Unit 3

Question 1

What is a stock form

Answer 1

the standard shapes and sizes in which a material is available in

Question 2

What timbers are available in a range of stock forms

Answer 2

Rough sawn
Planed square edge (PSE)
Planed all round (PAR)

Question 3

What is the cheapest stock form timber and what is it used for

Answer 3

Rough sawn timber , surfaces are rough from industrial saws and is used commonly in construction

Question 4

what is planed timber

Answer 4

Planed timber is prepared using a planer and thicknesser. Material is wasted away, little by little, to achieve a 90° edge on one or more sides

Question 5

What does planing do

Answer 5

Makes the timber smaller and smoother

Question 6

PSE and PAR

Answer 6

PSE - one square edge
PAR - Square on all sides

Question 7

What are mouldings

Answer 7

They are machined profiles made for functional and aesthetic purposes
can be used on skirting boards

Question 8

how are manufactured boards sold and in what sizes

Answer 8

They are sold as half boards or full boards and the size of it is 1220 x 2440 mm but available in different thicknesses

Question 9

characteristics of softwoods

Answer 9

Fast growing low cost and long straight shape. They tend to be lightweight and require less time for seasoning

Question 10

types of softwoods

Answer 10

pine , douglas fir , cedar , spruce , redwood , larch

Question 11

pine

Answer 11

Pine is one of the most common woods used in furniture, internal joinery and wooden flooring. Pine is lightweight with a straight grain but has knots. can be used outdoor but needs to be treated first

Question 12

Spruce

Answer 12

Spruce, specifically Sitka Spruce, was widely used in the construction of aircraft in World War I and II. Easy to work with uniform texture

Question 13

Cedar

Answer 13

Cedar’s high oil content make it resistant to decay, moisture, weathering and insect attack. Lightweight, easy to work with and knot free but is fairly toxic which can cause respiratory, stomach and kidney problems. Used for boat building and outdoor panelling

Question 14

Larch

Answer 14

A hard timber with an attractive reddish brown colour which fades
to grey when exposed to sunlight. Larch has a high resin content
which can clog up cutting blades. Used for veneers as well as fence
posts, garden furniture and boats

Question 15

Douglas Fir

Answer 15

is one of the toughest woods . It’s cheap and strong which makes it suitable for large scale projects such as housing frameworks and cladding. Can be difficult to treat due to its density and high resin content

Question 16

What are characteristics of hardwoods

Answer 16

They are slow growing and need more land more expensive. dense and so are usually stronger and more durable
than softwoods

Question 17

Types of hardwood

Answer 17

Oak, Mahogany, birch, ash, teak, beech

Question 18

Oak

Answer 18

main engineering material for shipbuilding and architecture
Tough, durable and hardwearing, it’s also resistant to rot when
exposed to moisture.

Question 19

Ash

Answer 19

very springy hardwood with large open pores which gives it elastic qualities. Its elasticity makes it shock resistant, so it’s often used
in sports equipment and tool handles.

Question 20

Mahogany

Answer 20

many desirable aesthetic and working properties make it pricey
A highly-prized timber with excellent stability, workability and a beautiful grain. Trees are tall and stout so the timber is long,
wide and defect free – ideal for veneers

Question 21

Teak

Answer 21

naturally high in oils which make it ideal for outdoor products including furniture and boats. Considered the gold-standard in terms of decay resistance and durability, but its toxicity can spell trouble
Teak also has a high resistance to acids and alkalis

Question 22

Birch

Answer 22

fine grain which gives a uniform, even texture and makes it ideal for veneers. low-cost hardwood

Question 23

Beech

Answer 23

is hard, tough and odourless so it is resistant to abrasion and does not affect the taste of food. It has close, straight grain which makes it easy to work with. Similar to ash, beech is flexible and ideal for steam-bending

Question 24

plywood

Answer 24

strong in every direction and can’t split along the grain
Plywood uses lower grade hardwood and softwood veneers
It has a uniform, hard and smooth surface but you may notice patches and some knots on the surface

Question 25

aeroply and flexiply

Answer 25

flexiply are two materials which can be formed into curved shapes Aeroply was developed to form around frameworks to make aeroplane wings. Aeroply is made from several birch veneers Flexiply consists of a thin central veneer with two softer outers

Question 26

Chipboard and MDF

Answer 26

MDF is made from fine wood dust particles bonded with resin under pressure, where as chipboard uses larger chips. Neither are very resilient without surface treatment but their durability is improved with veneers or a hard-wearing paint

Question 27

Flat pack

Answer 27

MDF and chipboard are used extensively for manufacturing flat-pack furniture. Standardised components or “knock-down” fittings are used to enable quick assembly and disassembly of products

