Chills are manufactured using mild steel or wire, generally are tinned or coated with wash, and can be produced in a variety of shapes and sizes. Nails, both horseshoe nails and straight shank nails, can also be used as chills. Chills are used to control shrinkage and achieve directional solidification when producing a casting. External chills are placed in the mold against the wall. Internal Chills are pushed into cores or the mold wall, therefore their mass protrudes into the mold cavity to achieve desired results.