MET 110 Course Modification - Glass Pendants
Creating a glass pendant requires a combination of introductory glass working skills and understanding of the glasses being used. The students learn about the importance of proper eye wear, glass materials properties (melting/cooling and thermal shock), material selection, and creative opportunities to individualize the project within the pendant making process.
Students had a lecture based on color theory and were taught the steps to manipulating materials and creating pendants.
Prior to experiencing the the glass pendants project, student had a technical lecture based on color theory, rheology (the study of flow), temperature dependence, and were taught the steps to manipulating materials into a desired shape and creating pendants. Figure 1 and 2 show the steps to create a pendant.
Figure 1: Diagram created by an undergraduate student leader, Jenna Sayler, demonstrating steps to creating a glass pendant.
Figure 2: Jenna Sayler, leading the students through the steps and discussing safety requirements for the project.
The students heated the glass road to a molten state. A molten state describes the process of liquefying a material by heat, specifically materials with a high melting point - such as metal and glass. By heating the end of a glass rod in the torch to temperatures of ~1500 °C. Glass does not transfer heat in the manner that a metal does, allowing the students to hold the end of the rod that is not in the torch flame. Images Figure 3 and 4 are the students heating the glass to a molten state to be able to gather the end into a ball.
Figure 3: Students heating the glass rods to be able to gather the glass at the end. The roundness of the sphere is visible in the torch closer to the marker board.
Figure 4: Jenna Sayler, demonstrating the rolling technique that requires continuously rolling the rod to not have the gathered material slump or fall off of the rod.
Along with practicing their rolling technique, the students used graphite molds to help shape the molten end into a spherical shape, Figure 5 and 6. Graphite molds are used in many hot glass and metal working (shaping, flattening, see Figure 7) processes because they can withstand the thermal shock. Thermal shock is a form of rapidly transient mechanical loading (caused by rapid change of temperature). An example would be pulling a glass dish out of the oven removing the food and then running cold water over the hot glass. "Cooling" the glass dish can cause thermal shock resulting in the glass could shattering due to the drastic change in temperature.
Figure 5: Students shaping the molten glass in a graphite mold.
Figure 6: Student examining the the gather after shaping in the mold.
Figure 7: Jenna showing how to press the sphere into a flat pendant shape.
Having created a smooth sphere that was then pressed into a flat pendant shape, the students will then be able to begin the color integration stage, Figure 8 and 9. Color integration is an important technical and artistic step. Stringing, extensional flow of the molten glass, can occur when integrating glass, Figure 9 and 10. The material used for the clear rods must be the same as the colored rod material otherwise the glass pendant can break as the two materials may have different coefficients of thermal expansion. The coefficient of thermal expansion is how much a material expands upon heating. If materials are very different and expand (or contract) differently this can cause stress within the materials.
Figure 8: Color integrated sample created by Jenna as a demonstration for the MET 110 students.
Figure 9: A MET 110 student successfully integrated color into the clear glass pendants.
Figure 10: Stringing of the hot molten glass. This stringing can occur with the colored glass as well.
After successful integration of color into the pendants need to be very slowly cooled, annealed. This is done by placing the piece in a crock pot filled with kitty litter to allow the glass to slowly cool. Cooling too fast can cause the glass to fracture.
Figure 11: A finished product of glass pendant prior to being placed in an annealer.
Figure 12: The glass piece was placed in the annealer to slowly cool and later be displayed.
Figure 11: Final product created by Jenna as a demonstrative piece for the class and STEAM outreach.
