Glass Mold Making

Types of Clay

  • Model Clay – Dark Gray – For Fine Detail Work, and fine line carving, , small shapes, etc
  • Ceramic Clay – Reddish – For Coarse work, larger shapes, etc
  • Mold-making Oil Clay – Yellow – Doesn’t Dry, For Continual Shaping & Re-shaping when Making Molds

Procedure:

  • Carve your Object Model Out of Clay
    • 2 types:
      • Objects with a Flat bottom and a form smaller than the bottom that can be removed from a mold directly
      • Objects with complex shapes that do not have a flat bottom, or that cannot be directly “uncovered” by the mold without losing shape or being damaged, etc
  • Add All Details to Clay, and make it as smooth as possible, as much like the finished glass object as possible
  • Set it on top of the Yellow Mold Oil Clay so an equal portion is facing up and down
  • Place more yellow mold clay around the clay model, against its edges, all the way around
  • Using a small drill-bit head, scrape the yellow clay to the exact mid-point on the side of the clay model
  • Press indented holes in the yellow clay around the edges at even intervals, for lining up both halves of the mold (if using a big-bottomed model, you dont need holes and can just cover the entire thing in Silicone Latex)
  • Cut the mold clay into a prefect square
  • Build walls around the mold clay with more mold clay or PVC sheets, wood, etc, about 3 cm above the top of the model
    • Use a hot glue gun to seal off all joints if using sheet panels of pvc
  • Fill the box with Liquid Latex which has been mixed vigorously with setting agent
  • For bigger items, place a layer of cheese cloth between layers of latex
  • Set for 3 hours
  • Remove the walls
  • Turn the model upside down and remove the mold clay, save for later use
  • Set the walls back around the model and silicone base
  • Coat the silicone with an oily white hand cream
  • Fill again with Silicone and leave for 3 hours
  • Remove Walls from all sides of silicone
  • Separate Mold and remove all clay
    • If you have a 2 piece mold that you poured all at one time, you can simply use a blade to cut midway through the silicone, cutting the clay model in half as well, but only cut about 70% through the silicone, not completely in half, then get all the clay our, and wash the mold thoroughly
  • Wash inside the Mold with soap & water well
  • Melt Hard Green Sea Green Casting Wax
  • Cut a fill hole near one end of the mold
    • its a good idea to cut a smaller secondary hole on the same side next to the first hole, to let extra trapped air escape during filling
  • Tape the silicone mold together, or use rubber bands, or blocks, etc to hold both sides air-tightly in place
  • Fill the mold with the Hot Sea Wax, using a Large metal Ladle with a small Pour Spout on one side
  • Let it Cool for at least one afternoon
  • Carefully unwrap and Remove Silicone, save for later use
  • Carefully trim up and finish the Hard Wax Model to be Exactly as u want the finished model to be
    • Use a small wax cup heater with wide rounded metal rim
    • Heat metal carving tools in the wax and rub excess wax off on the wide rim
    • Tools can be heated directly by rubbing them on the hot wide metal rim
    • Use a special metal tool with one flat 1/4″ blade on one end, and a thin crescent 1/3 round blade on the other end
    • Use wooden carving tools
    • Add wax to build features, as needed
    • Scrape off wax as needed
    • Spray cool water to make the wax harder and stiffened for more smooth finishing scraping
    • Build a Plaster Mold around the Plastic Model – (details to be added later)
    • High-heat Plaster
    • Lower Heat Plaster
    • Let harden Completely
    • Melt the Wax in a Hot Steam Box or similar, and Pour out the wax, save for later use
    • Fill the Plaster Mold with Molten Glass, and set in a temperature reducer until done

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