin veneers that can
be bent easily. These layers are glued together
and placed in a jig or former. When the glue is
set, the shape is removed from the jig and the
veneers retain their shape. The chair bellow is
an example.
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Wood Theory.
Plywood
How are they made?
Plywood is made up of a number of layers of
veneer, each layer glued with its grain at right
angles to adjacent layers for strength.