Aluminium Stearate, available in High Gelling and Non-Gelling grades is an important industrial Stearate.

Aluminium Stearate is a white, wax-like powder (metallic soap) that dissolves in mineral spirits or hot oil. A small amount (2% or less) added to oil paint imparts a short, buttery consistency. It eliminates the separation of pigment and oil, thickens varnishes considerably. A concentrate of Aluminium Stearate and linseed oil can be prepared ahead of time and added to the paint whenever needed.

Aluminium Stearate is made via the precipitation process using high quality Stearic acid and exhibits the following properties: Good gelling and thickening action, excellent water repellency, transparency and a synergistic effect with Zinc Stearate or Calcium Stearate.

The effects of metal soaps on pigments have been extensively proved in case of Aluminium Stearate. It was found to coat the surface of pigment particles and helped prevent settling as well as reducing the amount of oil needed to wet the pigment. The amount of Aluminium Stearate needed to coat pigments varied on a weight basis, but a solution of 2% by weight (weight of Aluminium Stearate/weight of oil) of Aluminium Stearate was more effective than 0.5% or 4% solutions in altering pigment surfaces. The soaps coat the surface of the pigments and by steric effects keep the particles from aggregating, which helps to keep the particles in suspension.

With increasing amounts of Aluminium Stearate the oil pigment mixture becomes viscous, and by using an appropriate amount of Aluminium Stearate the paint can gel at a lower pigment concentration. This can be used to create a "cheaper" paint since a smaller amount of a costly pigment needs to be used. A significant advantage of using Stearates is that the oil and pigment do not separate greatly over long periods of time in the paint tube. Manufacturers of artists' paints often use Aluminium Stearate in their formulations without listing it as a component on the product label.

Aluminium Stearate dissolves in vegetable oils on heating and if a high enough concentration of the soap is used, gelling occurs on cooling. In the usual practice of making paints, the Aluminium Stearate is ground with the pigment before the bulk of the oil is added. To prepare a concentrated solution (10%), add 200 grams of Aluminium Stearate (nearly fills a one litre measuring cup without compacting) to one litre of linseed oil. Heat the oil to about 150° C. and gradually slowly adding the white powder to the hot oil with stirring. Add one part of this solution to four parts of oil by weight of oil before adding to pigments and grinding.

Aluminium soaps have different and widespread applications, Aluminium Stearates being especially important among them. Aluminium Tristearate is useful in paints and enamels and in the flatting of varnishes. It also prevents bleeding and oil separation in putty. Aluminium Distearate is the most commonly used grade of Aluminium Stearate.