UNIT 1.4 - COMPOSITES

Question 1

COMPOSITES

Answer 1

• A material comprised of two or more different materials, resulting in a material with enhanced properties

Question 2

MANUFACTURED BOARD

Answer 2

• A man-made wood based composite material

Question 3

CARBON FIBRE REINFORCED PLASTIC (CFRP)

Carbon fibres mixed with polyester resin

Answer 3

PROS: lightweight/corrosion resistant/tough/hard/good compressive strength/low thermal expansion
CONS: expensive/conducts heat and electricity - depends whether you want that
USES: sports equipment/bike frames/tennis racquets/fishing rods/racing car bodies/helmet/prosthetics

Question 4

GLASS REINFORCED PLASTIC (GRP)

Glass fibres mixed with polyester resin

Answer 4

PROS: lightweight/corrosion resistant/tough/hard/low thermal expansion/good compressive strength
CONS: expensive/uv can cause fading over the years
USES: boat hulls/pond liners/kayak shells/sports car bodies/locomotive train cabs

Question 5

MEDIUM DENSITY FIBREBOARD (MDF)

Compressed wood fibres (sometimes urea formaldehyde is added as an additional resin)

Answer 5

PROS: two smooth faces/available in either standard grade or veneered with a layer of timber/good strength in all directions/easy to cut and shape
CONS: easy to damage/heavier/weaker than wood/can crack or split under compressive strength/absorbs water quickly
USES: model or mould making/bookcases/cabinets/desks/flat pack furniture

Question 6

HARDBOARD

Compressed wood fibres

Answer 6

PROS: one hard and shiny smooth surface/doesn’t split easily/tough
CONS: no natural grain/not waterproof/heavy
USES: furniture inserts such as wardrobe backings/drawer bases/peg boards/clipboards

Question 7

CHIPBOARD

Wood chops compressed with a resin such as urea formaldehyde

Answer 7

PROS: good strength in all directions/easy to cut/cheap/lightweight
CONS: can chip on a cut edge/not generally attractive in basic form/not moisture resistant
USES: often veneered or covered with polymer laminate/kitchen worktop and units/shelving/flat pack

Question 8

PLYWOOD
Thin layers of wood are placed at 90 degrees to each other and compressed (sometimes urea formaldehyde is added as an additional resin)

Answer 8

PROS: good strength in all directions/no grain weakness/always has an odd number of layers/tough
CONS: difficult to cut and mould/expands, warps and distorts when exposed to liquid/brittle - can’t take nails well
USES: structural work/desktops/indoor furniture/floorboards