Transcript Wood and Modified Wood

Wood and
Modified Wood
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Humans have used wood for construction for
centuries because of its abundance and ease of
use.
The trunk is most used in this industry.
Two classes of wood:
– Hardwood
- Softwood
Hardwood is characterized as having more
resistance and longevity than softwood.
Types of Woods
Hardwood
Family of Tree
Leafy trees
(maple, oak)
Softwood
Resinous
(pine, cedar, spruce)
Uses
-Furniture
-Flooring
-Plank
- Plywood
(construction materials)
Transforming Timber
to Lumber
1. Cut down a tree.
2. The branches are
removed.
3. The trunk is cut into
sections.
4. The cut
sections are
transported to
a wood mill.
5. The bark is
removed.
6. The trunk is cut
into a beam.
7. The beam is cut
into wood planks
for construction.
Ex. 2 x 4
1x3
4x4
8. The wood
planks are
dried.
• Wood has certain characteristics that dictate
its application.
Ex. Durability (soft wood or hard wood)
Elasticity
Mass
Colour (white, pink, yellow, brown)
Tint (light or dark)
Resistance (decomposition)
Ease of use and assembly
• Unlike other materials (plastic, metal) the
life span of wood can be shortened due to
insects, mushrooms and mold.
Properties of Different
Types of Wood
Species
Hardness
Spruce soft
Resistance to
Usage
Durability Mass
Colour
Uses
medium
weak
light
- Whitishyellow
- reddish
- framework
- paper
Pine
soft
weak
Passable
resistance
light
Cream
Lightbrown
- furniture
- doors
Maple
hard
very strong
weak
heavy Light
brown
- floors
- furniture
Oak
hard
very strong
high
heavy Light
brown
- boats
- furniture
- floors
Ash
hard
strong
medium
heavy white
- hockey
sticks
- snowshoes
Modified Wood
• Natural wood can be transformed to modified
wood to lower costs.
• Modified woods are woods where substances
are added substances to obtain properties
different from natural wood.
Ex. Particle Board is made by
reducing medium quality wood
into particles then gluing it
back together.
Characteristics of Modified Wood
Types of
Modified
Wood
Plywood
Particle
Board
Composition
Advantages
Disadvantageous
3mm layers
stacked in odd
numbers
- Resists
cracks due to
contracting
and
expanding
- Economical
Glue can be toxic
Wood broken
down into
chips then
mixed with
glue and set to
a board due to
heat and
pressure
-Reuse wood
-Economical
- Uniform
properties
Glue can be toxic
Examples
Types of
Modified
Wood
Fiber Panels
Composition
Wood reduced
to fibers then
mixed with
glue and set to
a board by heat
and pressure.
Denser than
particle board.
Advantages Disadvantageous
Economical
Easy to use
Uniform
properties
Inconvenient
(Heavy)
Needs to be
painted
Glue can be toxic
Examples