DT Flashcards
BLOCKBOARD
This is built up with a core of softwood strips bonded together with adhesive and covered with a sheet of plywood on either side.
CHIPBOARD
- This is made up of small chips of wood bonded together with resin and formed into sheets by compression.
- It is not as strong as plywood and block board but it is not expensive.
HARDBOARD
This is made from wood fibers that have been pulped.
It is not as strong as the other boards.
MEDIUM DENSITY FIBRE BOARD (MDF)
A quality board, relatively cheap. This board is composed of fine wood dust and resin pressed into a board. This material can be worked, shaped and machined easily. Paint can be applied to it without the need for an undercoat or primer. Used in the building and furniture trades.
PLYWOOD
This is made from veneers (plies) of timber with each grain layer being at right angles to each other and bonded together by resin and pressure.
PINE
Is a relatively cheap wood used in the building trade and for furniture. It is pale in colour, quite easy to cut and shape, and machines relatively well.
MAHOGANY
Is quite expensive and is used for good quality furniture and hardwood windows. It is light brown in colour and more difficult to use compared to pine.
OAK
- This is an expensive material and is used in for making quality, expensive furniture.
- Steel fittings such as hinges will stain oak so it is important to use brass ones.
TEAK
A hardwood that contains oils which means it is resistant to decay. This is often used to make garden furniture or for wood block flooring.
Mild Steel
Tough. High tensile strength. Can be case hardened. Rusts very easily.
Carbon Steel
Tough. Can be hardened and tempered.
Stainless steel
Iron, nickel and chromium.
Tough, resistant to rust and stains.
Cast iron
Strong but brittle. Compressive strength very high.
Wrought iron
Fibrous, tough, ductile, resistant to rusting.
Aluminium
Ductile, soft, malleable, machines well. Very light.
Copper
Reddish brown
Not an alloy
Ductile. Conducts electricity and heat.
Brass
Yellow
Hard. Casts and machines well. Surface tarnishes. Conducts electricity.
Silver
Whitish grey
Mainly silver but alloyed with copper to give sterling silver.
Ductile, Malleable, solders, resists corrosion.
Lead
Bluish grey
Not an alloy.
Soft, heavy, ductile
Thermosetting plastics
Once ‘set’ these plastics cannot be reheated to soften, shape and mould
Thermoplastics
These plastics can be re-heated and therefore shaped in various ways. They become mouldable after reheating
Styrofoam
This is a light-weight dense foam. It is easy to shape with saws, files and abrasive paper and is ideal as a model making material.
Nylon
Is used in engineering to make gears and bearings. It’s oily nature means that friction is reduced between moving parts made from nylon.
Acrylic
This is the most common plastic in a school workshop. It is purchased usually in the form of sheets and comes in a range of colours. It can be translucent (e.g. smoked), transparent or opaque. It is resistant to most acids and weather conditions.
Polythene
Can be moulded into almost any form due to its excellent moulding qualities. Used for the production of bottles, bowls, toys, tube etc… It is available in large sheets. There are two types: High density which is rigid and hard, and low density which is tough and flexible.
Polyethylene
The most common plastic in everyday life. Used in the manufacture of ‘plastic’ bottles, grocery bags, shampoo bottles and children’s toys.
what is soldering? (definition and 1 use)
Soldering is a process, which is used when joining two metals by melting solder. Solder is a metal alloy usually made of tin. The iron is heated to temperatures above 400 degrees centigrade which then cools to create a strong electrical bond.
Commonly used when attaching components to a circuit.
soldering (steps)
- Place the component into the board, making sure it goes in the right way around and the part sits flat against the board.
- Bend the legs slightly to secure the part.
- Make sure the soldering iron has warmed up. If necessary use a brass soldering iron cleaner or damp sponge to clean the tip.
- Pick up the Soldering Iron in one hand, and the solder in the other hand.
- Place soldering iron tip on the pad.
- Feed a small amount of solder into the joint. The solder should melt on the pad and flow around the component leg.
- Remove the solder, then remove the soldering iron.
- Leave the joint to cool for a few seconds, then using a pair of cutters trim the excess component lead.
What type of shape should be formed if you have used the correct amount of solder on the joint?
A cone shape.
Pewter casting (definition and 1 use)
Pewter casting is the process of melting down pewter to it’s liquid form and pouring it into a mould. To form a metal object in the shape of the chosen mould.
It is commonly used when making necklaces or pendents.
Pewter casting (steps)
- Before casting can take place a mould must be made. Moulds can be made from a range of materials including MDF, steel, silica sand or even oil based casting sands such as ‘petrabond’
- The raw materials (tin [96%] and copper [4%]) are cut up and heated to 350° in a kiln.
- Very quickly a molten liquid is formed, which, using a casting ladle, is poured into mould with extreme care.
- Then mould is then left to cool whilst still being clamped together.
- Once cooled, the pewter should be removed from the mould and finishing touches should be added using a file or wet and dry paper.
What are the 6R’s of sustainability?
- Reuse
- Reduce
- Recycle
- Rethink
- Refuse
- Repair
what does ACCESSFM stand for?
- aesthetics
- consumer
- cost
- environment
- size
- safety
- function
- materials
