How It's Made: Lost Wax Casting Process

What Is Lost Wax Casting?

Lost wax casting is a metalworking technique in which a model carved from wax is used to create a mold. The wax is then melted away, or "lost," and molten metal is poured into the cavity left behind. The result is a metal reproduction of the original wax carving, capturing every detail the craftsman put into the model.

The technique is one of the oldest known methods of metal forming. Archaeological evidence places its use as far back as 4000 B.C. in the ancient Near East. It was practiced across cultures for millennia: Egyptian goldsmiths, Greek bronze casters, and the Celtic metalworkers of early medieval Ireland and Britain all relied on variations of the same fundamental process. The great masterpieces of Celtic metalwork that inspire our designs today, pieces like the Tara Brooch (circa 750 A.D.), were created using charcoal-fired foundries and hand-fashioned molds, without the benefit of commercially engineered materials.

The Steps of Lost Wax Casting

While modern tools have refined the process, the core steps remain essentially the same as they were thousands of years ago. In the video below, Stephen Walker walks through the complete process as he makes a pair of Celtic wedding rings from family gold.

1. Carving the Original Wax Model

Every design begins as a hand-carved wax original. The craftsman shapes a block of jeweler's wax using fine carving tools, files, and heated instruments, building up the interlacing lines and three-dimensional relief that define the piece. This is the most time-intensive step: the interlacing lines of a Celtic ring, the raised relief of a Celtic cross pendant, or the flowing curves of a zoomorphic animal are all carved into the wax with precision. Every detail, every texture, every line in the finished piece traces back to the craftsman's work at this stage.

2. Making the Rubber Mold

Once the original wax carving is perfected, a rubber mold is made from it. This mold captures every surface detail and allows the design to be reproduced. Hot wax is injected into the rubber mold using a wax injection pot; after a moment to cool and harden, the wax copy is removed. The result is a faithful wax replica of the original carving, ready to be cast in metal. This step is what allows a single hand-carved design to become a piece that can be made again for different customers, each time cast and finished individually.

3. Investing the Wax

The wax tree is placed inside a cylindrical container called a flask. The flask is then filled with investment, a heat-resistant plaster material that hardens around the wax and captures every surface detail. The investment must cure thoroughly before the next step.

4. Burning Out the Wax

The flask is placed in a kiln and heated gradually to temperatures that melt and vaporize the wax, leaving behind a hollow cavity in the exact shape of the original carving. This is the step that gives the process its name: the wax is "lost," sacrificed so that metal can take its place. The sprue channel becomes the gate through which molten metal will enter the mold.

5. Casting the Metal

With the mold still hot, the flask is loaded onto a centrifugal casting machine and precious metal is heated to its melting point with a torch. Sterling silver reaches a liquid state at approximately 1640°F (893°C); gold alloys melt at similar temperatures depending on karat and composition. Once the metal is molten, the caster is released and centrifugal force drives the liquid metal into the mold cavity, filling every detail of the space left by the wax.

For pieces made from a customer's family gold, this is where heirloom metal finds new life. The gold from a great-grandfather's wedding ring, a family cross, or other cherished pieces is weighed, supplemented if needed to reach the required weight, and melted down to become the raw material for the casting. As Stephen puts it, it weaves things together even a little more symbolically.

6. Finishing the Piece

Once the metal has cooled, the investment mold is broken away to reveal the raw casting. From here, the piece requires careful hand-finishing: the sprue is cut away, surfaces are filed and sanded, and the piece is sized and polished. For Celtic knotwork in sterling silver, the recessed channels are given an antiqued finish to create contrast with the raised surfaces. If gemstones are part of the design, they are set at this stage. The finished piece is a faithful reproduction of the original wax carving, rendered in precious metal.

Design and Meaning

A wedding ring is a symbol of eternity; there's no beginning and no end. The Celtic knotwork on a Celtic wedding ring reinforces that idea, because there's no beginning or end in the knot. The overs and unders of the Celtic weaving are also symbolic of how two lives are joined and intertwined. When those rings are cast from family gold, the symbolism deepens further: generations of meaning carried forward into something new.

Why Lost Wax Casting Matters for Celtic Jewelry

Celtic knotwork, with its continuous interlacing lines and intricate geometry, demands a process that can capture fine detail and complex three-dimensional forms. Lost wax casting is ideally suited to this work because the craftsman carves directly into the wax, maintaining full control over depth, texture, and the interplay of raised and recessed surfaces. The kerbschnitt, or chip-carved, style found in early medieval metalwork relies on exactly this kind of precision, and the lost wax method allows modern craftsmen to work in that same tradition.

Each wax carving is an original. Even when a design is reproduced through a rubber mold, every casting is individually finished by hand: sized, polished, and inspected. This is what distinguishes handcrafted Celtic jewelry from mass-produced stamped or machine-made pieces. The human hand is present at every stage, from the first cut into the wax to the final polish.

Watch the Process

In this video, Stephen Walker walks through the complete lost wax casting process as he makes a pair of Celtic wedding rings from family gold. You can follow the journey from wax injection through casting, finishing, and sizing.

You can also check out the history behind some of our pieces like the Spiral St. Brigid Cross along with progress shots along the way in many of our blog posts. Our Facebook and Instagram pages also feature works in progress as pieces move from concept to finished jewelry.

About the Author

Stephen Walker has been handcrafting Celtic jewelry in Andover, NY since 1984. A silversmith since the early 1970s, he has spent decades refining lost wax casting techniques and researching the ancient mold-making methods behind early medieval Celtic masterpieces.

Learn more about Stephen & Susan Walker →