Part 1 - Perfomence characteristics of woods Flashcards
rough sawn
The wood comes Direct from seasoning and has rough surfaces produced during initial conversion.
Rough sawn wood will have nominal sizes rather than actually finished sizes and is the cheapest stock form to buy.
Planed Square Edge (PSE)
Only one Edge that is planed accurately the rest is rough sawn.
planing removes about 3 millimetres from the original nominal size
planed all round (PAR)
Wood has sides and edges that are all planed Square straight and level leaving a smooth finish ready to use
Natural wood
Natural wood comes from trees and is available only at the maximum width of the tree. To produce a wide desktop natural wood plants need to be joined together
Manufactured boards
Man-made and produced in large sheets typically 1220 x 2440mm
Mouldings
Pre-made moulding such as skirting boards or wooden trims are readily available stand messed up to approximately 4 metres
Air Seasoning
What is stacked in a shelter outside protected from rain.
Air circulates between the planks to remove excess moisture
It is a slow process taking up to 1-year
The wood is used for Outdoor Products
kiln seasoning
The wood is stacked on trolleys
It is initially steamy in the kiln then becomes hotter and drier
It is a quick process taking up for a few weeks
The wood is used for indoor products
Seasoning wood
Gives immunity from decay and increase resistance to a rot
Increases strength and stability
Help preservatives to penetrate
Makes wood less corrosive to metals
Examples of hardwoods
oak - hard attractive grain good weather resistance. Contains tannic acid which would corrode steel screws or fixings.
Ash - Tough, attractive open grain pattern making it more flexible. Used for Tool handles, ladders, sports goods and laminating.
Mahogany - Rich, dark red colour. Indoor furniture, shop fittings and cabinets, often copied on veneers.
Birch - Hard, tough, straight grain, natural oils resist moisture, acids and alkalis.
Examples of softwoods
pine - straight grain knotty can contain resinous knots. Used for construction work roof beams and timber frae construction.
Spruce - straight grain resilient to splitting. Indoor furniture
Cedar - straight grain, can corrode ferrous metals due to acidic nature, low-density, good sound damping rot and insect resistant
Manufactured boards
Plywood - used for structural work, desktop, indoor furniture and floorboards. Made up of thin layers of wood placed at 90 degrees to one another and compressed to form the board.
Aeroply - used in gliders laminated furniture laser cut projects jewellery items.
Plywood made from high quality timber such as Bert available in a very thin sheet, lightweight, easy to bend around a support frame.
Chipboard - wood chips compressed with a resin such as urea formaldehyde.
Veneers or covered with polymer laminate kitchen worktops and unit shelving and flat pack furniture.
