Glass

Chapter 1: The Hot Glass

• Introduction to Glass

  • Glass creation is a significant technological and artistic achievement.

  • Invented around 5,500 years ago, glass was once as valuable as gold.

  • Earliest known glass items include beads and vessels.

• Glass Making Techniques

  • Artists utilize hot methods, warm techniques, and cold processes:

    • Hot Methods: Include blowing and casting.

    • Warm Techniques: Involve fusing or slumping.

    • Cold Processes: Include cutting, sandblasting, and grinding.

  • Example: Dale Chihuly's Fiore Tacoma uses glass blowing.

• Glass Blowing Process

  • Glass is heated to 2,150°F and gathered onto a blow pipe from the furnace.

  • Gathered glass is inflated by blowing into the pipe and shaped with tools like wooden blocks and wet newspapers.

  • Glass is reheated in the glory hole to facilitate shaping.

  • Surface coloring can be achieved by rolling glass in or sprinkling it with powdered glass.

  • Once shaped, the glass is transferred to a punty for final shaping and cutting.

  • The finished product is placed in the annealing oven to reduce stress and temperature.

  • The process requires experienced teamwork.

• Cast Glass Objects

  • Molds are formed using sand or a plaster and silica mixture called investment.

Chapter 2: The Hot Fused Glass

• Sand Molds

  • Sand molds often contain powdered bentonite clay for binding.

  • Water adjusts the mixture's consistency.

  • A template creates an impression in the sand forming a mold cavity.

  • Molten glass (2,350°F) fills the mold's impression.

  • The glass is transferred to an annealing oven after cooling slightly.

• Fused Glass Creation

  • Fused glass objects include vessels, tiles, and jewelry formed by layering heated glass in a kiln.

  • Tack fusing requires 1,250°F to 1,325°F; full fusing requires around 1,450°F.

  • Various tools can shape hot fused glass during the process.

• Slumping Technique

  • Slumping allows glass to sag into shape inside the kiln.

  • Molds assist in shaping as glass softens.

  • The Roman period saw slumping frequently used for glass vessels.

  • Slumping can be combined with the fused glass method to create artistic works.

  • Stained glass windows, like those at Schaller Cathedral, exemplify cold glass methods.

Chapter 3: Heavy Stained Glass Window

• Design and Template Creation

  • Artists draw initial designs, dividing them into templates for cutting individual glass pieces.

• Glass Cutting Process

  • Score glass with a cutting wheel, then break it using groziers for individual pieces.

  • Lead or copper kames (shaped like letters 'u' or 'h') are used to fit between glass pieces, securing them in place.

  • Kames are soldered one at a time to form the final design.

• Support for Heavy Windows

  • Metal rods may support heavy stained glass windows at intervals.

  • The combination of hot and cold methods can create artistic effects (e.g., Roman Portland vase).

• Artistic Expression

  • Glass artworks are inspired by its ability to reflect, refract, and transform light.

  • The beauty of glass encompasses many useful objects in everyday life.