The ancient art of lost wax casting is a long process with many steps by Marcy Kentz

From sketching my idea to finishing the pendants into a double strand necklace, the casting processes takes a lot of time, thought and design. These pieces are inspired by the passing of my father, the process of mourning his absents, honoring his life and making the most out of the rest of my life. On the back of the skull pendant it says dem bones. My dad reveled in cooking for our entire family and the tradition was to play that song while cooking the ribs. The back of the eye pendant says - keeping an eye out for the beauty in life. This is a reminder to not get too weighed down with sorrow from missing my dad. Life is full of beauty and the whole joy of living is finding beauty and appreciating it...all of it, including death.

 


Step 1 Carving the Wax

Hand carving wax 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.  A flex shaft makes the job go by a lot faster. Extra coarse sand paper and files help bring out the ring shape from the tube form.

Using a flex shaft is messy, but it gets the tube down to a ring shape quickly.

  These were the first pieces I made out of wax. I used sheet wax and wire wax and melted them together to make these rustic and tribal shapes.

 These are the first pieces I carved out of wax using crude dental tools. They are a pendant set, a skull and an eye representing the duality of life and death.

 I made these wax model rings after I finally invested in quality carving tools.  Using good tools make a world of difference. 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. I carved these pieces for my Memento Mori and Visionary ring and pendant sets.  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.

 

Step 2 Adding Sprues

After the design is a finished wax model, 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. With small wire wax you add vents to the top of the pieces. These little antennae give space for the gases during the casting process.

These pieces have their vents and 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.

 

Step 3 Investing

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.


Step 4 Casting

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.

The metal is getting melted in the crucible inside the centrifuge



Step 5 Cleaning, Filing and Polishing

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

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 (cool the metal and dissapate the investment in a bucket of water), you know that the mold was filled with metal. Time to clean.

 
This was my very first casting. Only half of my wax tree came out and there was no button on the bottom. 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.

 


Step 6 The Master Mold

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 with liver of sulfur, before many rounds of polishing. The oxidation gives them depth and bring out the texture in the metal. I like a more rustic look to my pieces so I always oxidize my silver.

 
These rings  just went for their 3rd round of polishing.

 
Wax carving before casting

 
Silver ring  after casting, oxidizing and polishing.