A Detailed Guide to Lost-Wax Casting

Lost-wax casting dates back 6,000 years and is one of the oldest metal-forming methods. While its popularity has diminished over the years, it is still used, although very rarely, in various industries, including jewelry, dentistry, art, engineering and product manufacturing. The process is ideal for creating simple or complex objects. While the process may be labor-intensive, we love it for creating stunning custom pieces with intricate detail in the jewelry industry. 

You can find more information on our web, so please take a look.

What Is Lost-Wax Casting Jewelry?

Also known as investment casting and cire perdue, lost-wax casting is the process of making a metal object from a wax model. A mold is set using wax, which is then melted away, resulting in a cavity. Jewelers can then add the metal to the cavity and create a custom piece. This method is ideal for jewelers as it allows them to capture fine detail in the metal. Lost wax casting is also a highly versatile technique as jewelers can use various metals, including gold, silver, bronze, brass, copper and aluminum, to cast their designs.

Several types of specialty wax may be used for this casting method; however, Microcrystalline wax is often the most suitable option. It is pliable, slightly sticky and easy to work with due to its medium to soft consistency. While paraffin wax may be used to cast molds, it is better suited as an additive to harden existing wax models. Jewelers still need to have some knowledge about other specialty wax, including their melting points, as they can use them for specific purposes such as carving, modeling or patching.

The Lost-Wax Casting Process

The lost-wax process can vary slightly between industries; however, they generally follow the same steps and create a mold from a wax model. When making a custom ring, experienced jewelers create a wax model and use it to form a mold. Our skilled artisans hand-carve our wax models as it allows us to provide more detail. We can also inspect the wax model for flaws, and clients can adjust their custom design before we make the metal product.

The wax model is attached to a sprue which also serves as the channel for molten metal to enter the mold. The ring model is then surrounded by investment, or high-grade plaster, to create the casting. A vacuum will remove any air bubbles from the plaster to ensure the quality of the cast and produce a perfect mold.

Jewelers then dry the cast before hardening the investment in a kiln and melting the wax. The cast has a ring-shaped cavity ready to hold the molten metal with the wax removed. The metal is poured and set before removing the cast, leaving a perfectly shaped ring attached to the sprue. The sprue is removed, gemstones are set in the ring and then it is finished and polished, making it ready for the client. 

History of Lost-Wax Jewelry Casting

Lost-wax casting is used worldwide with the oldest known object, an amulet, created in the Indus Valley over 6,000 years ago. Historians have found discoveries of scepters, furniture and sculptures in many other places, including Nicaragua, Vietnam, Israel and Nigeria, showing how far this casting process spread over the years. By the 18th century, the process of using lost-wax casting to create sculptures and other ornaments was supplemented with piece molding to keep up with the demands of growing industries. While it was never completely forgotten, lost-wax casting went through a decreased popularity cycle and was &#;rediscovered&#; again. 

Even to this day with the introduction of modern technology, lost wax casting is one of the most accurate methods of reproducing intricate detail and design in metal jewelry. 

Applications of Lost-Wax Casting With Digital Technologies

Lost-wax casting was first used to produce fine jewelry and, although it is not very common, is still an application used today to create a wide variety of pieces. While technology and 3D printers allow for a smoother workflow, our talented artisans combine this with hand carving to create more intricate and delicate details on custom jewelry designs.

At JPratt Designs, we use state-of-the-art CAD software to develop a concept and then create a lost wax cast model that clients can view and try on before confirming their custom design. We set gemstones in this model to give you an accurate impression of the finished product. This process allows you to express your concerns and for us to make any adjustments to your custom design before setting diamonds and stones in your chosen metal.  

Create Custom Jewelry at JPratt Designs Using the Lost-Wax Casting Process

With competitive price and timely delivery, Yitai sincerely hope to be your supplier and partner.

