This class was an Introduction to Lost Wax Casting. The following is a "reader's digest" version of the steps involved in the Lost Wax Process. I could go into much more detail, but will do that in another section.
Now, with two wax patterns ready to cast we moved on the the next phase of the process. The "sprueing". This part of the process is how the wax patterns are attached to the "sprue base". The sprues are also how the wax "gets out" and the molten metal "gets in". The sprue base is a flexible rubber base that fits a steel flask. Because Rich wanted to do the cat in gold and the ring in sterling he sprued each wax separately so that they would be in they own flask.
Once the wax patterns are attached to the sprue base, and a "debubblizer" is sprayed on the waxes, the flask is placed over the patterns and it is ready for the next step in the process. Which is the investment phase. "Investment" is the name of the "Plaster mix" that is used to encase the wax patterns. Once the plaster (investment) is poured into the flask it's set aside and allowed to cure or harden. After about an hour it's completely cured/hard. Then the flexible rubber sprue base is removed, with a twisting action. This leaves a corresponding negative depression in the bottom end of the plaster filled flask. All that is visible of the wax patterns is the end of the wax sprue that was attached to the rubber sprue base. The next phase of the process is to preheat the kiln to 350 degrees and prepare to melt out the waxes. At the lower temperature the wax melts into a "wax tray" that catches all the wax and can be removed before the kiln is taken to the higher burn out temperatures. This is how the process gets it's name, Lost Wax Casting. By melting out the wax pattern......it is Lost. And leaves a negative in the plaster that will accept the molten metal, and reproduce the wax master in the metal of choice.
When the metal is molten and "fluxed" the flask is removed from the kiln and placed on the vacuum casting machine. When the casting machine is turned on, the the molten metal is poured into the depression left by the sprue base and the molten metal is "sucked" into every crack and cranny of detail that was on the master and is NOW in the negative space in the Plaster. There by creating an Exact copy of the wax master. This casting process was repeated for the other flask and then we proceed to the "break out" stage. This is done when all the heat is gone from the "molten sprue button" that is visible in the depression in the flask. Once you can no longer see a Red Glow from the molten "button" you can take the flask and submerge it in a bucket of water. This makes the hot investment react with the water, it boils radically causing the plaster investment to break apart and fall off of the still hot casting. This makes the clean up a lot easier than trying to break off the cold plaster investment. That is the end of the casting process.
The only think left to do is to clean up the castings. This involves cutting the cat and ring off of the sprues and filing and buffing to the desired finish.
As you can see in the finished jewelry photo above, Rich also made a small anvil pendant by carving a negative impression in a charcoal block. He carved an anvil, which he filled by melting the sprue and button that was left over from casting the cat. Not a great photo but... shows him working and the very "basic" carving tool that he used. The working "end" is like a flat screwdriver.