Glazes - for the Self-reliant Potter (GTZ, 1993, 179 p.) 1. Introduction and scope (introduction...) 1.1. Glaze making using local materials as far as possible 1.2. Glaze and clay systems

Glazes - for the Self-reliant Potter (GTZ, 1993, 179 p.)

1. Introduction and scope

There are already many books in the world on the subject of ceramic glazes. So the obvious question is: why yet another book on the subject? The authors have worked together for several years in a ceramics development project in Nepal, which is based on using local raw materials and resources. There are few existing books which offer much help in this area, especially working in the low temperature range from 900°C to 1100°C, where lead glazes have been the tradition but which now, with greater understanding of health hazards, need to be replaced with lead-free glazes. This book is intended to provide practical information for ceramists working in developing countries, with little access to the prepared and controlled glaze materials available in industrialized nations.

Glazes are at one and the same time the area of most fascination and most difficulty for potters. Most potters have little inclination or time to devote to developing glazes, faced as they are by the daily need to produce for the market. However, there often are times when familiar glazes suddenly stop working correctly or special glazes are required for customers. This book offers guidelines for developing and altering glazes, understanding where problems with glazes come from, and standard procedures for testing and developing glazes when there is no laboratory equipment available. It has been written for potters who have little knowledge of chemistry and mathematics.

1.1. Glaze making using local materials as far as possible

Most small producers of glazed ceramics will use glazes that are prepared by a company specializing in supplying industry. However, these glazes are often unreliable, as big companies tend to serve large-scale producers and have little interest in the special glazes needed by small industries. For that reason, the small producer is often forced to rely on his own glaze production, with little or no laboratory equipment available. Additionally, the small producer does not usually have access to raw materials at reasonable prices, so he must use locally available raw materials that do not have an accurate chemical analysis.

1.2. Glaze and clay systems

The producer must think carefully before starting production. When a particular glaze is wanted, it must work with the available clay body, production system and firing system. For example, if you only have low-temperature red clay available, your glazes must work at around 1050°C. If you only have coal available for firing, you must make sure that it will work for your product. The following chapters provide information which will help you to make these decisions.