A sophisticated system of sprues, runners, and gates is decisive for the quality of the casting. The relationship of sprues, runners, and gates has to be adapted to the piece to be cast, the mold material, and the metal and casting temperature. Air that is displaced by the metal pouring in can escape through air channels.

Nails are inserted through the wax. When the wax has been burnt out, these supports for the core connect the core with the external form and thus keep it in the correct position. Since all nail holes have to be retouched later, as few nails as possible should be used.