Design Technology GCSE - Timber

What is timber? [1 mark]

A wood that has come from a tree trunk that has been dried and cut into planks.

What is a hardwood? [3 marks]

- Comes from a tree with broad leaves.

- Comes from a deciduous tree.

- Takes longer to grow than softwoods.

Why are hardwoods more expensive than softwoods? [1 mark]

- Take much longer to grow.

Compare oak to mahogany, list their advantages and disadvantages [6 marks]

Oak:

Advantages:

- Strong

- Durable

- Attractive grain

Disadvantages:

- Corrodes iron/steel

- Hard to work with

Mahogany:

Advantages:

- Attractive grain

- Easy to work with

Disadvantages:

- Expensive

- Rarer.

- Oil it produces may cause rashes.

What 2 woods would you use for model making? Why [4 marks]

- Balsa:

*Lightweight

*Easy to cut

- Jelutong:

*Even, closed grain structure makes it easy to

cut/shape.

Which hardwoods are susceptible to rot and insect attacks? [2 marks]

- Birch

- Ash

List 3 advantages and 2 disadvantages of beech [5 marks]

Advantages:

- Tough wood

- Does not crack/split

- Hard

Disadvantages:

- Expensive

- Not resistant to moisture

What hardwood is often used as veneer? [1 mark]

Birch

What is a softwood? [3 marks]

Wood that

- has needles and cones

- has a lower density/growth time than hardwood

- is most commonly an evergreen.

What two softwoods would be used for outdoor equipment? Why? [3 marks]

- Larch

-Cedar

- Oil makes it water-proof

What disadvantage do both cedar and larch share?

Expensive

Why is pine used more frequently than other softwoods for interior construction? [5 marks]

- Very durable

- Easy to work with

- Quite cheap

- Reasonably strong

- Lightweight

What is one disadvantage of pine? [1 mark]

Can wrap/crack/splinter more than some other woods.

What are two disadvantages of cedar compared to pine?

- More expensive

- Not as strong

What colour does larch turn into? [1 mark]

- Silvery/gray

What types of climates can softwoods be found in? [2 marks]

- Cold climates

- Temperate climates

What type of climate can hardwoods be found in? [2 marks]

- Tropical climate

- Temperate climate

How is chipboard made? [3 marks]

- Wood chips

- Are mixed with glue

- And pressed into flat sheets

Why is chipboard cheap? [1 mark]

Because it uses waste products as a material.

What are some disadvantages of chipboard? [2 marks]

- Surface is rough (so it needs to be plastic coated)

- Not very strong

- Not water resistant

How is plywood made? [3 marks]

- Tree trunk is sliced into veneers.

- Veneers are glued together

- With the grain lines going in alternate directions.

What are the advantages of plywood? [3 marks]

- Structurally strong

- Resistant to cracking/twisting

- Looks like wood

What are the disadvantages of plywood? [3 marks]

- Quite expensive

- Edges can look rough

- Susceptible to water if the wrong grade is used

How is MDF made? [4 marks]

- Tiny fibres of wood

- Are glued

- And compressed

- Provide a dense solid board

What are the advantages of MDF? [2 marks]

- Cheap

- Easy to make

What are the disadvantages of MDF? [3 marks]

- Not very strong

- Very heavy

- Absorbs water

What are knots? [1 mark]

- Mark that appear where a branch grows out of a tree.

Why is it difficult to work with knots?

- Harder to cut with saws/chisels

- Can fall out/leave hole

- Have to be treated with knotting paint.

What is the grain structure of softwoods compared to hardwoods?

Softwoods:

- Narrow annual rings

- Close grained

Hardwoods:

- Large vessels on the surface

- Open grained

What type of wood does grain filler have to be applied to? Why and for what purpose? [2 marks]

- Hardwoods because the grains are on the outside,

- Meaning that paint would be sucked in.

What is elasticity and what is one example in wood? [2 marks]

- The ability to stretch without alteration

- Yew

What is the difference between compressive strength and tensile strength? [2 marks]

- Compressive strength measures a crushing force.

- Tensile strength measures a pulling force.

What is shear force? [1 mark]

A force acting in opposite directions

What is a torsion force? [1 mark]

A twisting force

What woods have high tensile strength? [2 marks]

- Ash

- Oak

State one positive impact manufactured boards have on the environment and one negative. [2 marks]

- Recycle waste wood from manufacturing processes.

- However they contain plastic and other materials which makes them harder to rot.

What makes timbers as materials sustainable? [3 marks]

- Rot away in time

- Be used as biofuels

- Leftovers can be used to make manufactured boards.

What are 3 problems caused by deforestation? [3 marks]

- Habitat destruction

- Increase in greenhouse gas

- Poor soil

- Higher chance of landslide

- Timber processing requires energy

- Most wood comes from s. America so it has to travel miles.

What is seasoning? [1 mark]

The process of drying timber to remove moisture.

What does seasoning prevent? [1 mark]

- Warping/bending of timber

Compare the different types of seasoning and their effectiveness [5 marks]

- Air seasoning

* Leave planks out for years to dry

- Kiln seasoning

* Stack planks in a room and dry with steam

- Kiln seasoning is better because it is quick/efficient

What is upcycling? [1 mark]

- Repurposing an object without recycling it.

What is Dutch Elm Disease caused by? [1 mark]

- A parasite that eats trees.

What is the ash dieback disease caused by? [2 mark]

- Fungus

- kills tree by entering through the leaves and spreading through trunk.

How can woods be treated to prevent rotting? [2 mark]

- Pressure treatment

- Preservatives are treated deep into the wood.

