Timbers Flashcards
What are Timbers
Wood prepared for use in building and carpentry.
What are the qualities of a Softwood (Coniferous) Tree (get 5 at least)
-They mainly grow in a cooler climate like Canada
-These types of trees are known as ‘cone-bearing’ trees, which are why the are called conifers
-The trees usually grow tall and stright which make it easy to cut into long straight planks for manufacturers
-They have a looser grain structure
-They are often used as a building material
-They are usually softer and easier to work with
-They grow quite faster and so are cheaper
-They are evergreen, meaning that they don’t loose their leaves
Examples of Softwood Trees
- Pine
- Spruce
- Douglas fir
- Redwood
- Cedar
- Larch
What are the qualities of a Hardwood (Deciduous) Tree (get 5 at least)
-You can have evergreen hardwood trees (like holly) which do not loose their leaves and Deciduous trees which lose their leaves in winter
-They are broad-leaved trees and the seeds are enclosed in the fruit that the tree produces
-They are slower growing trees, meaning it can take 100 years to grow fully
-Most evergreens are found in tropical and subtropical zones and countries, such as South America
-These are usually quite hard
-Tend to have a tighter grain
-They can be very expensive
Examples of Hardwood Trees
- Oak
- Ash
- Mahogany
- Teak
- Birch
- Beech
What are the qualities of a Manufactured Boards (get 5 at least)
- Boards are available in many thicknesses
- Boards are inexpensive so are often used instead of real woods
- Manufactured boards are often covered with a thin layer of real wood which is called veneer this improves their appearance or properties
- Manufactured boards are timber sheets which are produced by gluing wood layers or wood fibers together
- Manufactured boards are often made using waste wood
- Manufactured boards have been developed mainly for industrial production as they can be made in very large sheets of consistent quality
Examples of Manufactured Boards
- Plywood
- Marine plywood
- Aeroply
- Flexible plywood
- Chipboard
- Medium density fibreboard (MDF)
Veneers and melamine formaldehyde laminates.
What is a Performance Characteristic
Each material has properties that make them good/bad for specific tasks. The properties of materials must be considered when designing a product.
Some Performance Characteristics of Timber (Get at least 5)
- Warpage
- Steam Bending
- Resistance to decay
- Joining
- Forming
- Surface Defects
- Toxicity
- Splitting
- Shrinkage
- Grain Pattern
- Grain Direction
- Surface Defects
Explain why materials are available in stock forms
Materials are available in stock forms so that they can be used for different purposes across different industries (i.e plastic granules used for moulding, but plastic powder can be used for coating). Stock forms also offers uniform scale of the shape and size of materials, while also making materials easier to transport, as transporting an entire tree trunk would be much harder than planks.
What are the 6 Stock Forms of Timber
- Rough Sawn
- Planed Square Edge (PSE)
- Planed All Round (PAR)
- Natural Timber
- Manufactured Board
- Mouldings
How can you tell if Timber is Rough Sawn
If the timber is not smooth
How can you tell if Timber is PSE (Planed Square Edge)
If all the edges are smooth all round
How can you tell if Timber is Planed All around (PAR)
If all the sides and edges are planed square, straight and level, leaving a smooth finish and ready to use.
How can you tell if Timber has been Moulded
If it’s on skirting boards, frames, e.c.t
How can you tell if Timber has been Veneered
If it’s thin cuts of wood glued onto other materials
Why is Recycling Timber Good
Using a recycled timber product reduces deforestation and retains the locked-in carbon. This helps reduce greenhouse gases going into the atmosphere and contributing to climate change.
What is Seasoning Timber and what 2 Types of Seasoning are there
- Natural Seasoning
- Kiln Seasoning
Advantages and Disadvantages of Natural Seasoning for Timber
Advantages:
- Cheap
- Some say the timber is stronger than when it is Kiln Seasoned
Disadvantages:
- Very slow (a year per inch thickness)
- Bugs and fungus survive
- Water content hard to control accurately
- End of planks can split
Advantages and Disadvantages of Kiln Seasoning
Advantages:
- Accurate water content achieved
- 12% or lower moisture content achievable
- Kills bugs and fungus
- A Fast Process
Disadvantages:
- Expensive compared to Natural Seasoning
What are the 4 Timber Defects
- Splitting
- Knots
- Timber Decay (Dry Rot)
- Woodworm
What happens when Timber Splits and how can it be avoided
• Usually occurs at the end of a plank
• Ends are cut off to remove splits
• Generally an unavoidable problem
• Painting the ends of planks can help slow down the drying of the ends
What are Knots in Timber and when are they good/bad
Knots are where a branch was attached to the tree
- Live knots are OK and can be decorative
- Dead knots need to be avoided
What is Timber Decay - Dry Rot
It is a serious problem caused by incorrect seasoning or poor building maintenance.
Dry Rot is caused by timber being over 20% moisture content and not ventilated.
What is Woodworm and how can it be spotted
The common furniture beetle lays eggs on timber. The larvae eat the wood for a year and then emerge as adult beetles in the spring. “Frass”, or wood dust is a sure sign of woodworm
