Wood - Performace Charcteristics Flashcards
(50 cards)
1
Q
What is meant by rough sawn ?
A
- wood comes directly from seasoning
- has rough edges
- have nominal sizes rather than accurate finished sizes and is the cheapest to purchase
2
Q
What is meant by planed square edge ( PSE ) ?
A
Wood that has only one edge planned , other sides would be rough sawn
3
Q
How much material does planning remove from the original nominal size ?
A
3mm from the edge
4
Q
What is meant by planed all round ?
A
Wood has sides and edges that are all planes square, straight and level , leaving a smooth finish
5
Q
What is meant by natural wood ?
A
- wood that comes from trees and is only available at the maximum width of the tree
6
Q
How should wooden planks be joined ?
A
- with the end grain in opposite directions to minimize distortion
7
Q
Characteristics of wood ?
A
- a natural material that will naturally biodegrade when left in landfill
- expands and shrinks with changes in humidity
8
Q
Describe wood fibres ?
A
- consist of hollow cells supported by lignin
9
Q
What direction is wood strong in ?
A
- in the direction along the grain ( weaker across the grain
10
Q
How much water content is removed when wood is seasoned ?
A
80 to 90 percent
11
Q
How are seasoned woods suitable for manufacturing?
A
- prevent defects such as warping , cupping , cracking or bowling
- less corrosive to metals
12
Q
When should trees be felled to reduce the time taken to season and why ?
A
- during the winter when they grow less and have less sap
13
Q
What is air seasoning ?
A
- a tradional and inexpensive method
- wood is stacked in a shelter outdoors and protected from the rain
- air circulated to remove mostiure
- take up to a year
14
Q
What type of product is air seasoned woods used for ?
A
- outdoor products
15
Q
What is kiln seasoning ?
A
- expensive , uses controlled temperature and humidity levels
- wood is stacked on trolleys
- it is initially steamy in the kiln then it becomes hotter and drier
- few weeks for processing
16
Q
What are benefits of seasoned woods ?
A
- greater immunity from decay and increases resistance to rot
- increased stability and strength
- helps preservatives to penetrate
- makes wood less corrosive to metals
17
Q
What are the soft woods trees ?
A
- redwood
- spruce
- pine
- larch
- cedar
- Douglas fir
18
Q
What are the hardwoods ?
A
- oak
- mahogany
- ash
- teak
- beech
- birch
19
Q
Properties of pine
A
- straight grain
- readily available
- knotty ( weaken the wooden when the fall )
20
Q
Uses of pine ?
A
- construction and low cost furniture
21
Q
Properties of larch ?
A
- tough and hard
- attractive grain pattern
- fades to silver upon outdoor exposure
22
Q
Uses of larch ?
A
- garden furniture and cladding
- decking
23
Q
Properties of spruce ?
A
- straight grain , resistant to splitting
- good strength to weight ratio
24
Q
Uses of spruce ?
A
- guitar bodies and indoor furniture
25
Properies of Douglas fir ?
- straight / slightly wavy grain
- knotty
- stable
- good corrosion resistance ( insect and rot )
- durable
26
Uses of Douglas fir
- veneers
- joinery
- flooring
- doors
27
Properties of redwood ?
- rich colour
- strong
- durable
- weather and insect resistant
28
Uses of redwood ?
- decking , garden furniture
29
Properties of cedar ?
- good sound damping
- rot and insect resistant
- low density
- straight grain
30
Uses of cedar ?
- exterior cladding
- sheds
- green houses
- interior panelling
31
Why are straight grains good properties ?
- less likely to split under stress
- stronger in tension and bending
- ideal for load bearing
- easy to work with ( cuts / planes and sands
- shrinks evenly with changes in moisture
32
Properies of oak wood ?
- tough
- durable
- attractive grain
- good weather resistance
33
What is a negative if oak ?
Contains tannic acid - which corrodes steel crews or fixings
34
Uses of oak ?
Furniture and flooring
35
Properties of ash ?
- tough
- attractive open grain pattern
- open grain makes it more flexible
- shock absorbing
36
Uses of ash ?
- tool handles
- ladders
- sports
- laminating
37
Properties of mahogany ?
- durable
- rich dark colour
- interlocking grains that make it hard to work with
38
Uses of mahogany ?
- furniture and veneers
39
Properties of beech ?
- close grained ( dosent dent easily ) / hygienic
- can be bent with steam
- hard
40
Uses of beech ?
Kids toys and chairs and kitchen products
41
Properties of teak ?
Very hard
- close grain ( minimal warping )
- naturally water resistant ( full of oils )
- rot and insect attack resistant
- heavy
42
Uses of teak ?
- outdoor furniture and benches
43
Properties of birch ?
- elastics and tough
- readily available
- hard
44
Uses of birch ?
- plywood construction
45
Properties/ characteristics of ply wood ?
- thin layers of wood placed 90 degrees to one another and compressed
- good strength in all directions
- no grain weakness
- odd number of layers
46
Properties and characteristics of marine plywood ?
- similar construction to plywood but gap and void free
- water and boil proof glue is used to make it resist water
- resistant to fungal attack
47
What are the properties and characteristics of aeroply ?
- high quality timber such as birch
- thin sheets
- easy to bend around a support frame
48
Properties of flexible plywood ?
- sheet can flex due to open grain on outer layers ( bent and glued around former )
- odd number of sheets
49
Properties of chipboard ?
- wood chips compressed with resin
- veneered on the surface
- very cheap
50
Properties of mdf ?
- smooth even surface
- easily machined
- can be laminated or have a veneer added
