Metal Cold Casting With Smooth‑Cast® 325 Resin


"Cold-Casting" is a term used to describe the process of mixing metal powder with a resin to create castings that give the appearance of solid metal. The metal cold-cast process (also known as "bonded bronze") is faster and much less expensive compared with foundry casting of molten metal (lost wax process.) Different metal powders such as Bronze, Brass, Nickel Silver, Copper and Aluminum can be used depending on the desired effect.

To make a metal cold-casting, metal powder is mixed into the resin until the mixture is thick and creamy. The mixture is then brushed into the mold cavity until the resin cures. The gel coat is then back-filled with straight resin, resin mixed with metal powder, resin mixed with lead shot (for weight) or Foam-iT!® 5 rigid foam to yield a light weight casting.

Specifics - Cold Cast Bronze Example - This step-by-step example will detail making a cold-cast metal casting using bronze powder. A "gel coat" layer is applied first to the rubber mold cavity. More resin is then poured directly on top of the gel coat (back filling.) The gel coat and back fill mixture is allowed to cure. The cured resin casting is removed from the mold and the bronze effect is brought forth by buffing the surface with steel wool.

Materials Used in this Tutorial

  • Smooth-Cast 325
  • OOMOO 30
  • Ease Release 200
  • Ease Release 205
  • So-Strong Color Tints
  • Metal Powders
  • Paint Brush
  • Paper Clip
  • Mixing Containers
  • Mixing Sticks
  • Towel
  • Mineral Spirits
  • Medium/ Fine Steel Wool
  • Black Shoe Polish
  • Acrylic Spray