1 Materials and processes- composites

Question 1

composites

Answer 1

glass-reinforced plastic

carbon fibre

medium density fibreboard

hardboard

chipboard

plywood

Question 2

Glass-reinforced plastic

Answer 2

applications 
Rotor blades of wind
turbines, canoes, fish
ponds, vehicle bodies,
kiddies sit 'n' ride and
fairground rides, etc.

advantages
 Excellent strength to weight ratio
 Resistant to corrosion and water
 Ideal for external shell structures
 Wide range of colours
 Can be repaired easily 

Disadvantages
 Expensive material
 The specialised manufacturing process required
 High-quality mould needed

Question 3

Carbon fibre

Answer 3

applications
Tennis racquets and
fishing rods, bicycle
frames and wheels,
aircraft and vehicle
components, etc.

advantages 
 Excellent strength to weight ratio
 Better tensile strength than steel alloys
 Can be formed into complex and
aerodynamic one-piece structures

Disadvantages
 Very expensive material
 Only available in black
 Highly specialised manufacturing processes required
 Cannot be easily repaired as structure loses integrity
 Cannot be easily recycled.

Question 4

medium density fibreboard

Answer 4

applications
Flat-pack furniture,
general joinery work,
moulds for forming
processes, etc.

advantages 
 Less expensive than natural timbers
 Available in large sheet sizes and
range of thicknesses
 No grain, so no tendency to split
 Consistent strength in all directions

Disadvantages
 Heavier (the resins are heavy)
 Requires appropriate finishes to seal surface fibres
 Swells and breaks when waterlogged
 Warps or expands if not sealed
 Contains urea-formaldehyde – eye and lung irritant

Question 5

Hardboard

Answer 5

applications
Furniture components,
wall panelling,
moulded door skins.

advantages 
 A number of specially hardboards are
available for specific purposes. These
have either embossed, perforated,
plastic-faced or veneer surfaces.

Disadvantages
 Hardboard cannot be used outside because it absorbs
water

Question 6

chipboard

Answer 6

applications
It is often used for
kitchen tops (laminated
with melamine) and
fire doors.

advantages 
 Reasonably priced
 Durable
 Looks Like Wood
 Environmentally Friendly - It is made
from recycled materials

Disadvantages
 Tend to soak up water.

Question 7

plywood

Answer 7

applications
Wall panelling, flooring
and furniture. Marine
Plywood can be used
underwater.

advantages
 Strength and durability
 Available in large sheets

Disadvantages
 Susceptible to water damage if exposed to leaks over
time.