Enhancements, processes and finishes Flashcards
What is work hardening?
A metal is cold worked, such as bending or hammering, the crystal within the metal become distorted, leading to improved tensile strength and hardness. When the crystals are distorted, they are prevented from moving freely, which results in less ductility.
What is annealing?
The meatal is heated and slowly cooled, so the metal crystals to grow and slowly move into place. It is used to make a work hardened metal less brittle and more ductile.
What is case hardening?
A process used to hardening the surface of steels, the steel produced has an outer casing of greater hardness and resistant to surface indentation, while the core keeps its soft properties.
It is carried out in two stages:
Carburizing- steel is heated in the presence of carbon.
Quenching- The hot metal quenched in water the seal the hard surface case while not affecting the inner core.
What is hardening?
The process of heating medium/high carbon steels and holding them at that temperature and then quenching it in a water bath. This increases the hardness but also brittleness.
What is tempering?
A process carried out after hardening to reduce the hardness and increase the toughness. The metal is heated below its critical point and then slowly air cooled.
What is an acrylic varnish?
Can come in three types either gloss, satin or matt. Provides a hard, tough, heatproof and waterproof finish.
What are water based paints?
Provides protection and colour. They make the surface aesthetically pleasing, tougher, harder and resistant to moisture.
What are stains?
Can add colour and help enhance the grain, but they have no protective properties.
What is a colour wash?
Adds colour to a wood whilst allowing the grain to show.
What is a wax?
It increases the surface hardness and toughness, whilst allowing the grain to show.
What is pressure treating?
Protects the wood for a long period of time from rot insect and fungal attack.
What is Danish oil?
Not very hardwearing finish, but maintains the natural look of the wood, whilst enhancing the grain.
What is thermoforming?
How does vacuum forming work?
A sheet of thermoplastic is heated until softened. A mould is then pushed up into the sheet and the vacuum is turned on, sucking the polymer over the mould. Once it cools the mould is lowered and any excess polymer is trimmed off.
