Woods Flashcards
What is a common use for mouldings made from wood?
Skirting boards or wooden trims
These mouldings are readily available in standard lengths.
What is one reason why manufactured boards are preferred over solid wood?
They are generally less affected by temperature and humidity
This stability makes them suitable for various applications.
What are the qualities of spruce wood ?
-hard
- good strength to weight ratio
- not very durable
- very knotty
What type of wood is used to manufacture musical instruments and why?
Spruce wood , as it has a good resonance producing a pleasant sound
What are the qualities of Douglas fir wood ?
- high quality wood
- harder than regular soft woods
- durable
- resistant to rot and insect attacks
What are the uses of Douglas fir wood ?
- doors
- flooring
- windows
What are the qualities of redwood ?
- rich colour (making it popular )
- durable
- strong
- weather and insect resistant
What are the uses of redwood ?
- decking
- outdoor furniture
- fences
What are the qualities of cedar wood ?
- high oil content (making it resistant to decay to moisture, weathering , insect attack )
- straight grain (less chance of warping )
-less inconsistency (knots ) - good sound damping
- low density making it lightweight
What are the uses of cedar ?
- exterior cladding
- sheds
- interior panelling
What are the qualities of pine wood ?
- inexpensive
- strong
- straight grain
- very knotty (tends to fall out posing challenges whilst manufacturing
Uses of pine wood ?
Low cost furniture and fencing as well as construction
What are the qualities of larch wood ?
- tough
- durable
- resistant to rot as a result of its high resign content
Which soft wood has a high resign content ?
Larch wood
Which softwood has a high oil content ?
Cedar
What are the different soft woods ?
Cedar / spruce / Pine / Larch / redwood / Douglas fir
In which direction would the would tend to split in ?
Working across the grain would result in the wood splitting.
What does planning the wood along the grain keep the wood from doing ?
Splitting / tearing
How is the pattern in the grain created ?
Every season the tree would produce a new ring
Do knots affect the performance ?
It tends to weaken the wood and it sometimes may fall out producing a hole.
What is the wood structure like ?
Wood fibres are made from hollow straw like cells which are held in lignin. These make the wood strong along its length
What are the straw like cells within the wood called ?
Tracheid
What is the function of tracheid within the structure of the wood ?
Carry water and nutrients to and from the roots to the leaves
What is a pro of using manufactured boards instead of natural woods in terms of surface defects ?
Manufactured boards are uniform in their surface finish whereas natural woods are much less predictable
What are the possible surface defects that natural wood may consist of ?
- knots (may fall out as the wood shrinks
- machining can produce marks on the timber from saw mills
- woods can be damaged by insect attack and rot
What do surface defects of the wood affect ?
Surface defects such as knots can affect the stability of the wood
Once the timber is felled what process must it go through ?
Seasoning
Why must timber be seasoned once felled ?
To prevent distortions such as twisting / cupping/warping/ bowling and split
Wood acts as a sponge and absorbs moisture and swells when placed in damp conditions. What is the technical name given for this ?
Hygroscopic
What are the different ways that wood can be seasoned ?
Air dried / kiln dried
What process do air dried wood go through ?
Planks are stored under cover and left to dry naturally
What process do kiln dried wood go through ?
Steam is used to artificially dry the timber and speed up the drying process
What process do kiln dried wood go through ?
Steam is used to artificially dry the timber and speed up the drying process
What happens to the wood in exposure to different levels of moisture as well as the seasons in any given environment?
The wood tend to swell and shrink
Where does most shrinkage occur ?
It occurs around the year rings
What is the percentage of radial shrinkage ?
2-8%
What are the working properties of seasoned woods ?
- stronger and much more stable
- less likely to decay and rot
- it is less likely to corrode metals
- absorbs preservatives more readily