Investment casting works by pre-applying coatings to the pattern—before investment casting mold creation, or to the mold—once it is fired. This serves several important purposes. Refractory coatings are applied to the interior surface of the mold to provide a barrier between the mold material and the molten metal. This reduces oxidation, contamination, and marking. An internal stucco layer in the mold can improve the release and texture of the surface to improve cosmetics by concealing slight flaws. Parting compounds applied to the mold surfaces ease the release of the casting at breakout.
Thermal barrier coatings applied selectively to the pattern can control the cooling rate and prevent rapid solidification. Anti-penetration coatings applied to the pattern can reduce the penetration of melt into the refractory material, to improve the quality of the surface finish.
