Flashcards in Woods Deck (21)
What is conversion?
When a tree is cut into rough sawn planks (green timber)
What is the best pieces of wood from a log?
Pieces with a good grain structure, when the grain is going down the plank.
How would you cut wood cheaply and quickly but not get high quality wood?
You would cut the wood down the log however this would make imperfect grain structures.
How would you cut wood to make would with a good grain structure?
You would quartersaw the wood. This cuts out planks which all face towards the center of the log so they have a good grain structure. However this is expensive and slow.
What is seasoning?
Is the turning of rough sawn plank (green timber) into EMC-equilibrium moisture content (dried to suit surroundings). It will always have a square edge.
Why is green timber not usable apart from which exception?
Green timber is flexible so not great for building things however oak can be used in its green state.
What is air-dying and what is its problems?
Air-drying can reduce the moisture in the wood to 20% in a covered shed. This takes 6 months-1 year which is inconvenient and it is exposed to the elements so insects can destroy the wood.
What is kiln-dying?
Kiln-dying can reduce the moisture in the wood to 10% in an autoclave (oven). It takes 2-5days.
What is a soft wood?
Soft wood is wood from a coniferous (cone bearing) tree. Like pine.
Give some positives (3) and some negatives (3) of Scots Pine and examples of it in use (2).
+ Fast growing
+ Usable within 40yrs
Used in moulds/jigs and and for builders construction.
Give some positives (3) of Spruce and examples of it in use (2).
+ Fewer knots than Scots pine
+ Ling fibers
Used in high quality paper (long fibers) and interior wood work like doors and skirting boards.
Give some positives (2) of Douglas fir and examples of it in use (3).
+ Not many knots
Used in flooring, furniture and window frames.
What does a wood having an FSC stamp mean?
More trees are planted than are cut down.
What is a hardwood?
Broad leaved and not cone bearing trees.
Give some positives (5) and some negatives (2) of Beech and examples of it in use (3).
+ Non abrasive
+ Short grain, almost knot free
- Bland/dull appearance
- Takes 80yrs to grow
Used in kitchen products, flooring and furniture.
Give some positives (5) and some negatives (2) of Oak and examples of it in use (1).
+ Long grained - rigid
- Very abrasive
- Takes 90yrs to grow
Give some positives (3) and some negatives (1) of Mahogany and examples of it in use (2).
+ Very dense
+ Hard to damage
- Not FSC
Laboratory and bar tops.
Give some positives (1) and some negatives (1) of Teak and examples of it in use (1).
+ Lasts 50yrs with no treatment outside then treated to last another 50yrs.
What are some properties of man made woods?
Dimensionally accurate - constant thickness and stable
Available in large sizes
Not necessarily cheap - plywood is more expensive than solid wood.
Give some positives (4) of MDF and examples of it in use (3). What is it made from?
+ Made from unusable wood dust
+ Very dense
+ Very strong
Used for vacuum forming (as has no grain), model making and table tops (but needs covering).