Casting
Casting forms a jewellery piece by pouring molten gold or another metal into a mould made from a master model.
Casting is the moment a design becomes solid metal. A mould is made from a master model, the metal is melted, and it fills the cavity to take the shape of the piece. Almost every ring, pendant and setting begins life this way before it reaches the bench for setting and finishing.
From master to metal
The master, carved by hand or produced from CAM, is used to create a mould. Molten gold, platinum or silver is then introduced, often with the help of vacuum or centrifugal force so the metal fills every fine detail before it cools.
Once the metal solidifies the mould is broken or opened, and the rough piece, called a casting, comes out ready to be cleaned, sized and finished.
What good casting depends on
Temperature and timing decide quality. Metal that is too cool will not fill thin sections, while overheating causes porosity, tiny gas holes that weaken the piece and show up during polishing.
For fine jewellery the lost wax method is the standard route, because it captures detail cleanly and produces consistent results batch after batch.
- Casting pours molten metal into a mould made from a master model
- Vacuum or centrifugal casting helps metal fill fine detail
- Temperature control prevents incomplete fills and porosity
- Lost wax casting is the standard method for fine jewellery
Casting, in short.
What metals can be cast?
Gold in its various karats, platinum and silver are all routinely cast for jewellery. Each has its own melting point and casting behaviour, which the caster accounts for when setting temperatures.
What is porosity in a casting?
Porosity is tiny gas holes trapped in the metal, usually caused by overheating or poor casting conditions. It weakens the piece and can appear as pits during polishing, so casters work to avoid it.
Is casting done by hand or machine?
Both. The metal is melted and poured using casting equipment, but the mould making, cleaning and finishing around it involve skilled hand work at the bench.
Related terms
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