Section A - Materials and their working properties - natural and manufactured timbers Flashcards
Timber is ______,____________,_________
Timber is recyclable, renewable and reusable
Timber is a ____ material
Timber is a natural material
What is the original source of timber
The original source of timber is trees
What are the names of 2 classifications of wood
Hardwoods and softwoods
Draw a typical leaf from a tree from each of the two categories of natural timber
Define hardwood
Hardwood - woods that come from deciduous trees
Define softwood
Softwood - woods that come from coniferous (evergreen) trees.
Explain why hardwoods tend to be more expensive than softwoods
Hardwoods are woods that come from deciduous trees.
Softwoods are woods that come from coniferous (evergreen) trees.
Deciduous trees take a long time to mature (than coniferous trees) before being able to be felled (cut down) and turned into useable timber - as a result they tend to be more expensive than softwoods
List the characteristics of a softwood tree
A softwood tree:
mostly evergreen
retain leaves all year round
Needle - or scale-like leaves
Bear cones
Branches are located the whole length of the trunk
Triangular shape
List the characteristics of a hardwood tree
Hardwood tree
Mostly deciduous ( trees that generally lose their leaves in the autumn)
Shed leaves each autumn
Typically flat leaves
Branches are grouped at the top of the tree
Examples of hardwoods
Ash
Beech
Mahogany
Oak
Balsa
Properties of ash
Tough and flexible,
wide grained
good for steam bending
Finishes well
Common uses of ash
Sports equipment (e.g. cricket stumps and bails) (because it is tough and flexible material, making it durable enough to withstand impact from a cricket ball travelling at speeds of up to 160 kilometres per hour
, ladders
Properties of beech
Hard, strong, close grain
Prone to warping and splitting
Durable
Finishes well
Common uses of beech
Furniture, children’s toys, workshop tool handles and bench tops
Properties of mahogany
Strong and durable
Available in wide planks
Fairly easy to work with but can have interlocking grain
Finishes well
Common uses of mahogany
Good quality furniture, panelling and veneers
Expensive - so its used for good quality furniture
Properties of oak
Hard, tough, durable, open grain
Can be finished to a high standard
Finishes well
Common uses of oak
Timber framed buildings, high quality furniture, flooring
Properties of Balsa
Strong and durable
Lightweight
Easy to work with
Wide-spaced grain due to it being a fast-growing hardwood
Prone to snapping
Common uses of balsa
Model making
Floats
Rafts
How long does it take coniferous trees to reach maturity
Coniferous trees are quick growing and take around ten years to reach maturity before felling.
Explain the advantages of coniferous trees being fast growing
Coniferous trees are quick growing and take around ten years to reach maturity before felling.
This makes them an extremely sustainable group of materials as they are renewable
Examples of softwoods
Larch
Pine
Spruce
Properties of larch
Reddish in colour and has a striking grain pattern
Tough but easy to work, although quite resinous and prone to splitting
High sap content gives it good water resistance
Naturally resistant to rot
Easy to machine
Common uses of larch
Fencing, fence posts, cladding and decking and joinery
(this is because of its toughness and natural resistance to rot from moisture. It is so durable in a moist environment)
very few types of softwood that is used outside
Properties of pine
Straight grained
Light yellow in colour
Soft and easy to work
Can be quite knotty
Lightweight
Easy to form
Common uses of pine
Interior joinery and furniture
Window frames
Properties of spruce
Creamy white in colour
Easy to work with small knots
Lightweight with good resonant properties
Common uses of spruce
Bedroom furniture
Stringed musical instruments
What types of products are softwoods most commonly found in
They are most commonly found in products designed to be used indoors and for joinery as most softwoods have poor resistance to decay and require the addition of preservatives before being used outside
Which type of woods are less dense
Softwoods are less dense than hardwoods - but not always
Balsa - hardwood - but it is soft, lightweight - can be easily cut with a craft knife
Name three different manufactured wooden board
Medium density fibreboard (MDF)
Plywood
Chipboard
Two categories of manufactured boards
Laminated boards (produced by gluing large sheets or veneers together)
Compressed boards (are manufactured by gluing particles, chips or flakes together under pressure)
Advantages of manufactured boards
They are available in much larger sheets than solid timber
They have consistent properties throughout the board
They are more stable than natural timbers, meaning they are less likely to warp, shrink or twist
They can make use of lower grade timber, so can have environmental benefits
They can be faced with a veneer or a laminate to improve their aesthetic apprearance
Due to their consistent quality, they are well suited for CNC machining and volume production
Describe the manufacture of Medium density fibre board
MDF is a compressed board that is manufactured from fine fibres of wood combined with a synthetic adhesive (usually formaldehyde resin)
The MDF pulp is compressed between two heated plates where the adhesive bonds the fibres together.
What type of wood is used for the manufacture of MDF
MDF makes used of low-grade softwood and hardwood timber, along with waste created from other wood manufacture processing.
Why should care be taken when manufacturing MDF
Are there any potential risks when manufacturing MDF
Care should be taken to limit the dust produced when working with MDF as it can cause respiratory issues due to the size of the fine dust particles
Properties of MDF
The surface of MDF boards is smooth - which makes it easy to apply a high quality paint finish
The edges of the board are fibrous as so need additional sealing before
painting
Explain why MDF is denser than most other manufactured boards
The MDF is compressed to 0.25 per cent of its original thickness, which is why MDF is denser than other manufactured boards
State the types of specialist versions of MDF
Moisture-resistant board
Fire-resistant board
Flexible MDF (it has a series of small grooves or kerfs cut into one side of the material that allows the board to bend around a radius.) - This particular form of MDF is often used in shop fitting applications
What is MDF commonly faced with and why?
MDF is commonly faced with a veneer to improve its aesthetics
Examples of common veneered or faced boards
Oak-faced
Ash-faced
Beech-faced
