Should the flasks be dry or steam dewaxed?
Either. The most important thing is that the flasks are completely free from wax residues at the time of casting. 13 Do I need a different furnace? This is one of the most critical points of the process. Firing with natural stones requires a lower burnout temperature (maximum 630°C/1166°F) and this can give a poor burnout. Any carbon residue from the wax left on or adjacent to the stones can lead to burning of the stones and so it is vitally important that there is a good air flow through the furnace during the burnout procedure. This is easy to achieve in gas fired furnaces but electric furnaces may need extra ventilation holes drilling through the brickwork at the bottom or through the door. It is also important that air can flow underneath and up through the flasks so do not stand them directly onto a solid floor. The burnout cycle for synthetic stones is exactly the same as plain gold and so no changes are needed to the furnace. 14 What temperature should be used in the burnout fur
