How to Sand Cast Fire in Place Cultured Opals

Sand Casting Healing Phoenix Lapidary Fire in Place Cultured Opals transforms an ancient jewelry-making technique into modern, mesmerizing art. This timeless method utilizes jeweler’s sand to craft molds, with materials like Delft clay and even beach sand contributing to the unique textures. Each casting is a custom-made creation, allowing artisans to produce one-off pieces without resorting to outsourcing to casting houses.

When it comes to sand casting stones, it’s a tricky business. Stones can crack or shift, and there are no guarantees. I went to Nadine Citerne of Nadine Suzanne Jewellery, a generous and trusted educator specializing in sand casting. Drawing inspiration from the ocean, Nadine’s sand cast jewelry often incorporates beach sand, resulting in remarkable textures and organic details that stand apart. Nadine was thrilled with the challenge of trying and proof-testing the Cultured Fire in Place Opals. She put the Cultured Opals through the paces with meticulous testing, and the successful pieces she created are beautiful.

Let’s take a deep dive into the
Sand Casting Process.

Different Models Can Be Used for Casting

Nadine often employs wax models fashioned to allow 0.5mm of space for the metal to flow behind and secure the stone. A master, usually made of a durable substance such as wood, plastic, or metal, is created. Another possibility is found objects such as beach shells and metal or plastic buttons.

A flask, packed tightly with the jeweler’s sand, is used to capture all the details of the master when pressed into it. Common designs used in Sand Casting include cast rings, pendants, and bezel rings.

Sand Utilized in Testing the Cultured Opals

Nadine used:

• Red Clay from DIY Castings and

• Delft Clay from most jewelry supply stores.
   

Sand Casting Flask

This specially open-ended container comprises two parts; a male and female part holds the sand and supports the mold. The male side has a protruding lip and vent holes.

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Filling the Flask with Sand

The male side of the flask is filled and leveled off with sand from behind, using a hammer.

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Inserting the Wax Model 

Pressed halfway into the sand, the wax model is brushed with baby powder to prevent sticking.

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Filling the Female Side of the Flask with Sand

The female side of the flask is placed on the male side, and the sand is packed tightly from behind to capture all the mold detail and level off.

Removing the Wax Mold 

The flask is carefully separated so as not to disturb the impression created in the sand by the model. Then, the wax model is carefully removed, leaving a cavity for the metal.

Creating Sprue and Vents

A Sprue and funnel are created to transport metal poured into the mold. The sprue and funnel join to the recess created by the wax mold, and the funnel is designed to pool any excess metal.

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Vent holes are added to assist in allowing the gas to escape. The vent holes also serve as a vacuum, drawing the metal down.

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Pouring the Molten Metal

Using a Smith Little Torch, metal is heated until molten and poured into the opening you made above, filling the negative space created by the mold. It is then allowed to cool into the desired shape.

It is noteworthy to mention that the most common type of torches used are MAPP gas bottles—these are handheld torches, but they don’t melt the silver as quickly as the Smith torch.
 

There are two types of Flasks: Top Pour and Side Pour

• Top Pouring metal into the flask is commonly used for pendants and flat objects, and

• Side Pouring metal into the flask is typically used for rings.
   

Extracting the Casting

Once the metal has solidified, the mold is immediately opened, and the raw cast is extracted and set aside to cool. Due to the risk of thermal shock to the Cultured Opals, it is allowed to cool naturally.

If there are no stones set in the piece, it can be quickly cooled in water.

Now for the Fun Part Sand Casting Fire in Place Cultured Opals 

Cultured Opal Preparation
Once the mold is created, the Healing Phoenix Lapidary Cultured Opals are meticulously cleaned and placed within the cavity. Each Cultured Opal is coated with a thin layer of pawpaw ointment (petroleum jelly) on the table to prevent movement during the process. However, keep in mind that when sand casting with stones in place, there’s no guarantee that the stone will stay perfectly positioned or even survive the process. The ‘cast in place’ technique gives each piece a unique, rough, and organic feel.

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Casting Cultured Opal Placement

All Cultured Opals have pawpaw ointment applied to their tables to prevent them from shifting in the mold. After the casting, the rings were not quenched in water, but left to cool naturally, avoiding the risk of thermal shock.

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Cultured Opals Used in Casting

Both faceted and cabochon Cultured Opals were put to the test. Faceted Opals ranging from 3 to 6 mm in size were successful. However, some cabochons did not withstand the process. Interestingly, the shallow 4 x 6 mm ‘Cool Mint’ Cultured Opal Cabochon did survive, likely due to its shallow depth. Cabochons are generally less favored in sand casting or lost wax methods because they are poor conductors of heat and prone to thermal shock during rapid heating or cooling.