Metals are arranged into two groups:
Ferrous metals- metals that contain iron and carbon. These metals will rust. (oxegenize)
Non ferrous metals- Metals that do not contain iron. These metals do not rust.
Ferrous metals:
Mild steel: Quite string and cheap but rusts easily and can't be hardened or tempered.
High carbon steel: Harder than mild steel and can be hardened.
Cast iron: Hard however brittle under impact.
Non ferrous metals:
Aluminium: Lightweight and corosion resistant. Exspensive and not nearly as strong as steel.
Brass- quite strong, corosion resistant maileable, ductile and looks good.
Copper- Relatively soft malleable and ductile and a very good conductor of electricity.
Most metals come from ores.
Steel: Mixture of iron and carbon.
Carbon: Comes from organic materials such as coal and diamonds.
Metal processes:
Sand casting: The process involves pouring molten metal into a prepared cavity in a sand mould and allowing it to solidify, steel and aluminium are the most common metals cast.
Gravity die casting: Mazak an alloy of Zinc and aluminium is first melted in a crucible furnace. Molten metal is then poured by ladle onto a open steel mould where it is allowed to cool and soloidify. The mould is then turned upside down and topped with a hammer to release the finished casting. Gravity die casting required minimal finishing and waste is minimal because excess metal can simply be melted down and used again.
Thursday 8 October 2009
Monday 5 October 2009
Theory main notes!
Lumber has been felled. Still in it's log form.
Wood is the material
Tiber is the processed material
Hardwoods- Dicidious trees, loose there leaves in the winter
(Ash, Oak, Beech, Teak, Walnut)
Slow growing
Softwoods come from the coniferous trees with needles and cones, evergreens
(larch, spruce, scots pine, douglas fur)
Fast growing
Softwoods are cheaper to buy due to it being able to groq quicker, it is a more sustainable source that hardwoods.
The age if a tree can be found by counting the amount of anual rings.
The dark rings show the winter months and light rings show the summer. The thickness of the rings show how long the summer or winter was. The rings are lighter in the summer as less resin is needed tp protect the tree as it is not that cold.
FSC symbol is placed on any wood that comes from a sustainable source for every tree that is vut down they will plant two.
Natural woods: Wood is fiberous with fibres running along the length of the trunk.
55% of the tree is cellulose
28% lignin resin this holds the structure of the tree together.
Timber is a natural fibre reinforced polymer.
Processing timber:
The process: 1.) Harvesting- cuttind down the trees.
2.) Conversion-cutting the trunk and large branches into boards. Slab sawn of quarter sawn.
3.) Seasoning-reducing the moisture content of the timber.
4.) Board preparation-Sawing to size and planning
Seasoning two types. Natural seasoning
Kiln seasoning
Quarter sawn timber: Most commonly used on exspensive hardwoods.
MORE waste - MORE stable - LESS liable to warp and twist - often exposes more attractive grain structures.
Timber shrinks most along the annual rings.
Edge jointing opposite annual rings used to add structure and stability to the wide board to stop it bending.
Finishes: Finishes are used to protect and make timber water tight so that moisture can not enter the timber.
Wood stain: used to dye or stain the material.
Oils: Furniture based, rubbed in to protect and enhace the colour of the timber.
Preservaties: Timber is kiln dried and then before it is sent out is injected by tanelised that soaks in 5mm. This timber does not need any other types of finish as the injection is good enough. Mainly for exterior use.
Paint: Must be primed before application to seal the timber.
Manufactured boards:
Cheap to buy, good use of recycled materials. No moisture or any irregularities so the board will not move in any way.
MDF: Medium fibre density fibre boards. Very small wood chippings and pva glue.
Plywood: Made by veneers of timber with each grain layer being at right angles to the other to add stability and strength.
Chip board: Wood chippings glued together, normally used in worktops and vannered to add aesthetic appeal.
Hardboard: Very fibreous easy to break. Used as backings to wardrobes.
Block board: Square sections of timber the glued together. Sometimes a venner on top.
comes in multiples of 3 (3,6,9,12,15,18,21,24)mm by 1,120 mm.
Flexi ply: Machined with grooves in the back so that it can be molded over a mould to create a shape.
Aeroply: Very posh plywood, can be manipulated and moulded. Can be used as the shapes to aeroplane wings.
Maplex: New type of MDF, very high density and chep. Used in the furniture industry.
Wood is the material
Tiber is the processed material
Hardwoods- Dicidious trees, loose there leaves in the winter
(Ash, Oak, Beech, Teak, Walnut)
Slow growing
Softwoods come from the coniferous trees with needles and cones, evergreens
(larch, spruce, scots pine, douglas fur)
Fast growing
Softwoods are cheaper to buy due to it being able to groq quicker, it is a more sustainable source that hardwoods.
The age if a tree can be found by counting the amount of anual rings.
The dark rings show the winter months and light rings show the summer. The thickness of the rings show how long the summer or winter was. The rings are lighter in the summer as less resin is needed tp protect the tree as it is not that cold.
FSC symbol is placed on any wood that comes from a sustainable source for every tree that is vut down they will plant two.
Natural woods: Wood is fiberous with fibres running along the length of the trunk.
55% of the tree is cellulose
28% lignin resin this holds the structure of the tree together.
Timber is a natural fibre reinforced polymer.
Processing timber:
The process: 1.) Harvesting- cuttind down the trees.
2.) Conversion-cutting the trunk and large branches into boards. Slab sawn of quarter sawn.
3.) Seasoning-reducing the moisture content of the timber.
4.) Board preparation-Sawing to size and planning
Seasoning two types. Natural seasoning
Kiln seasoning
Quarter sawn timber: Most commonly used on exspensive hardwoods.
MORE waste - MORE stable - LESS liable to warp and twist - often exposes more attractive grain structures.
Timber shrinks most along the annual rings.
Edge jointing opposite annual rings used to add structure and stability to the wide board to stop it bending.
Finishes: Finishes are used to protect and make timber water tight so that moisture can not enter the timber.
Wood stain: used to dye or stain the material.
Oils: Furniture based, rubbed in to protect and enhace the colour of the timber.
Preservaties: Timber is kiln dried and then before it is sent out is injected by tanelised that soaks in 5mm. This timber does not need any other types of finish as the injection is good enough. Mainly for exterior use.
Paint: Must be primed before application to seal the timber.
Manufactured boards:
Cheap to buy, good use of recycled materials. No moisture or any irregularities so the board will not move in any way.
MDF: Medium fibre density fibre boards. Very small wood chippings and pva glue.
Plywood: Made by veneers of timber with each grain layer being at right angles to the other to add stability and strength.
Chip board: Wood chippings glued together, normally used in worktops and vannered to add aesthetic appeal.
Hardboard: Very fibreous easy to break. Used as backings to wardrobes.
Block board: Square sections of timber the glued together. Sometimes a venner on top.
comes in multiples of 3 (3,6,9,12,15,18,21,24)mm by 1,120 mm.
Flexi ply: Machined with grooves in the back so that it can be molded over a mould to create a shape.
Aeroply: Very posh plywood, can be manipulated and moulded. Can be used as the shapes to aeroplane wings.
Maplex: New type of MDF, very high density and chep. Used in the furniture industry.
Thursday 1 October 2009
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