温度・粘度
Plate Count Effect
Japanese: 枚数効果
A phenomenon in which the behavior of shape change after firing varies depending on the number of glass sheets. A single sheet shrinks, two sheets retain their shape, and three or more sheets flatten under their own weight.
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The Plate Count Effect is a phenomenon in which the behavior of shape change after firing varies depending on the number of glass plates stacked on top of each other. Rei Chikaoka (2021, p. 153) articulated this practical design rule, which states that when fired as a single sheet, the glass appears to shrink due to surface tension; when fired as two sheets, the apparent size remains nearly the same (shape retention); and when three or more sheets are stacked, the glass spreads out due to gravity (self-weight flattening). This is an important fundamental rule for predicting the shape of glass sculptures created from a single mass of glass.
This phenomenon can be explained by the balance between surface tension and the weight of the glass (gravity). When glass is in a molten state, surface tension acts as a force that causes it to contract into a spherical shape; however, as the number of layers (i.e., weight) increases, the weight of the glass exceeds the surface tension, and flattening becomes the dominant process. This is a crucial design concept that directly relates to predicting the final thickness when stacking nine or more sheets in block fusing, as well as to understanding the need to minimize shrinkage in press fusing.
Related Concepts
Understand practical criteria for fusing design, including block fusing, press fusing, surface tension, and joint design rules.
This entry is written in Japanese by Rei Chikaoka and translated for readers outside Japan. If something reads oddly, the original is the source of truth.