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Section B Timbers: Why use this revision guide? This section is worth 60 marks and will contain a mixture of different question styles in the form of maps. The exam paper will include short answers and sketching, calculation a 5 mark question, extended type questions. Revision Tips:• Start your revision early (do not revise at the last minute)• Make clear well ordered notes about all the sections of timbers including the core

section• Test yourself at the end of each section. Work through exam style questions• Work through past exam papers and sample assessment materials• Identify the areas of maths type questions and practise the section.• Work through corrections and identify areas you mat need for further practice.

Areas to Revise Revised

7.1 Design contexts

7.2 Sources of timber

7.3 Selection of timber

7.4 Strengthening of timber

7.5 Stocks forms/types

7.6 Manufacturing processes

7.7 Equipment and processes used to make prototypes

7.8 Surface treatments and finishes for functional and aesthetics purposes.

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Timbers

Strong

Lightweight

Looks attractive

Lightweight

Used in the construction Industry

Furniture

Traditional hand craft techniques

People used to use whatever timber grew near where they lived

Oak grown in UK naturally strong hardwood.

Pine is used as its imported a softwood.

Mahogany used to be imported from tropical rainforests

South America, Africa, Indonesia

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imber Deciduous: A tree

that loses its leaves in the winter.

KEY TERMS• A hardwood tree comes from broad leaves as shown. • Deciduous trees grow slower taking more than 100

years to grow.

Broad leaves

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• Softwood tress have needle-like leaves and seeds in a cone just like a Christmas tree.

• Most are evergreen which means they have leaves all year around.

• Softwood trees grow quite quickly can be used for timber after about 30 years.

• Available in narrow planks, grain lines give it strength especially lengthways.

Natural Timbers-Softwoods

Seeds in a cone Needle-like leaves

Manufactured timbers

If you choose a wood make sure you justify why have chosen it by talking about its properties , why is this material suitable.

Exam Tip

Plywood MDF• Use timbers to make large manufactured boards so if you

want large thine sheets of wood you have to used manufactured boards. Plywood, MDF are manufactured boards.

Where different timbers can be found around the world

• Chipboards: made by using wood chips mixed with glue and pressed into flat sheets, uses waste material.

• Not much structural strength• Surface is rough and usually plastic coated.• Uses: desktops, kitchen worktops, cheap flat-pack

furniture.

Chipboard

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Grain: Fibres run the length of a tree trunk, which give it its strength.Density: Weight in grams per cubic centimetre or kilograms per cubic meter. The compactness of the wood which make it have high strength to weight ratio.

KEY TERMS

Physical characteristics of timber

Knots

Colour

Grain structure and densityWorking

Properties

ElasticityTensile strength

Compressive strength

Social Footprint

Trend forecasting

Impact of logging on communities

Recycling and disposal

• This is were a branch grew out of the tree. Knots can also fall out, visually appealing.

• Different woods have different colours from pale to dark.

• Spilt into hardwoods and softwoods.

• Open grains refer to softwoods

• When applying finish to softwoods they need sanding first.

• Use correct meaning of words that describe properties of materials.

• Ability to stretch and return to its original length and shape. Example Yew used for making archery bows

• Amount of force a material can withstand when being pulled. Timbers have 3 to 4 times more than compressive strength.

• The amount of force it can withstand when crushed.

• More dense the wood the better the better the compressive strength such as Hickory.

• Use softwoods from sustainable sources.

• Manufactured timbers used in construction.

• Brings in money and jobs• Amazon (poor area) bad management

large companies log where indigenous people live.

• Destroys way of like and animal habitats

• Biodegrade and rot away in time• Composite materials harder to dispose

of such as chipboard as covered in plastic.

• Cannot recycle and remould into shape. • Can be burned to make useful heat such

as Biomass fuel to make electricity.• Clean Timber (not mixed with any other

material) is turned into chipboard and MDF.

