Casting: from wax model to finished jewellery
Cire perdue — the lost wax that gives form to metal
Not all jewellery is built piece by piece at the workbench. Many are instead shaped through casting, where liquid metal is poured into a mould and solidifies into the desired shape. The most widespread method in the goldsmith and silversmith trade is cire perdue — French for 'lost wax' — a technique dating back to ancient bronze age.
§How the freedom of self-employment feels
The process starts with a model in wax shaped exactly as the finished jewelry should look. The wax model is covered with a mold mass, typically a plaster mixture, that hardens around it. The mold is then heated so the wax melts — or is burned — out leaving a precise cavity in the mold with exactly the wax model's shape.
§From cavity to finished metal
When the wax is gone, molten metal is poured into the hollow cavity the mold has left—often using a centrifuge or vacuum system that forces the metal into the mold's finest details. When the metal has cooled, the mold material is gently broken away and the jewelry remains in solid metal, ready to be cleaned of sprues and finished with file and polishing.
§Digital wax — a modern shortcut
Today classical technique is often combined with digital design. A model is drawn in a CAD program and then printed in wax or wax-like resin on a 3D printer before being cast using the exact same cire perdue principle as a hand-modelled wax model. This makes it easier to repeat a design several times with identical results and to manufacture shapes that are difficult to model by hand — but many craftspeople still prefer to model wax by hand because it gives immediate creative control over the form.
| Step | What's happening |
|---|---|
| Wax model | The form is created in hand or digitally printed in wax/resin |
| Embedding | The wax model is covered by mold compound that hardens around it |
| Burn-out | The form is heated, the wax melts/burns out leaving a cavity |
| Metal casting | Melted metal is pressed into the cavity with centrifuge or vacuum |
| Post-processing | Form material is removed, sprues are cut off the jewellery is filed and polished |
§Quality control after casting
A cast item must always be inspected before work continues. Porosity — small cavities in the metal — can occur if the metal is not pressed completely into the mould's details and must be detected before the jewellery is polished and possibly sold. The sprues where the metal flowed into the mould must be cut and filed away so the transition becomes invisible in the finished surface.
- 01The wax model must be completely free of defects — every detail follows into the metal.
- 02The form material must have time to harden completely before the burnout can be carried out correctly.
- 03Metal type and temperature must match so the metal fills the mould without porosity.
- 04A cast piece is rarely finished from the mould — filing soldering and polishing complete the work.
Casting is therefore not a shortcut around craftsmanship, but yet another place where precision and an experienced eye determine whether the result is a flawless mould or a piece that must be scrapped.