Metals

Ferrous metals

• contain iron
• prone to rusting
• magnetic

Non - ferous Metals

• do not contain iron
• do not rust
• not magnetic
• more expensive

Alloys

• 2 or more metals mixed togther
• or a metal combined with a different material
• ehance the properties by combining more than one metal

Alloys can be used to:

• change the colour
• change the strength
• change the electrical conductivity

Most metals become less hard and more ductile when they are heated

Work Hardening

• the more the metals are worked and processed, the harder it becomes to work with them

Annealing

• is the process of heating the metal until it is cherry red, making it easier to work with

Hardening

• is the process of heating the metal to cherry red then rapidly cooling it, in water, for example.
• the rapid cooling is know as 'quenching'
• mainly used for carbon steel

Tempering

• often done after hardening
• apply heat, then quench
• leaves a grey coloured coating toughening the metal and preventing it from being brittle

What I know about Wood and Manufactured Boards

Wood

Timber is avaliable in different forms.

There are hardwoods, softwoods or manufactered boards.

Hardwoods come from decidious trees, they shed their leaves each autumn. They tend to bear fruit and are very slow growing. This makes them more expensive and slower to manufacture.

Softwoods come from evergreen trees, they don't shed their leaves at all. They often have fir cones and grow much faster. They are lots cheaper and readily avaliable.

Manufactured boards

Plywood - Skateboards, chairs

• Layers of wood (plys) put on top of each other with the grain at right angles to the previous ply
• generally stronger due to this
• often laminated with beech
• lightweight
• comes in different thicknesses

Chipboard - Tables, worktops

• Chips of wood and resin squashed into shape
• uses waste wood
• different thicknesses avaliable
• often laminated with melamine
• swells if it gets wet and goes out of shape

Sterling Board - Temporary boarding up

• large chips and resin squashed together
• weaker
• Cheap
• temporary

HardBoard - Bottom of drawers, back of wardrobes

• resin and fibres pressed into sheets
• less fibres than MDF
• weak
• has a rough side and a smooth side
• stronger than cardboard but weaker than most manufactured boards

MDF (Medium Density Fibreboard) - Worktops, cheap furniture

• Resin and fibres pressed into sheets
• Urea Formaldehyde is the resin used to bond fibres
• dangerous when cut or sanded - dust cells hook onto lungs or into eyes
• mask and goggles should be worn if being worked with often

Blockboard - Shelves

• Strips of wood stips placed side by side
• heavier
• can splinter
• gaps between strips/layers
• rougher finish
• stronger than plywood but not as nice

Hexaboard - temporary flooring

• embossed with hexagon shaped tred
• grippy
• strong
• temporary

I should never have bought

I recently bought a 'lunch cube' from sistema as I thought that it was a practical and useful design and had wanted one for a while. The cube consists of separate compartments, designed to hold individual pieces of fruit and a sandwich, without being squashed or next to another lunch box item.

I thought it was a fairly reasonable price at £3.50 but compared to a normal, rectangular box, it seems slightly overpriced. A rectangular box would have been a better buy as it would not have all the problems that I came across.

I was disappointed when I came to using the cube as I found I could not fit much in there. The section for sandwiches is barely wide enough for an average sandwich and rolls have to be squashed to fit. It will not even close fully when one is in there. I thought that the other sections may be better but I found that I was unable to fit a small apple in the either compartment, as the sections were not tall enough. The slightly larger section would not fit a packet of crisps or a banana but was too large for a cereal bar. I resorted to cutting my apple in half and wrapping it in foil, which is impractical and wasteful.

I thought that by using the 'lunch cube' I would minimise the time spent packing my lunch and also prevent my items from being squashed. I seem to spend more time attempting to use the space logically and all my items have to be squashed to fit in the cube, defeating the purpose of the box.

As it has all the individual sections, it is also quite difficult to wash by hand and it is hard to position it suitably in a dishwasher, without using too much space.

I have kept the lunch cube because I don't feel able to get rid of it yet, especially as I had praised the design and planned for one for a while before buying one but I would not advise people to buy a lunch cube unless they are prepared to change the contents of their lunch box and eat squashed sandwiches from now on.