While crazing is classified as a glaze defect, it can also be corrected by adjusting the clay body. The goal is to adjust the glaze and clay body to cool at a compatible rate with the glaze coming under slight compression.
Like anything that’s been around for thousands of years, the combination of science and art that is pottery has built up an enormous amount of folklore and superstitions. Jeff Zamek separates fact from fiction.
Since pottery is an endeavor that involves many steps—any of which can cause total failure—potters often misguidedly cling to a set method or technique that they think will provide a guaranteed result.
The making of ceramic objects is, at best, part science and part intuitive art. In the past, the basic science of pottery production was somewhat hit or miss. Without an extensive understanding of the underlying theories concerning ceramic materials, potters were often left with myths and inaccurate information on forming techniques, glaze formulas and firing processes.
When creating a stoneware clay body formula, one of the most important characteristics is plasticity. The unique attributes displayed by clay/water structures contribute to the plastic qualities of moist clay.
With a move toward leaner, more efficient manufacturing processes, the basics of glaze formulation and application should not be overlooked.
March 1, 2005
Over the past decade, and especially within the last several years, many manufacturers of tile, dinnerware and sanitaryware have begun embracing leaner, more efficient production processes in an effort to remain competitive. As part of these initiatives, some companies have installed new glazing equipment, modified existing kilns or installed new kilns to optimize energy efficiency, developed new glaze and body formulations, investigated and/or implemented new glaze application processes, developed specially treated glaze materials, or combined different application processes (such as dry/wet) to produce new effects. While these are all important steps, the basics of glaze formulation and application should not be overlooked.
Quality and consistency are key criteria for any clay body. Without the right shrinkage and absorption, workability, glaze fit, and durability, your final product will likely be headed for the reject pile.
By understanding the differences and similarities between the various kiln designs, ceramic manufacturers can be better prepared to make the right selection for their plant.
May 1, 2003
It’s time to buy a new kiln. You open Ceramic Industry’s annual Data Book & Buyers’ Guide to find a kiln, but suddenly you feel overwhelmed by the different selections available. Do you need a bell, belt-type, or bending and convexing kiln? Or do you need a box, calcining, conveyor-type or decorating kiln? Maybe you need an electric, elevator, envelope or fast-firing kiln. Or maybe your best bet is a gas, infrared, high-temperature, laboratory, periodic, pusher-type, roller hearth, rotary or tunnel kiln. How do you choose?
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