To create a metal cold-casting, one-third by weight of the metal powder is mixed into two-thirds of a two-part polyurethane resin until the mixture is thick and creamy. Next, the mixture is either brushed or poured into the mold cavity (usually a silicone rubber mold) until the resin cures. If the gel coat is brushed in, it is backfilled with resin without the more expensive metal powder mix with it.
When first demolded, the casting will look somewhat dull. It must be properly burnished to bring out the metal luster.
For best results, Mineral Spirits, medium/fine steel wool, and shoe polish are used to bring out the most realistic effect. Begin by wiping down the entire surface of the model with a towel soaked in mineral spirits. The mineral spirits will temporarily soften the plastic slightly and make it easier to bring out the metal shine when buffing with steel wool.
Abrade the casting using medium/fine steel wool (0000) until the desired metal shine and luster is attained. Highlight the surface with black shoe polish to add depth and dimension. Allow shoe polish to dry then buff with a soft cloth. To prevent the oxidation of the metal, acrylic spray can be used to protect the finish. Spray the polished piece with two coats of semi-gloss acrylic spray.
Below is a comparison of ArtMolds' metal powders for cold casting available through Amazon.com