Powdered metals used as fillers result in castings with a realistic metallic finish.
They are used in the same way as filler powder, pt the resin is catalysed BEFORE adding the powder,this is to neutralise the catalyst, which would otherwise have a corrosive effect on the metal.
For metal castings, always use 2ml catalyst per 100g resin. The higher proportion of the metal to resin, the better the finish.
Generally speaking, a 50/50 mix, by volume, is a minimum ratio. For every 100g of bronze powder you will produce approx 20ml in volume.
The finished casting will not look very metallic – the surface will be dulled by a thin layer of resin. Removing this surface layer by buffing with wire wool then metal polish produces the realistic metallic sheen.
Different metal powders can be mixed together if required – mixing aluminium and a little brass, for example, produces a good simulation of old tarnished silver.
The powders should be mixed before they are added to the resin.
Graphite powder rubbed onto the finished casting will also give a “aged” effect. A better effect can be obtained by mixing the graphite with the metal powder (1 part graphite to 10 parts metal, by weight) before adding to the resin.

Easy to use RTV silicone rubber have excellent release properties, which makes production casting of resins (polyurethane, polyester, and epoxy) quick and easy. No release agent is required for nearly all surfaces (although silicone will bond to itself) and for all resins poured into it. These silicones also exhibit good chemical resistance and high temperature resistance (over 200 °C). For this reason silicone molds are suitable for casting low melting point metals and alloys