How Does the Jewelry Casting Process Work–and Why Is It Essential in Custom Jewelry?

Most jewelry shoppers don’t often think about the specifics of how their jewelry is made. In most cases, jewelry is purchased online or chosen from a display case at a local store. In such cases, your only worry might be to get it sized properly.

However, if you're shopping for a piece of custom-designed jewelry, that changes everything. It becomes more likely you'll want to understand the production process–which isn’t well known.

How the custom-designed jewelry process works

Everything begins with the design phase. That's when you’ll meet with the jeweler to discuss your preferences, including style, stones, metal, and setting. You’ll likely receive a sketch for approval before moving forward.

Next comes the casting. After casting, the piece is set with any stones, polished to a bright finish (unless you’ve chosen an alternative like satin), sandblasted, or hammered. Finally, during quality control, the ring is carefully examined under a microscope for loose stones, scratches, or imperfections, ensuring that everything is flawless and ready for you to wear.

Now that you have a basic understanding of the overall process, let's dive deeper into the casting process–which is the focus of this article.

How does jewelry casting work?

Casting is the most complicated part of the jewelry-making process. It's how your jewelry becomes metal.

There are several different ways that jewelry can be cast and each one has its pros and cons. Understanding jewelry casting styles can add a new layer of appreciation to the jewelry you’re purchasing. It’s a fairly sensitive process that is part art and part science.

There are different casting styles (which we'll get into). We highly recommend you ask your jeweler which one they use and why.

What is jewelry casting?

Jewelry casting is the stage in the production process where molten metal is poured into a mold to form the desired shape. The metal fills the hollow space left by the casting material and then cools into what’s known as the raw casting—an unfinished piece that will later be cleaned, polished, and completed. Once the jeweler has this rough metal, it can be customized by setting stones, polishing, etc. to finalize the design.

Lost wax casting

Lost wax casting is the most commonly used casting method today—and likely the oldest, with a history that dates back thousands of years.

In lost wax casting, once you approve the sketch of your design, a 3D model is carved in wax so you can view it from all angles. If you're satisfied with the wax model, it’s attached to a wax sprue—a piece that connects the model to the casting crucible, which holds the investment material. The model can then be cast on its own or joined to a larger wax tree to be cast alongside other pieces made from the same type of metal.

The wax tree is then encased in investment, which is like plaster, and allowed to dry. Once the investment hardens, it’s placed in a kiln where the heat melts and burns away the wax. This leaves behind a hollow mold in the exact shape of the jewelry design.

The metal is then heated through various methods and poured into the investment to fill the empty spaces. Once the metal cools, the investment is broken apart and you are left with the raw metal form of your jewelry.

Centrifugal Casting

Centrifugal casting is a type of lost wax casting where the investment is placed into a machine that spins at a fast pace after the metal is poured in–which forces the metal into all of the small empty spaces. This step is especially important for intricate designs with fine details, as it ensures the molten metal can flow into even the smallest spaces within the mold. The centrifugal force reduces the prevalence of air bubbles, making a more solid piece of jewelry.

 
Vacuum Casting

Vacuum casting is another iteration of lost wax casting where suction is used to assist the metal into the empty space in the investment. The investment mold is placed inside a vacuum chamber and once the liquid metal is poured in, the vacuum starts and helps it flow, again reducing the likelihood of air bubbles or empty space in the final design. Vacuum casting is often used for larger pieces of jewelry or items that have intricate details. It allows for less work during the final stages for the jeweler to do by hand.

Sand casting

One of the oldest casting techniques, sand casting is surprisingly simple. A model of the design is pressed into sand, leaving an empty space in the shape of the design. Liquid metal is then poured into the empty space and once it cools, the sand is removed and you’re left with a raw casting of your jewelry design. Sand casting is not as precise as lost wax casting, so it is not often used for designs that have a lot of small details.

Die casting

Die casting is commonly used in industrial settings to produce large quantities of mass-manufactured items using non-precious metals. In this process, molten metal is injected into a reusable steel mold. Once the metal cools and solidifies, it’s removed from the mold, resulting in a raw casting ready for further finishing. While it’s not feasible for custom gold and platinum designs, it can be used for costume jewelry.

3D printing

3D printing is used along with CAD (computer aided design) to make wax or resin models of the jewelry design. Once the 3D print is completed, the design can be cast using a lost wax casting technique. Designs that are very detailed can really benefit from 3D printing because these small designs can be calibrated precisely using CAD and easily printed.

Which casting style is best?

This question really depends upon the type of jewelry you’re looking for. If you are searching for inexpensive costume jewelry, then die casting is your best bet. If you want something with a fair amount of detail, then one of the variations of lost wax casting would be a nice option. Each jeweler may have a method they prefer, so feel free to ask your jeweler which one they use.

Although it may not cross your mind while shopping, every piece of jewelry in the display case has gone through a meticulous, multi-step process to become the beautiful item you or your loved one eventually wears. The casting method your jeweler uses is likely chosen based on the specific type of jewelry being crafted. By selecting an experienced jeweler, you can trust that they have the skill and knowledge to ensure your design is cast successfully—resulting in a lasting piece you’ll treasure for a lifetime.