Question 28

What are some performance characteristics of wood

Answer 28

Grain pattern or direction , Warpage, shrinkage and splitting , Machining qualities , Resistance to decay and moisture , Toxicity

Question 29

What is the end grain

Answer 29

Pattern you see at the end of a piece of wood

Question 30

How is the structure of wood made or explained

Answer 30

Wood fibres are made from hollow straw-like cells (tracheid) which are held in a lignin Tracheid carry water and nutrients to and from the roots and leaves These straw-like cells make wood strong along its length

Question 31

What is an anisotropic material

Answer 31

The grain gives natural wood different physical properties in different directions

Question 32

Distortions

Answer 32

Must be seasoned , Wood is hygroscopic which means it behaves like a sponge – it absorbs moisture and swells up in damp conditions. As water evaporates wood shrinks

Question 33

How can wood be dried

Answer 33

Wood can be air-dried (AD) or kiln-dried (KD) Air-dried timber planks are stored under cover and left to dry naturally. Kiln-drying uses steam to artificially dry the timber and speed up the drying process

Question 34

How can wood shrink

Answer 34

With the seasons or the level of moisture called a stable timber if it doesn't

Question 35

Working properties of a stable timber

Answer 35

It is stronger and more stable, It is less likely to decay or rot, It is less likely to corrode metals It absorbs preservatives more readily

Question 36

What is forming

Answer 36

consists of both additive manufacturing and wasting processes as well as manipulation. Wasting processes like carving, turning, milling and routing are used to form woods

Question 37

What is steam bending

Answer 37

uses heat and moisture to make wood pliable

Question 38

What is laminating

Answer 38

combines wood and adhesives for different purposes. Laminating can be used to create curves using aeroply and flexiply . Natural wood boards are often joined using lamination to create larger, wider section

Question 39

Resistance to decay

Answer 39

In a dry and stable environment, free from insects and vermin, wood is extremely durable Many woods have a high oil content and so are less prone to decay and can be used outdoors without a preservative finish

Question 40

Insect attacks

Answer 40

Beetles and other insects, such as termites, are attracted to the starches and sugars in woods

Question 41

How do fungal attacks occur

Answer 41

Damp or poorly ventilated conditions make an ideal environment for fungal attack

Question 42

COSHH

Answer 42

Control of Substances Hazardous to Health

Question 43

How can woods be tested

Answer 43

tensile strength, toughness, hardness, corrosion malleability

Question 44

How can tensile strength be tested

Answer 44

Tensile strength can be tested by applying weight to a test piece and monitoring how much the material bends or deflects. A rule or Vernier callipers can be used to measure the deflection

Question 45

How can hardness be tested

Answer 45

You could hit a centre punch into a material and measure size of the dent created. Abrasive wear can be tested by running a file or some glass paper over the surface of materials and compare the number and depth of any scratches

Question 46

Toughness

Answer 46

To compare the toughness of different materials, hold each test piece in a vice and hit each one in turn with the same force The most brittle materials will snap and the toughest materials will absorb the impact

Question 47

Corrosion

Answer 47

It can rot and is prone to insect and fungal attacks. Leave outside certain amount of time and test the damage

Question 48

What is malleability

Answer 48

the ability of a material to be moulded without breaking. woods can be moulded using steam bending and laminating

Question 49

Tensile testing graph

Answer 49

Point A - ultimate elastic limit Point B - Yield limit Point C - Breaking point

Question 50

Janka hardness test

Answer 50

Janka test measures the ability of wood to resist scratches or dents. The test measures the average force needed to plunge a 0.44” or 11.28mm steel ball halfway into a piece of wood

Question 51

Non destructive testing

Answer 51

Non-destructive testing can detect faults in a material or product without causing any physical damage

Question 52

Ultrasonic testing

Answer 52

Ultrasonic testing detects internal defects using sound waves. Sound waves are pulsed into the material and the intensity of the reflected sound waves is recorded

Question 53

X-Ray testing

Answer 53

beams are passed through a material and project an image on to a film or screen

Question 54

Why is wood an excellent natural thermal insulator

Answer 54

Air pockets in cell structure

Question 55

How can wood working properties and aesthetics be enhanced

Answer 55

Combining wood with resins to create composite materials. Adding a preservative, finish or coating to timber to increase resistance to decay. Adding a laminate to improve the properties of the surface

Question 56

Preservatives

Answer 56

Preservatives can guard against insect and fungal attack, moisture, fire damage and rot as well as enhance aesthetics Pigments are added to give different colour options and improve aesthetics – this can make cheap materials look more expensive

Question 57

Glulam