RBC offers a complete line of epoxy casting resins that can be used to duplicate any item, in conjunction with our GI-1000 RTV Silicone.

This system offers no shrinkage, no polishing, and no degating. These casting resins can be used to duplicate stones, mechanical parts, scrimshaw, and prototypes! The GI-1000 Silicone will pick up and retain the most intricate details of your model and is simple to use. Our epoxy casting resins and GI-1000 RTV Silicone are non-hazardous.

Open Pour Casting in Epoxy

Materials Needed

  • Aluminum Tray (cooking tray, deep enough to cover models)
  • Cardboard Mailer
  • Double-Faced Tape
  • GI-1000 RTV Silicone (see Silicone Molding page)
  • High Polished Models
  • Epoxy Casting Material/LV-7 Resin, AB-97 Hardener
  • Vacuum Jar
  • Oven or Warming Tray


Making the Molds

  1. Line bottom of aluminum tray or cardboard mailer with double-faced tape (enough to secure models).
  2. Attach high polished models to tape.  Models must have flat backs and be highly polished, without any imperfections.
  3. Mix GI-1000 RTV Silicone as directed.  Pour just enough to cover models.  Let sit for a minute so the silicone can release air.  Pour the rest of the silicone over the first pour, up to 1/4″ in depth over the models. 
  4. Mold should be cured 24 hours at room temperature before using.  For extended mold life, allow mold to cure 48 hours prior to use.
  5. Remove silicone mold from model after allowing it to return to room temperature.  

Making the Casting

  1. Preheat resin to 90°F.  Mix two parts resin to one part hardener by weight.  Stir gently for 2-3 minutes with a mechanical mixer.  Avoid whipping excessive amounts of air into mix!  Vacuum to remove any entrapped air.
  2. Place mold on warming tray.  Temperature should be set at 190°F.  Pour epoxy into corner of mold and allow material to flow throughout.  If you are not using a warming tray, place in oven at 100°F for 1-2 hours or until piece becomes hard.  Curing at higher temperatures will shorten the mold’s life.
  3. Remove pieces from mold after allowing it to cool to room temperature.