before that the ten disk cores are placed in a casting box the cavities are filled with special sand without this sand parts of the mold would fly off during casting it's a job which calls for a lot of experience any mistake could render the mold useless all this takes place days before the actual casting which also demands total precision the clock is ticking the molten mass is cooling by the minute so the smelters have to check its temperature time and again on no account must have dropped below 1,400 degrees