How to make a Tibetan singing bowl?

The Tibetan singing bowl is made from mix raw metal alloy (copper, zinc, tin, iron) in open furnace with an exit orifice and heating temperature of 1083 degree Celsius. After this remove hot melted alloys from the crucible and use a dice to pour the hot liquid into a sand mold. Take the round metal sheets and roll and turn by hand beating or hammering to the desired size, weight and thickness of the tool.