Jewelry by Marcy Kentz

How To Cast Jewelry

I was recently introduced a new medium: lost wax casting. I immediately became obsessed with carving wax. I trolled the internet for videos and how to articles on wax carving techniques. I was quite surprised with the small pool of content I found. So I have decided to put up some photos, tips and the general process of lost wax casting for anyone else who wishes to learn more.subject.

The ancient art of lost wax casting is a long processes with many steps.

The first step is hand carving the design out of wax which can take many hours, days or weeks to achieve the level of detail and intricacy of the design.

You start with a block or a tube of wax. Then you saw off a piece and carve it down to the general shape and size you want. Using good tools is a must. I recommend Wolf Wax Tool Set for carving wax. These carving tools are far more superior than all the others I have tried. The Wolf Tools are more expensive, but totally worth it. Extra coarse sand paper helps bring out the ring shape from the tube form. Also, a flex shaft makes the job go by a lot faster.

These are the very first pieces I made for casting. They were made with sheet wax and wire wax.

These two pieces are my first wax carvings, an eye and a skull as mourning jewelry. The pair represents the duality of life and death.

These rings are the wax models I carved for my Memento Mori and Visionary ring and pendant sets. (available at www.mkmk.bigcartel.com) There are 4 molds for these rings. The skull and eye are cast in bronze and the ring bases are cast in silver. The pieces are then soldered together in place after the spures are removed resulting in mixed metal rings.

Once you have the general shape of your design, its time for the details to come out. That's where the precision wax carving tools come in. Once you have the design close to what you want use this Matting/Polishing Paper to get the wax nice and smooth.

After the design is complete in wax form, the next step is to add "sprues" which are the channels that allow the wax to melt out and the metal to enter the mold.

These pieces have their sprues on them (the red wax) and are on the "button" of the casting canister. They are ready for investing. You want to have multiple sprues on your piece so the metal has more streams for entering the mold. This way you have a better chance that the casting will come out. On the flip side, hand sawing off the sprues and grinding them down is a lot of work. There is a fine balance between sufficient amount of sprues and too many sprues, it depends on each design.

This is what the pieces in the above photo look like right after casting. The sprues are still on and the metal is very dirty.

Now the piece is ready to "invest". Investment is the plaster used to make the mold. After the investment sets and dries it is ready to put in the kiln for about 8 hours to burn out the wax and get the casting canister up to the same temperature as the molten metal.

The piece is finally ready to cast. While the metal is heated up with a torch inside a crucible, the casting canister is taken out of the kiln and set next to the crucible in the centrifuge. The centrifuge is released and it rapidly spins to get the metal to fill all corners and details of the mold.

In this photo the metal is getting melted in the crucible inside the centrifuge

After it cools, the design is ready to be cleaned, saw and grind the sprues, file, polish, polish, and more polishing.

This was my very first casting. Only half of my wax tree came out. There are so many variables in casting that can effect the outcome. In this case, the hole of casting canister and the hole of the crucible didn't line up. When the centrifuge started to spin, not all of the metal made it into the casting canister and molten metal spewed all over the centrifuge.

These pieces are fresh out of the crucible. The bottom part is called "the button." When you see the button on the bottom of the casting canister, before you quench it, you know that the mold was filled with metal. Time to clean.

After all of the finishing work is complete, then the piece is ready as a "master mold". A rubber mold is made from the master. The rubber mold is used to make multiple wax copies. The whole casting processes starts over with a production run.

These mixed metal pendants get oxidized first, before many rounds of polishing. The oxidation gives them depth and bring out the texture in the metal. Personally, I like a more rustic look to my pieces so I always oxidize my silver.