How to Cast Rings From Wax

Jewelry casting can produce beautiful results.

Lost wax casting is a method of making jewelry that involves carving an item in jeweler's wax, placing the wax in a plaster mold and then filling, or casting, the mold with a molten metal. Since rings are circular objects, creating reusable molds that do not have seam lines is difficult; so many lost wax ring molds are destroyed in the ring casting process. Sterling silver is a good metal to use for beginning ring casters because of its low melting temperature and cost.

Things You'll Need

• Jeweler's wax
• Rubber jeweler's base
• Wax pen
• Flask to fit rubber base
• Vestment
• Jeweler's kiln
• Crucible
• Sterling silver ingots
• Tongs
• Boric acid
• Bucket of water

Instructions

1. Carve the desired ring design from the block of jeweler's wax. Start off simple to get a better understanding of the lost wax casting process and carve a simple, unadorned ring. Ensure that the ring is sized correctly for the wearer. Lost wax casting creates items exactly the size and proportion of the wax model.

2. Attach the ring to the rubber base. Take a wax pen, similar to a soldering iron for wax, and connect the carved wax ring to feed lines of wax, called sprue, to the center hole on the rubber base. Later this hole will be used to inject the molten silver into the mold.

3. Place the flask on top of the rubber base around the wax ring. The flask is a thin-gauged metal pipe that holds the plaster around the wax ring while it dries to form the mold.

4. Fill the flask with vestment, a type of plaster designed to be used in lost wax casting. Vestment is water soluble and is made from a very fine powder, enabling it to capture more detail than plaster made from lager grain powder. Leave the vestment drying in the flask overnight. Remove the rubber base from the bottom of the dried vestment mold. Removing the base will leave a cavity-like funnel into the mold.

5. Place the flask and mold into a kiln funnel-side up. Heat in steps of 100 degrees up to 1200 degrees Fahrenheit. The heat from the kiln will burn the wax ring and sprue lines out of the mold, leaving the mold empty. Do not use a standard oven, as fumes from the hardening vestment may be toxic.

6. Coat the inside of the crucible with boric acid. This keeps the silver from becoming contaminated with other metals leftover in the crucible. Heat the silver in the crucible until it is molten. The silver should be completely molten; if it's too cool, it won't completely fill the mold, but if it's boiling, air bubbles will be visible in the final ring. Slowly pour the silver into the funnel hole. Special equipment, such as centrifugal casting and vacuum casting machines, can be used in place of this step if they're available.

7. Let the mold sit for an hour. Sterling silver cools very quickly, but the mold should not be picked up by hand. Pick up the mold using the tongs and squelch it in a bucket of water. The water-soluble vestment will dissipate in the bucket, leaving the silver ring. The ring will need to be polished and possibly sanded to remove any extra silver from the rubber base funnel and sprue lines.

Tips & Warnings

• Lost wax ring casting should only be attempted after proper safety training and with the correct equipment.

References

• Professional Jeweler: Cast Jewelry: A Primer
• Ganoksin: Casting Notes for Silver Lost Wax Casting
• Jeweler Cam: Lost Wax Casting
• CaneQuest.com: Lost Wax Method