GCSE Resistant Materials - Revision Flashcards
How do you mark timber
Pencil and Marking knife
How do you cut timber
Rip saw - rough cutting
Coping saw - curvaceous cuts
Tenon saw - straight lines with accuracy
How to clamp timber
G-clamps
What type of timber usually grows faster
Softwoods
How can you avoid timber warping
You can season it either naturally or artificially using a kiln
How does timber warp
When the moisture content of different parts of pieces of wood changes unevenly
6 R’s
Reduce
Reuse
Recycle
Rethink
Refuse
Repair
Softwood examples:
- Scots Pine - cheap, readily available, straight grains but prone to knots, strong, pale; low cost furniture, simple joinery
- Parana Pine - hard, fairly strong, straight grained and knot free, more expensive, pale yellow, darker brown streaks; better furniture, visible structural carpentry
- Spruce - not very hard wearing, creamy-white, small hard knots; indoor furniture
- Yellow Cedar - pale colour, light-weight, rigid; furniture, veneers, boat building
- Redwood - relatively strong, knots, low cost, durable when suitable clothing or treatment treats it; general woodwork, cupboards, shelves, roofs
Hardwood examples:
Ash - light creamy-brown, open grained; sports equipment wooden ladders, tools
Beech - white, close-grained, hard and strong, prone to warping; furniture, toys, tool handles
Elm - light brown, open grain, tough, resists splitting, water-resistant, durable outside; indoor + outdoor furniture
Mahogany - reddish-brown, interlocking grain, strong and durable; good quality furniture
Oak - light brown, strong, tough, open-grained, steel screws and fittings corroded, certain adhesive react with it; interior woodwork, high quality furniture
Manufactured boards:
Blockboard - softwood strips bonded together with adhesive, then sheet of plywood on either side, often with finishing veneer
Chipboard - small chips of wood bonded together with resin and compressed to form sheets. Cheaper but not as strong as plywood or blockboard
Hardboard - pulled wood fibres pressurised until fibres bond together, smooth on one side rough on the other, back of cupboards
MDF - very fine wood dust and resin, stronger than hardboard due to resin, easily finished with veneer/paint
Plywood - veneers of timber, grains at right angles, bonded by resin and pressure, different types :
- boil resistant plywood
- flexible plywood
- interior plywood
- laser plywood
- marine plywood
- weather and boil proof plywood
Advantages of Manufactured Boards over Natural Timber
- large sizes + standard sizes and thicknesses
- boards have specific purposes
- often use elements of waste, environmentally sympathetic
- uniform with few imperfections
- do not split
- ready finished formats
Timber finishes
Wax, French Polish, Varnish, Wood stain, Exterior wood stain, Oil, Paint, cellulose sealant
Plastic finish
Buffing Compound/ Polish
How do you measure timber’s lengths and angles
Ruler or Tape measure, Try Square, Mitre Square, Combination Square
How do you mark plastic
Permanent marker pen and odd-leg calipers
How do you measure plastic length and angles
Try, Mitre and combination square, dividers
How do you mark Metal
Straight steel edge and scriber and odd-leg calipers
How do you measure metal’s angles and lengths
What type of vice should you use when doing work on timber
Woodworking vice
How does a vacuum former work
- HIPS is heated
- Once hot, solid former pressed onto HIPS from a bed that can rise
- Vacuum, all air around former removed
- HIPS takes form of solid former
How do you cut polymers
Coping saw, Hacksaw
How do you cut metal
Hacksaw
Jack plane
Dressing timber down to size, rough
Smoothing plane
Removing very fine shavings
Reforming Processes
Injection moulding - thermoforming plastics, heated, injected into mould
Extrusion - thermoforming plastics and metals, heated then pushed through a die
Sand casting - metals, melted and poured into mould of special sand
Die casting - metal melted and forced into hardened tool steel mould
What are the different wood joints
- Mortise and tenon (slip into hole)
- Dovetail joint (satisfying)
- Comb joint (less satisfying)
- Butt joint (blocked ends)
- Mitre joint (photo frame corner)
- Lap joint (clasp two pieces 🤝)
- Dowel joint (small circular rod)
- Biscuit joint (like dowel but a leaf)
What is a composite
A term to describe material made by combining two or more materials together
What is a ferrous metal
Metals and alloys containing iron
What is a non-ferrous metal
Metals and alloys that do not contain iron
What is work hardening
Non-ferrous metal continuously bent, hit or shaped over period of time
What is annealing
Heat and then let the metal cool. It’s molecular structure changes and can be cut and shaped more equally.
What is a thermoforming plastic
Soften and become malleable when heated.
Thermoforming plastics:
Nylon - low friction characteristics, good chemical resistance
LDPE and HDPE (polyethylene) - resistant to chemicals and some float
Polyvinyl chloride - resistant to chemicals and solvents, good tensile strength and impact resistant
Acrylic (PMMA) - hard, good resistance to UV light and weather, tensile strength
Polystyrene - poor resistance to UV light
Polypropylene - high resistance to chemicals and stress, flexible
ABS - durable, resistant to chemicals and weather, rubber like properties
What’s are thermosetting plastics
Plastics that harden when heat is applied
Thermosetting plastics:
Polyester resin - stable, low-cost, easy to use, good mechanical, chemical resistance and electrical properties
Epoxy resin - high adhesive strength, electrical insulation and food chemical resistance
Melamine formaldehyde - hard an chemical resistant, resistant
Urea formaldehyde - high tensile strength, surface hardness, low water absorption
Phenol formaldehyde - high hardness, good thermal stability and chemical resistance
How is steam bending completed
Thin layers of timber into a chamber
Steam introduced from one end
Timber absorbs water as steam cools
Malleable and flexible now
Positioned into former and clamped
Retain the shape of the former
How is laminating completed
Thin laminated of timber and bonding then over a former. Layers need to be held in place while adhesives cure and set
Temporary joining
Using components with a screw thread
What is permanent joining
A process that cannot be easily reversed
What type of drill is used for cutting holes at 1-13mm
The twist drill
What type of drill is used for cutting holes at 13-40mm
Spade drill/ Forstner bit
What type of drill is used for cutting holes at >40mm
Hole saw
How does CAD relate to CNC machines
CAD creates the design geometry; CAM designs the tool path while CNC uses the output from the CAM to actually make the part
Metal finishes:
Galvanising - chemical process coats the base material in zinc
Anodising - electrolysis, acid + electrical current for protective layers on base material
Electroplating - chemically using electricity to add layers of other metals
Paint - spray or brush
Oil/grease - sprayed, rubbed or smeared onto exposed surface areas
Polish - machine buffing or by hand using a cloth
Plastic coat dipping - metal dipped into tank of thermoplastic coating removed, and left to cool
Powder coating - powder is a applied via an electrostatic spray gun. Product heated, powder melts
How do jigs and formers work
Holds pieces of material together so they can be joined
How does brazing work
Two pieces of metal heated, a third metal introduced to the joint being heated. Once molten heat removed and brass cools and solidifies
How does soldering work
Where solder “flows” along the cleaned components bonding then together once it solidifies
How does welding work
Heated together and join after it cools and solidifies
How does riveting work
Small piece of metal inserted into a hole. Deformed to the extent it cannot be removed
