Wood and Modified Wood

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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.

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• Two classes of wood
• Hardwood
• - Softwood

Hardwood is characterized as having more
resistance and longevity than softwood.
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Types of Woods Family of Tree Uses
Hardwood Leafy trees (maple, oak) -Furniture -Flooring
Softwood Resinous (pine, cedar, spruce) Plank Plywood (construction materials)
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Transforming Timber to Lumber

1. Cut down a tree.

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• 2. The branches are removed.
• 3. The trunk is cut into sections.

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• 4. The cut sections are transported to a wood
  mill.

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• 5. The bark is removed.

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• 6. The trunk is cut into a beam.

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• The beam is cut into wood planks for
  construction.
• Ex. 2 x 4
• 1 x 3
• 4 x 4

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• 8. The wood planks are dried.

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• 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

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• Unlike other materials (plastic, metal) the life
  span of wood can be shortened due to insects,
  mushrooms and mold.

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Properties of Different Types of Wood
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Species Hardness Resistance to Usage Durability Mass Colour Uses
Spruce soft medium weak light - Whitish-yellow - reddish - framework - paper
Pine soft weak Passable resistance light Cream Light-brown - 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
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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.
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Characteristics of Modified Wood
Types of Modified Wood Composition Advantages Disadvantageous Examples
Plywood 3mm layers stacked in odd numbers - Resists cracks due to contracting and expanding - Economical Glue can be toxic
Particle Board 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
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Types of Modified Wood Composition Advantages Disadvantageous Examples
Fiber Panels Wood reduced to fibers then mixed with glue and set to a board by heat and pressure. Denser than particle board. Economical Easy to use Uniform properties Inconvenient (Heavy) Needs to be painted Glue can be toxic