With extensive industry experience and providing our customers with fine jewelry for more than 30 years, you can trust our artisans to create a custom design that you&#;ll love for years to come. Contact us today and schedule your appointment with our team of experts.

Investment casting, also known as lost wax casting, is a metal casting method for shaping metal parts that often have more intricate cavities or geometries. The process begins with shaping the final part out of wax, adding a ceramic shell over the wax, and then melting the wax out of the shell. Molten metal is then poured into the ceramic shell, hardened, and then removed for the final metal part.

One of the keys to the process is the type of wax used. The wax arrives in pucks, billets, or pastilles (mini beads). This guide covers the common types of investment casting waxes. The most common waxes include filled pattern wax, non-filled pattern wax, runner wax, sticky wax, and water-soluble wax.

Filled Pattern Wax

Filled pattern waxes contain additives such as ceramic or metal powders to enhance mechanical properties and dimensional control. One common additive is bisphenol-A (BPA). Filled pattern waxes are commonly used for large or complex patterns where strength and rigidity are crucial. The additives can also help by minimizing shrinkage during the cooling period. When pouring metals at various temperatures, a filled pattern wax is a great option for creating the mold as it allows greater dimensional tolerances.

However, with additives, filled pattern waxes are often costly compared to non-filled pattern waxes. They can be trickier to process and work with than non-filled waxes and availability of the material can be a concern. With additives, recycling the wax can be difficult and sometimes not possible. Density issues arise with the fillers, and filled pattern waxes sometimes must be burnt out of the ceramic shell.

Non-Filled Pattern Wax

Non-filled pattern wax, also known as unfilled wax, is a simple wax formulation without additives. These waxes are widely used for run-of-the-mill investment casting applications where cost and ease of use are priorities. Non-filled pattern waxes are easier to work with, without having additives. They have good flow properties and dewaxes from the shell entirely &#; meaning easy to recycle and reuse. Overall, non-filled pattern waxes are highly versatile, offer exceptional surface quality, and are available in various formulations and grades.

On the flip side, non-filled pattern waxes tend to offer lower strength and dimensional stability compared to filled pattern waxes. They are susceptible to shrinkage and distortion during cooling, which may then require wax chills. When it comes to project scale, large or complex patterns requiring added strength are not great fits. Non-filled pattern waxes are suitable for small and medium projects or complex patterns and cavities.

Runner Wax

Runner wax, also known as gating wax, has excellent flow properties. This type of wax is critical in ensuring the proper filling of molds. This helps with precise gating system formation. It has good adhesion to mold surfaces, ensuring leak-free gating channels. The use of runner wax helps optimize the flow of molten metal and minimize the formation of defects in the final parts. Runner wax has a lower melting point compared to other waxes, which aids in the wax completely melting out and not requiring higher temperatures, potentially hurting the shell.

Sticky Wax

Sticky wax, as the name suggests, is a tacky wax used for assembling various wax patterns. The adhesive properties make it crucial for intricate parts or repairs. Sticky wax is easy to manipulate and shape, allowing for wide versatility in its application. It works well with numerous wax pattern types.

Sticky wax can only be used for pattern assembly or repair tasks, it is not a substitute for a pattern wax. Excess sticky wax residue can be tricky to remove, so extra cleaning can be required. Low temperatures can cause sticky wax to become brittle and increase the risk of breakage.

Water-Soluble Wax

Water-soluble wax offers a sustainable alternative to traditional pattern wax materials. Parts with intricate geometries and cavities are aided by using water-soluble waxes. The cores created from water-soluble wax can be placed within a pattern wax mold and then easily dissolved while leaving the rest of the mold intact. By dissolving in water, this soluble wax leaves behind clean and residue-free molds. As environmental concerns continue to arise, water-soluble waxes are a great solution.

Investment casting waxes come in a diverse array of options, each catering to specific casting requirements. Begin your next metal casting project at MetalTek today.

Are you interested in learning more about lost wax investment casting? Contact us today to secure an expert consultation!