Wax Carving and Casting Models
We work with a great casting company in Northern California. They cast in a variety of metals. The day we finished carving was one of the hottest days of the summer. And I worried that the waxes might be affected by the summer heat during transportation, but the casting gods were with us and they arrived unmelted.
To cast in the lost wax method, waxes are carefully attached or sprued to a treelike structure of wax that will eventually provide paths for the molten casting material to flow and for air to escape. To sprue you begin at base with a wax "cup," which is attached by wax cylinders to various points on the wax models.
The sprue is not hollow, as it will be melted out later in the process. This is done right before they are placed in a flask and made ready for the plaster pour. Once the plaster is poured - it sets over night. The following day it is placed in an oven to burn out the wax. Once the wax has left the plaster the flask is ready for metal. This is called the lost wax - process.