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Ecological Footprint

SustainabilityDeforestation

Habitat destruction & loss

Processing

Transportation

Wastage

Pollution

Ecological Footprint: The amount of environment needed to make goods and services support a particular lifestyle. Includes product lifecycle, cutting down trees, seasoning timber, manufacture, disposal of product.

• Always trees available for use• Hardwood trees take longer to

grow 100 years, not replanted.• Softwood trees 30 years to grow

and replanted managed by theFSC see logo.

• The Forest Stewardship Council (FSC) lets timber producers use this logo showing the wood comes from a sustainable managed source.

• Trees cut down faster than they can grow.

• Major problem in the developing world South America and Africa.

• Less trees more gases causing global warming

• Animals lose their habitat no nowhere else to go.

• Tigers, Gorillas, elephants, birds and insects are at risk of being extinct if deforestation continues.

• Tree trunk is sawn into planks• Dried out planks by the

process of “seasoning” • Seasoning can be done

naturally or kiln drying which uses energy.

• Leaves and small branches are not processed.

• Larger branches and waste from the trunk made into planks can be turned in chipboard or MDF.

• Timber is expensive so need to reduce wastage.

• Manufactured boards when cut give off fine dust which is toxic so masks, gloves and eye protection is used.

• Trees are transported by lorries which burn fossil fuel this increases carbon footprint.

• When burning trees this gives off carbon dioxide, increasing the greenhouse effect.

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imber Seasoning: Reducing the water content of timber to 10-18%.

Warping: Bending or twisting that happens to timber as it dries out.

KEY TERMS

Selection of Timber

SustainabilityEnvironmental factors

Genetic engineering

Seasoning

Upcycling

Use of stock materials

Use of specialist materials

Explain one benefit for the environment of using upcycled material to make a bookend.

Exam style question

(2 marks)

Hurricanes, storms and disease

Cost factors (Quality of material)

• Choose the most suitable material.

• 85% wet tree when cut needs to dry.

• 12% suitable amount of moisture in wood for indoor use.

• Drying process is called seasoning.

• Kiln drying is quicker and kills insect eggs.

• Trees with altered DNA which can grow faster, resistant to disease.

• Where a designer uses timber to create a style such as rustic or shabby chic. e,g and old bench repaired and painted.

• Timber from this source does less damage to the environment as its reused or recycled. • In the UK Dutch Elm disease killed the Elm

tree• Ash trees have died from ash dieback.• Storm damage trees take time to grow back.

• Timber is sorted, graded and sold for different purposes.

• C16 softwood grade used for window frames and doors

• C24 grade stronger than C16 used for roof trusses, which are wooden frames that support the roof.

• Timbers are sold in standard sizes which is called stock materials. Using stock sizes saves time in cutting wood smaller, reduces waste.

• Marine plywood waterproof outdoor use.

• House timbers treated with flame retardant chemicals.

• Expensive hardwood veneers which are laminated on the outside of cheaper timber.

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Selection of Timber products

Treatments

Use for different social groups

Trends, fashion and popularity

The effects of mass production

Cultural ethics

• Avoiding offence: Understanding different cultures, religions when making products as not to offend.

• Making sure the product is designed for a specific user, age. need and is safe to use. Think of design specification.

Built in product obsolescence

Consumer society

• UK and developed world is wealthy products are cheap so people buy products they do not need.

• Companies advertise products to sell which we don’t really need.

• People get into debt by buying too many products which impacts on the environment using up resources.

• Chemicals on timbers can reduce the burn time.

• Timber can be pressure treated a process where preservative is forced deep into the wood making it less likely to rotting

• One chemical is called “Tanalith E” or tanalised timber.

• Cheaper materials, such as chipboard and MDF are used by the mass market, Flat pack furniture (IKEA).

• Bespoke expensive furniture made for wealthier client user groups using materials such as hardwoods, oak.

• These trends come and go aesthetics of a product has to appeal to the consumer.

• Automated factories which can make manufactured boards cheaper than using a larger manual workforce making the same product.

