Stearic acid is useful as an ingredient in making candles, plastics, dietary supplements, oil pastels and cosmetics, and for softening rubber. It is used to harden soaps, particularly those made with vegetable oil. Stearic acid is used in aerosol shaving cream products.Stearic acid is also used as a parting compound when making plaster castings from a plaster piece mold or waste mold and when making the mold from a shellacked clay original. In this use, powdered stearic acid is dissolved in water and the solution is brushed onto the surface to be parted after casting. This reacts with the calcium in the plaster to form a thin layer of calcium stearate which functions as a release agent.Esters of stearic acid with ethylene glycol, glycol stearate and glycol distearate, are used to produce a pearly effect in shampoos, soaps, and other cosmetic products. They are added to the product in molten form and allowed to crystallize under controlled conditions.In fireworks, stearic acid is often used to coat metal powders such as aluminium and iron. This prevents oxidation, allowing compositions to be stored for a longer period of time. It is used along with simple sugar or corn syrup as a hardener in candies. In compressed confections it is used a lubricant to keep the tablet from sticking to the die.It is used with zinc as zinc stearate as fanning powder for cards to deliver smooth fanning motionStearic acid is one of most commonly used lubricants during injection molding and pressing of ceramic powders.Stearic acid serves as an epilame (or barrier film) treatment, applied to precision mechanical components to modify the surface properties to reduce the spreading (or creep) of subsequently-applied lubricant films.