The metal powder is mixed with Multi-Purpose Resin, and hardener. This mixture is then painted into the mould as a first layer or gel coat. It is then either filled solid with resin and filler or laminated with glass fibre. When polished to reveal the metal, the castings are almost identical in appearance to a cast piece in the chosen metal. The metal content of the metal / resin mix should be as high as possible; too little metal filler is as bad as none at all.
Cold Cast Resin Metal pieces in Aluminium, Bronze and Copper can be polished or patinated
Quantities of Fillers: In general, a rule of thumb is equal parts by volume plus a little more filler (based on Multi-Purpose resin at room temperature).
A guide to weight ratios of metal fillers to one part of Multi-Purpose resin is:
Aluminium: 1¼ %