• Machines do more work so lower few skilled jobs.

• Computer programmers run the machines that have taken jobs of the manual worker.

• Products have a short life span on purpose.

• Manufactures deliberately make parts that fail so you throw the products or part away and then buy a new one.

• Not environmentally friendly as more rubbish is created rather than fixing the product or part.

Key points:• Timber may be selected for its

strength, cost appearance• Timber is treated to improve

resistance to rot and fire.• Furniture is made from cheap

laminated chipboard.

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ber Forces and stresses that act on materials.

Reinforcing and stiffening techniques.

Rectangle can collapse under force. So to reinforce and strengthen it a strut is used.

Natural forces within timber as it grows.

When a tree grows the branches grow out of it. When a tree leans over to support the branches this stresses the wood. So when the tree is cut into planks the stress is then released causing the wood to bend or crack.

Keywords: Fabrication is the process used to make parts for a product. Assembly processes are processes used to put the parts together.

1).

2).

3).

Wood laminating process

Braces and ties bars are also used to strengthen a frame

Brace

KEY TERMS

Lamination: Bonding several thin layers together to make a thicker material

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sizes Sizes: Imperial and metric.

As wood is sold in metric sizes its still the equivalent of the nearest old imperial size for example: 100mm x 50mm used to be called in imperial 4 inches x 2 inches and many carpenters will still call it two- by- four.

PAR (planed all around).This means all four surfaces have been planed with slightly rounded edges for easier handling, safer used in construction frames and interior walls.

PSE (planed square edge).This means all four surfaces are planed but the edges are left square. Sold in long lengths 1.8 metres.

Key points: Timber is sawn into standard sizes by the sawmills PAR and PSE are planed timber, which has smooth surfacesMouldings can be used to add decorative trim to productsManufacture boards come in standard-sized sheets, in a range of thicknesses such as 3mm 6mm 9mm 12mm

Timber is normally sold by the sawn size common sizes are: 15mm x 75mm 15mm x 100mm 15mm x 150mm 50mm x 50mm

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What power tools cut shape timbers?

Circular saw

RoutingBandsaw

Bench-top mortiser

• Rotating cutter with lots of different shape cutters.

• Prepare wood quickly

• Sawmills larger versions of this to cut tree trunks

• Cutting thicker wood on the bandsaw will result in edges not being square.

• Prepare wood quickly

• Makes a square hole. (mortise slot).

• Round centre of the chisel drills a round hole and square chisel cut the corner.

Mortise cutting tool with slot.

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Scales of production: Choosing the right scale of production is important when making a product having an expensive factory makes the product cheaper, but you will have to sell a lot of them to pay for the factory.

A company has been batch producing coffee tables. A large retailer has just ordered 3000 of its tables. Explain two reasons why the directors should change to mass production.

Exam style question

(4 marks)

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Techniques used for quantity production

When we prepare a piece of timber you mark one face flat which is called the face side. Using face side, get one edge square with it. This is called the face edge.

Jigs: these are used to guide a drill or saw accurately in the right place. Useful in batch production methods as the jig is reusable

Drilling Jig

Fixtures: hold the workpiece in place when it is cut or shaped.

Templates: made from paper, card for single use or wood metal if used lots. Accurate and used in batch production.

Patterns: Similar to a template also know as a collection of templates this might include several individual templates to make the whole product. Expensive patterns accurately made.

Sub-assembly: These are components which have been assembled and used as an individual component in a larger product for example DVD module which inserted into a different desktop computers.

CAM: Uses a computer to guide cutters on a CNC machine “computer numerically controlled”. Used with CAD design packages for example in school 2D design tools. Advantages accurate, operates 24/7. High start up costs and training of staff. Used in one-off and batch production.

CNC machine

Quality Control: This is a process where products made are checked for build quality before sale. At stages of making samples are tested by inspection making sure its correct. If faults are found then the making process is stopped.

