Think for a moment about the jewelry that you wear. Do you wonder how it might have been made?
I have written before about how I create some of my pieces using traditional fabrication techniques (see my post “Staring Into Space”). I start with sheets of precious metal and wire in various thicknesses. I cut, form, and solder. Then I file, sand, and polish. Then I set stones. Each piece crafted this way is a mini construction project.
But I have designs in my head which are not suited to this style of making jewelry. So I’ve entered the world of wax carving. I recently returned from a workshop at the studio of Kate Wolf in Portland, Maine. Kate is an “educator, jeweler, and tool maven.” I first met her in 2008 at the Tucson Gem Show, where she gave a brief demonstration and lecture at the Rio Grande “Catalog in Motion” event. Ever since then, I had wanted to take one of her workshops, and this year the stars aligned so that I could do so.
I am just beginning to learn about wax and experiment with new designs. As you read this, remember that I am in a galaxy far, far away from experts in this field, but I want to share some of what I’ve learned.
Why Utilize Wax Carving Instead of Fabrication?
Some new designs that I want to make involve curves and shapes that would be difficult to form in metal, designs which I think of as miniature sculptures. Wax carving will allow me to play around with such designs. The wax itself is a relatively inexpensive material, so unlike working directly with precious metals, the cost of the material is no barrier to experimentation. And unlike stone or metal, it is a forgiving material to work with. If you accidentally cut a deep gouge or remove too much, you can melt on more wax, let it harden, then resume carving.
Here is one of my class projects as it came together:
The second reason I’m interested in wax carving is that I can create jewelry in the more expensive precious metals, such as 14kt or 18 kt gold, with minimal metal waste. When I fabricate using a sheet of metal, there is a certain amount of scrap material left over after I’ve cut the desired shapes. I save my scrap, and eventually I recycle it by casting ingots, or send it to a refiner. With the cost of silver, this is an overhead I can carry. But not with the cost of gold (which is currently around $1,200 per ounce).
Types of Wax
Jewelry wax comes in a variety of formulas and forms, each suitable for a different process. And within each major category of wax there are variations. Here are just a few examples that I’ve worked with.
Modeler’s Wax is a soft wax that can be purchased as sheets of varying thickness as well as in shapes that mimic wire: round, half round, square, etc. As the name implies, it is soft and pliable and has a very low melting point. I have used them to very quickly mock up a design or shape.
As when working with sheet metal and wire, you create a piece in an additive fashion: cut a shape, form it, and connect elements by melting additional wax into joints. Connections must be done very, very carefully because of the low melting point of the wax.
Soft wax cannot be carved or filed or sanded, so in my (limited) experience the end result is rather rough. The refinements have to happen after the piece is cast.
Carving waxes are hard with a melting point around 240°F and are, as the name implies, suitable for carving. As with a sculpture that starts as a block of stone, a wax carving starts with a block of wax and the design emerges by removing wax. Saws and burrs are used to quickly remove the bulk of material, and then hand tools are used to carve and refine and the design.
A skilled wax carver can achieve precise and intricate detail, and the wax can be finished to a highly refined point, so that minimal polishing and finishing work is necessary once the wax is cast.
Other Types of Wax
Yet other types of wax are used for injecting into molds or 3-D printing. Or other purposes I don’t yet know about!
Needless to say, I returned from my class with my suitcase half-full of carving waxes and NEW TOOLS. Here’s just a few of them, a wax pen and a set of carving tools.
The wax pen is used to melt tiny amounts of wax to be used in joining two pieces of wax, or building up wax to repair an error. It can be set to a limited range of temperatures, because different waxes have different melting points.
From Wax Model to Finished Jewelry
So what happens after I’ve finished carving a design in wax? The wax will be cast using metal — in my work this will usually be either sterling silver or 14kt or 18kt gold. But it could also be platinum or copper or pewter or brass, to name a few examples.
Casting refers to the process by which molten metal is poured into a mold and allowed to harden. The mold is created by positioning the wax model inside a metal flask and pouring a plaster of paris-like substance called investment around it. The investment hardens very, very quickly, encasing the wax. Prior to this step, a rod of wax will be attached to the wax to create a pathway from the wax model to the surface of the investment — this is called a sprue.
The flask is then placed in a kiln and the wax melts out via the sprue channel, leaving an empty mold of the design. Then the molten metal is poured in. Usually a centrifugal or vacuum system is used in order to ensure that the metal flows into all parts of the mold. To get the cast metal out of the mold, the flask is submerged in water and the investment surrounding it dissolves. This whole process is known as lost wax casting, because your wax model, and the casting mold, are destroyed during the process.
Multiple copies of the same design can be produced by making a re-usable mold. Wax can be injected into the mold and removed without damaging the wax or the mold, thus many wax copies of the same design can be easily created, and they can then be set up in a way that they are all cast at the same time.
You can see examples of my custom fabrication work — and coming soon, wax work — at studio44jewelry.com.