A brief non-technical introduction to the vacuum casting process at Precious Ghost. Sarah and Cicada will walk you through the steps. Though we make it look easy, the process does take some time.
So you’ve chosen your stone and setting. At this point we will have sent you a CAD rendering of your design for your approval.
Your ring is then 3D printed
We sprue the ring onto what is called a “tree”. Typically we would have several items on the same tree for each metal casted.
The investing process creates a mold around the ring that was just sprued up. The metal sleeves full of holes are called “flasks”.
After a few hours allowing the investment to set we place it in the kiln and begin the burnout process. Temperatures ramp up gradually as high as 1350 F over the course of 10-12 hours.
We’ve already weighed the wax and calculated how much gold we will need for casting. We typically need 15-20 extra grams of gold that serve as the “button”.
We heat the gold up to a very specific temperature for each metal in a crucible inside a melting kiln.
Once the gold is melted and ready to cast, we’ll remove the flask from the kiln and place it in the vacuum casting machine.
I guess you could say this is the fun part. We take the hot AF crucible and pour the metal into the flask. As we do this the vacuum is pulling the metal down and through the hollow cavity left by the wax before burnout. A big healthy button leads to a successful cast!
After cooling down 30 seconds, you begin the see the crystalline structure of the gold.
We wait 5-15 minutes before we can quench the flask in water. The crucible is still very hot and the water boils.
We clean the investment off the casting
We saw or clip the individual pieces off of the tree and begin filing, sanding and cleaning up the castings.