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Equ

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s Tools and equipment

Hand held cordless drill

Pillar drill Try square Jack plane

Wood turning lathe

Bevelled edge chisel

Marking gauge

Battery operated drill used for site work. No power lead so can work away from a power source.

Workshop drill makes 90º vertical holes. Requires claps to hold work in place when drilling.

Used to mark a line at 90º to an edge and check if something is square.

Good for making long flat surface or edge on larger pieces of timber.

Available in a range of widths. Good for general purpose woodworking.

This lathe is used to turn a long piece of timber, so the operator can chisel away the edges to create complex designs such as table legs.

Used to mark a line parallel to an edge – advantage is that it can mark out several piece of timber at the same measurement, the point or (spur) scratches the timber so it is vital that the gauge is set correctly.

(Spur) point

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s Drill Bits Drilling: A drill is used to make holes into timbers. The table below shows the advantages and disadvantages of using each type of drill bit.

KEY TERM

Flutes:The twisted spirals along a drill bit that remove the swarf when cutting.

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Cutting: Timber is cut with a saw. A saw has teeth on it that cut the wood as the saw is pushed over the wood. There are different types of saw, but they all do the same job of cutting.

Key points to remember: The name and purpose

of the hand tools. The name and purpose

of wood working machines.

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s Removing waste from timbers: The table shows the hand tools you can use to remove waste from timbers.

Abrading: Abrasive paper such as sandpaper is used to remove wood and leave a smooth surface finish on wood. The smaller the grit on the paper the bigger number so P80 is coarse and used to remove heavy amounts of wood. P120 is used for a smoother finish and P240 gets a really smooth surface finish.

Carving: Woodcarving is used by shaped chisels to cut away wood for decorative effect. This is know replaced by CNC machinery.Files, rasps and surforms: they have teeth on them used to abrade away wood and come in a range of shapes.

Sand paper

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Fabricating and constructing

Veneering: Thin layer of wood can be damaged. Plywood is made of layers of veneer laminated together

PVA: PVA (Polyvinyl acetate) common wood glue thick white liquid sets clear.

Nailing: These come in various shapes and sizes and are hammered into wood. Sometimes a pilot hole is drilled into the wood before the nail is put in to prevent the wood from splitting.

Round wire nails

Woodscrews: Slotted type (flat) woodscrew and Philips (cross type) create tight fit, make strong joint.

Countersink: This makes the head of the screw fit flat to the surface of the wood. A pilot hole is drilled first. Then a clearance hole is drilled first to fit the screw head.

Contact adhesive:

Oval nails Panel pins

Large flat head so they don’t pull through the wood

Spread the grain less, so don’t split the wood when hammered.

Small nails for small workpieces holding thin boards onto timber.

Flat screwCross type screw

Good for gluing Acrylic, plastics to wood timbers put pressure on both surfaces no chance of repositioning when dried.

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s Wastage:

Addition

Knock-down fittings.

This is waste which is produced when cutting wood. So sawing, planning, filing and sanding processes remove material giving waste. So to reduce the amount we waste careful planning is needed when cutting and reuse where possible.

Adds pieces of material together . Assembling parts, by making joints, gluing, screwing, nailing are called “Addition” processes. A fast method of making 3D shapes.

Range of block and fittings easy to use and fix a product together. Used in flat pack furniture, cupboards self assembly (IKEA)..

Key points to remember: The advantages and disadvantages of the different types of wood joints. The advantages and disadvantages of the different types of fixtures, fittings and hinges that can be

used.

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Ironmongery: This is the name given to parts that are brought to fit onto products: Hinges Handles Knobs Hooks Locks Drawer

runners

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Key points to remember: The advantages and disadvantages of the different finishes.

Surface finishes and treatments: Wood is porous which means it can absorb water and grease quickly look dirty and damaged. A surface finish fills the pores and makes it water resistant east to wipe clean. A finish will also make the product look better (aesthetics) of the wood.