Core Vessel Technology: A New Model
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Core Vessel Technology: A New Model Dudley F. Giberson, Jr. P. O. Box 202, Warner, NH 03278 ABSTRACT Ancient Egyptian XVIII Dynasty core vessel manufacturing technology had many sequential steps to make a core vessel, but there were only three essential elements to the process. One, the base layer of glass was applied as a fritted powder; two, the objects were manufactured over a vertical heat source; and three, the vessels were made in very low temperatures (maximum of about 800°C). INTRODUCTION Present glass practice has changed little over the last 2000 years. It involves heating the glass batch to at least 1260°C, melting the batch ingredients at that high temperature for a few hours, then fining the product by dropping the heat to a lower temperature (around 1100°C). After some time, the glass absorbs the smallest gas bubbles. It is then ready to gather and blow. A blow iron is dipped into the pot and twirled to make a gather that is immediately blocked to cool the surface. Then a bubble is blown into the molten mass. The developing glass object is repeatedly heated in the glory hole and shaped until it is artistically correct. This sequence of motion is very efficient, for it takes but a few minutes to fashion a complete glass object. To understand ancient glassworking, we must leave all these glassblowing ideas behind. We must travel with our minds to a time before the invention of the blowpipe to a place where people had no concept of massive amounts of fuel required to maintain large amounts of fluid glass. In mid-second millennium B.C. Egypt, people did not have access to large forests. The fuel sources would have included dung, straw from grain cultivation, woody plants, some wood from banks along watercourses, and wood imports from elsewhere. The demands on fuel would have been great, and many crafts and other activities would have vied for its use. At this ancient time faience had been the first royal ceramic art and was used to decorate the walls of and objects within palaces and tombs. Faience workshops enjoyed imperial patronage where workmen crushed quartz to a powder, then mixed the powder with copper salts and plant ash or natron. This mixture was packed into damp ceramic molds, removed, and set to dry. As they dried, salts effloresced. The delicate faience objects were placed within a kiln and fired to a temperature (possibly as high as 980°C), sufficient for the salt layer to fuse with some of the underlying quartz to form a layer of copper blue glass. After firing, the faience was substantially stronger; the quartz particles were then held together by the glassy matrix. By 1500 B.C. this faience art was at least 1000 years old. Shortly after 1500 B.C., and with no developmental period, glass core vessels began to be manufactured in Egypt. The technology probably was imported from Mesopotamia, for there, especially in a place like Nuzi, a great deal of glass experimentation had taken place. It is important to realize that glass was probably worth its weight in gold, and was traded in i
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