Nodular cast iron (BTN) or ferro casting ductile iron (FCDI) has high tenacity and strength. the composition in standard grade is generally as follows: C 3.2-3.8, Si 2.0-3.6, Mn 0.3 (max), P 0.02 (max) S 0.01 (max), Mg 0.03-0.06. The tensile strength standard is 400-800 with elongation of 2-15%. Wet sand molds used in metal casting scales below 100kg have moist properties and on the surface of the mold must be given water repellent powder first before pouring molten metal. Dry sand molds used on large scale metal casting above 100kg are made using organic binder, and then the mold is given CO2 gas pressure to strengthen the mold and harden the mold cavity surface and release other gases that are still present in the print sand blemishes. The process of heat treatment of cast iron can affect the properties of the cast iron. The best cast iron material for making weaving machine gears is the result of using wet print sand media by quenching the oil at a temperature of 525.90C, tensile stress value of 451.1 MPa, strain 1.57%, modulus of elasticity 335.5 Print sand media wet get better results, the sand material used can fill the small cavity in the mold and the resulting defects are smaller.