What is a common chemical used to prevent rotting? [1 mark]

- Tanalith E

What is pressure-treated timber referred to as? [1 mark]

Tantalised timber

What cost factors must be considered for sourcing materials? [3 marks]

- Quality of material

- Manufacturing process

- Treatment

What social factors must be considered for sourcing materials? [2 marks]

- Social groups

- Trends/fashion

What is built-in-product obsolescence? [2 marks]

- Manufactures deliberately make products designed to break after a while

- So the consumer must buy it again

What is PAR? [3 marks]

- Planed all round

- Surfaces are planed

- Slightly rounded edges for easier handling

What is PSE? [2 marks]

- Planed square edges

- Surfaces are planed

- Edges are left square

Where would PSE be used? [1 mark]

Joinery timber

Where would PAR be used? [1 mark]

Constructional timber

Where is the stress of a beam mostly concentrated? What will happen if left unchecked? [2 marks]

- Stressed is concentrated at the bottom

- The beam might bend

How can you prevent beams from bending? [1 mark]

- By pre-stressing the beam

What is a strut? [1 mark]

A structural component that resists longitudinal compression.

What could a designer add to prevent a square frame from collapsing? [2 marks]

- Putting a thin panel inside the frame

- Adding a diagonal strut across each corner.

- Adding a strut corner to corner to make two triangles.

What is a laminate? [1 mark]

- A thin layer of material

What is a more effective alternative to steam bending? [1 mark]

Lamination

What is lamination used for? [2 marks]

- Bend wood

- Reinforce wood

What is a brace bar? [1 mark]

- Diagonal, triangle shapes that are added to frames.

What is a tie bar [2 mark]

- A rod that is in tension

- Often made of steel

What is the difference in the uses between a brace bar and a tie bar in frames? [2 marks]

- Brace bar is for strengthening frames

- Tie bar is for stopping frames from stretching.

What are the differences between a routing, sawing and mortiser? [5 marks]

- Routing:

* Hand power tool

* Hollow out area/cut shapes

* In hard materials

- Sawing:

* Prepare timber quickly

- Mortiser:

* Used to cut square holes

How does bag pressing ensure uniform pressure? [3 marks]

- Mould and laminate are placed inside a sealable bag and closed

- Air is sucked out

- Pressure difference between inside and outside created.

What are some techniques for quantity production? [3 marks]

- Jigs

- Fixtures

- Templates

- Patterns

- Sub-assembly

- CAM

- Quality control

- Working with tolerance

- Efficient cutting

- Knock-down fitting

What is the difference between jigs and fixtures? [3 marks]

- Fixtures are used to control the location

- Jigs can control the location and motion.

A designer wants to drill a very deep hole, what drill bit should he use? [1 mark]

- Auger

A designer wants to cut a large hole into a piece of wood, but can't use a hole saw. What two things could this suggest about the wood/the goal of the designer? How do you know? [2 marks]

Hole saw comes at a limited range)

* Hole he wants to cut is too

large

- Hole saw can only cut thin materials

*Board could be too thick

What three drill bits could be used to cut large holes in wood? [3 marks]

- Flat bit

- Forstner bit

- Hole saw

Using what drill bit can a designer cut small holes? [1 mark]

- Twist drill

A designer wants to enlarge a hole, what drill bit can he NOT use? [1 mark]

- Flat bit

What is the difference between the uses of a hand saw and a tenon saw?

- Hand saw:

* Cut long/deep cuts

- Tenon saw:

* Cut smaller/more precise

cuts

When would a coping saw be used? [2 marks]

- Cut shapes out of thin wood

- Cut curves

When can a scroll saw not be used?

When the wood is too thick.

What are some disadvantages of the jigsaw? [2 marks]

- Difficult to cut straight lines.

- Blade sometimes wanders into material.

What 3 saws are non-electric? [3 marks]

- Hand saw

- Tenon saw

- Coping saw

What 4 saws are hand-held? [4 marks]

- Hand saw

- tenon saw

- Coping saw

- Jigsaw

What machinery is used to spin and hold the wood for chiseling? [1 mark]

- Wood-turning lathe

What one precaution must be taken when using a plane?

- When it is not used, it must be kept on its side to avoid the blade from being damaged.

What is the difference between screws and nails? [1 mark]

- Screws can be extracted easily, nails can't.

What are the two types of screws? [2 marks]

-Slotted

- Phillips

A designer wants to nail some timber together, but wants to avoid damaged being done to the grain. What nail should he use? [1 mark]

- Oval nail

A designer wants to nail a small board onto timber, what nail should he use? [1 mark]

- Panel pin

What are round wire nails for?

- Joining thin materials.

What type of glue is used on wood? [1 mark]

PVA glue

What can be used to waterproof timber? [1 mark]

Oil.

What surface treatment should a designer that wished to cover the natural wood grain completely use? [1 mark]

- Painting

A designer wants to make a pale wood piece more vibrant without completely hiding its grain, what surface treatment should he use? [1 mark]

- Staining

What does varnishing do? [1 mark]

Adds a clear coating to wood that dries to a shine.

What side effects can varnishing cause? [1 mark]

- It can scratch/expose the wood

A designer wants to treat a wooden surface while maintaining a plain, natural look. What surface treatment should he use? [1 mark]

- Wax

What is shellac? [3 marks]

- A cloudy resin secreted by a beetle

- Lots of layers are rubbed and polished

- Creates a french finish

Where is shellac used? [1 mark]

- Expensive furnitures

What are some disadvantages of shellac? [2 mark]

- Damaged by water

- Damaged by heat