Making a Sterling Pendant with Black Opal

A Circle scribed on some carving wax and a black opal
Here we are making a small sterling silver pendant to contain a heart-shaped black opal. We begin by scribing a circle on a bit of carving wax. This circle will be the outside of the pendant.
Cutting the circle out of the wax
Then the circle is cut from the wax using a jeweler's hand saw and wax-cutting blade
A heart shaped bezel is carved into the circle of wax
A heart shaped bezel that will hold the opal is then carved into the wax using rotary tools in a flex-shaft machine as well as hand files
The Carved wax secured to the wax tree
The wax carving is then secured to a wax wire and placed onto a rubber flask base. The can on the left is a flask made of Inconel 625, a highly heat and corrosion resistant metal. It will be placed over the wax carving
The inconel flask around the carved pendant wax
This is the flask surrounding the wax carving
Pouring investment into the flask covering the wax
A bit of masking tape is secured to the top of the flask to prevent spills, and investment (a special high temperature plaster) is mixed and poured into the flask, completely covering the wax carving
Vacuuming the investment in the flask
The flask, filled with liquid investment, is then placed into a vacuum chamber and vacuum is applied to bring the investment to a boil at room temperature. This removes any small bubbles that might be in the investment.
The invested flask in the hot kiln
The investment is allowed to cure and then it is placed into the kiln and slowly, using a number of temperature steps and holds, is brought up to 1350 degrees farenheit. After soaking at 1350F for an hour, the flask is slowly cooled to 900 degrees and is ready for casting.