Woods Flashcards
What is timber?
raw material - tree is:
1. cut down
2. felled in to logs
3. cut into planks
What are hardwoods?
deciduous:
- grow slowly (not in winter) - 100-500 years = non renewable
- expensive
- stronger
- aesthetics (due to grain)
- more durable
- heavy
- small warp
- hard to cut
What are examples of hardwoods?
birch
beech - tight grain prevents entry of moisture, so no decay, fungi growth ect)
elm
oak
teak / mahogany - (EXOTIC) weatherproof
spruce
jelutong
What are general uses of harwoods?
high quality furniture (indoor and outdoor)
flooring / decking (for boat)
handles
Why should exotic hardwoods (especially) not be cut?
in rainforest, causes habitat loss, disrupt ecosystem, reduce biodiversity, umbrella for humidity and shade
What are softwoods?
coniferous (evergreen):
- grow quickly (all-year round) - 10-50 years = renewable
- cheaper
- weaker
- less durable
- lighter
- large warp
- easier to cut
What are examples of softwoods?
redwood
cedar
larch - more durable, decay resistant - yacht making
yew
pine
What are general uses of softwoods?
outdoor structures (shed, fence posts)
joinery
construction framing
How can softwoods be grown sustainably?
dividing forest into acre segments, cut one square per year then replant, after cutting each segment the first will be ready to cut again
How can timber be bought?
in stock sizes:
sheet
board
plank
strip
square
dowel
Why are stock sizes important?
so wood can be made and bought cheaper:
consistently made in standard sizes, with the knowledge it will be bought
What is seasoning?
prevents deformation
- warp
- bow
- twist
- split
by removing 80% of moisture, under heat and pressure
What is industrial seasoning?
place in massive kiln (hot oven)
3-5 months
low cost
lower quality
What is natural seasoning?
roof over top, ‘shelves’ with space between each plank, air and sunlight dry it out
3-5 years
high cost
higher quality
What are environmental impacts of cutting down trees?
stop filtering CO2 from air:
- climate change
- cause desertification
- habitat loss = less biodiversity = kill wildlife
What are manufactured boards?
man-made composite -
less durable
no grain = no warp
easy to cut
very cheap
What are manufactured boards?
man-made composite - timber waste and glue
sustainable, but can’t recycle
less durable
no grain = no warp
easy to cut
very cheap
What are examples of manufactured boards (and uses)?
hardboard
MDF
chipboard
sterling board
blockboard - work surfaces
plywood
What are uses of hardboard?
sawdust / wood pulp
underside of drawers, back of picture frames
What are uses of MDF?
sawdust
good with laser cutter
smooth surface paints well
cabinet doors (kitchen)
What are uses of chipboard?
small wood chips
high compressive strength
VENEERED flat pack furniture / kitchen table top
What are uses of sterling board?
large wood chips
VERY strong
construction - in place of windows
What are uses of blockboard?
blocks/corners - excess from trunk
school desk, work surfaces
What are uses of plywood?
grain of each layer glued at 90º to previous = high cross sectional stability (sheets are laminated)
large work surface, flat pack furniture
What is marine ply?
tropical hardwood
boats and interiors
What is aero ply?
birch/tropical hardwood
aircraft interiors
What is flexi ply?
talk about vacuum pressing and laminating
grain always in same direction
furniture
vacuum pressing:
1. one-sided former (block made to hold material in required shape) used with vacuum bag
2. connected to pump which removes air
3. outside pressure holds veneers in place as glue dries
OR laminated:
1. stacked with adhesive between
2. clamped under pressure
3. glue sets and wood is removed (retains shape of mould)
What is an ecological wood?
bamboo, grass that grows quickly (three years –> grow to replace what is cut down) flexible, lightweight, very strong
