Timber Flashcards
What are the key features of softwood?
-comes from coniferous
-grows faster than hardwoods making it cheaper
-easy to with, often used as a building material
-relatively renewable
-have needles instead of leaves
-it grows tall and straight making it easier to manufacturer which can be cut long and straight planks of wood
Name 3 examples of softwood, and there use.
Scots pine (fences, box), Parana pine spruce, yellow cedar(poles), European redwood (beams)
What are the key features of hardwood?
-come from deciduous or board-leafed trees
-they are special as the are deciduous meaning they lose their leaves in the autumn/winter months
-they grow slower than softwoods making them more expensive
-strong wood density
Name 3 examples of hardwood, and there use.
beech (children toy), oak (good for building), mahogany, teak (ship building), balsa
What are the two types of seasoning
Natural, kiln
Define seasoning
removal of excess moisture for newly swan timber
What is kiln seasoning?
-it is like factory process
-steam, heat and fan can control the moisture
Give a pro and a con for kiln seasoning
Pro:
-accurate water content achieved
-12% or lower moisture content achievable-controllable
-kills bugs and fungus
-fast
Con:
-expensive
What is natural seasoning?
-timber is seasoned by subjecting it to the natural elements such as air or water
Give a pro and con for natural seasoning?
Pro:
-cheap
-some say the timber is stronger than kiln-seasoned
Con:
-very slow (a year per inch thicknes）
-bugs and fungus survive
-water content is hard to control accurately
-end of planks can split
What is timber defect?
any irregularity occurring in or on the wood that lowers its strength durability utility value or appearance
What is warping?
this can occur when the timer is not stored flat. If it is not laid flat, wood can become be bent or twisted
What is knot?
-a branch was attached to the tree
-live knots are ok and can be decorative
-dead knots need to be avoided
What is the problem of dry rot? How is it caused?
-serious problem— incorrect seasoning or poor building maintenance
-caused by timber being over 20% moisture content are not ventilated
Define woodworm
the common furniture beetle lays edges on timber. The larvae eat the wood for a year and then emerge as adult beetles in the spring. “Frass”, or wood dust is a sure sign of woodworm.
Explain the difference between steam bending and laminating
The process
What is FSC?
-global organisation to verify timber is sourced from ethical places
What is manufactured boards?
-comprise a range of sheet materials produced by pressing and bonding together wood particles, fibres or veneers to achieve particular characteristics - and to create a use for what would otherwise be discarded as waste
What are the advantages of manufactured boards?
Pro:
-available in large sizes and thickness
-designed for specific purposes, such as marine ply
-use waste from processing timber
-uniform - few imperfections
-do not split
-available in ready finished format - like veneers
Name 3 types of manufactured boards and the key features
Blockboard:
-softwood strip core
-bonded with adhesive
-covered with sheet of plywood
-finished with a veneer
Hardboard:
-pulped fibres pressured until fibres bond together
-smooth one side, rough on the other
-not as strong as other boards - cheaper
-used in non structural situations - backs of cupboards
Chipboard:
-small chips bonded with resin, compressed into sheets
-not as strong as ply or blockboard - much cheaper
-covered in a plastic veneer
-used in indoor furniture
Medium density chipboard (MDF):
-fine wood dust and resin pressed into a board
-worked easily
-strong (resin)
-used in lots of indoor applications
-easily finished/painted
Plywood:
-veneers of timber bonded by resin and pressure
-each at 90 degree to the other
-lots of sizes available
-can be manufactured for different purposes:
-flexi ply
-laser ply
-marine ply
