Wet Color Pigments

Wet colors, or dispersions of color in liquid, can be used  easily. Dispersed colors can be added directly to the water for each mix of plaster. A very small quantity of color dispersion produces a fairly deep color intensity.

Regardless of the color used, putting color in the plaster will not produce a uniform shade of color in the dried cast. As the excess water migrates from the plaster cast, areas of light and dark color concentrations appear. Thus, the use of color in the plaster does not replace surface decoration, such as paints and lacquers.

Finally, the color used in the  plaster mix should be checked for its compatibility with the surface decoration that will be used on the plaster cast. If the color in the cast "bleeds" through the surface decoration, it creates problems. The vendor can provide information about this aspect of the color.

Color Pigment Information by

For more information on color pigments and custom blending, please visit "Blue Mountain Pigment" - The Home of Endless Color! Blue Mountain Pigment supplies the concrete and masonry industries with the highest quality service and custom-blended iron oxide pigments. We provide custom-packaged pigments in any color and quantity.

Dry Color Pigments

The use of dry color pigments to tint plaster casts is also feasible. First, be sure that the color pigment used will not adversely affect the plaster. Some color pigments may contain ingredients which accelerate or retard setting time of the plaster slurry or may cause excessive pinholing in cast surfaces. Second, use only enough color to get the desired end results and no more. Heavy additions of pigment impair the physical properties of the plaster cast. For example, additions of 10% dry pigment may deduce dry compressive strength by up to 30%, and dry impact strength up to 50%.

Dry colors are best handled by adding them to the water to be used for mixing the plaster. The pigment is completely dispersed in the water, either by stirring with a mixer in a ¼-inch drill or by mixing with a paddle. Any desired quantity of water can be pre-mixed with color pigment, then used as needed by each person in the cast shop. Since many dry color pigments are not water soluble, be sure to buy from a reliable source. Stir the colored water blend well before it is mixed with  plaster.