A process unchanged for three thousand years. We explain how your photograph becomes a piece of metal that will outlast us all.
The oldest known lost-wax cast object is a small copper amulet, found in present-day Pakistan, made approximately six thousand years ago. The technique used to make it — shape wax, encase in clay, burn out the wax, pour in metal — is identical in principle to the technique we use on our bench in Melbourne today. Some processes survive because nothing better has been invented to replace them.
Stage One: The Wax
Everything begins in jeweller\'s wax. It is a material of precise engineering: calibrated to carve cleanly, to hold fine detail without crumbling, and to melt at a low enough temperature to burn away cleanly inside the investment mould. Our sculptors work with tools made from dental instruments — small, precise, built for working at close range.
A portrait medallion at the wax stage is a delicate object. It cannot be dropped. It must be handled with nitrile gloves to prevent the oils in skin from affecting the surface. It is, at this point, the only existing form of the portrait — and it is about to be destroyed.
Stage Two: Investment
The wax is mounted on a sprue — a small wax rod that will form the channel through which metal flows — and the assembly is placed inside a metal flask. Investment plaster, mixed to a precise ratio, is poured in under vacuum to remove air bubbles. A single bubble trapped against the surface of the wax will produce a void in the final casting — a pit, a missing detail, a ruined piece.
Stage Three: Burnout
The invested flask goes into a kiln. The temperature is raised slowly — too fast and the investment will crack — until the wax melts and flows out through the sprue hole. The temperature is then increased further, to around 700°C, to burn away any remaining wax residue. What remains is a cavity in the investment plaster, shaped precisely to the wax model. It is an absence waiting to be filled.
“The wax, at this point, is the only existing form of the portrait — and it is about to be destroyed.”
Stage Four: Casting
The metal — alloyed, melted in a graphite crucible — is injected into the hot flask under centrifugal or vacuum pressure. The metal must fill every part of the cavity, including the finest surface details. If the flask is too cold, the metal freezes before it reaches the extremities. If it is too hot, the metal can penetrate the investment surface and produce a rough casting. The window of correct temperature is narrow.
After casting, the flask is quenched in cold water. The thermal shock disintegrates the investment plaster, releasing the raw casting. The sprue is cut away. The piece goes to the finishing bench.
Stage Five: Finishing
Raw cast metal has a granular surface that must be refined through progressive polishing — from coarse to medium to fine abrasive, finishing with a cloth wheel charged with polishing compound. On a portrait medallion, the raised areas are polished to a high reflective finish while the recessed areas are left deliberately matt, increasing the contrast that gives the portrait its three-dimensionality. This final stage takes several hours and is done entirely by hand.
When it is finished, the piece is washed in an ultrasonic bath to remove all polishing residue, dried, and inspected under a loupe. Then it is ready. Three thousand years of technique, in the service of one person\'s face.
