White and black metallic paints can be mixed to achieve a silver color. Using regular paints will result in a gray color because it will not have reflective qualities.
Other colors will also create a gray color (or silver color if metallic paints are used). Refer to a color wheel and use colors that are located opposite each other, such as yellow and violet, then add white until the desired tint is obtained. Metallic silver paint is also readily available online from various merchants. Silver paint can be used for such things as decorating crafts, painting artistic masterpieces, lettering wedding invitations or even painting a car.