Gradient bars show the degree of vitrification of a clay

Friday 27th October 2017

These are the fronts and backs of dust-pressed bars. After final drying the width at each line is carefully recorded. They are fired horizontally in a furnace able to reproduce linear thermal gradients along the length of the bar. Thermocouples monitor the temperatures along the bar, so the temperature reached at each line is known. After firing the widths are re-measured, this produces a graph of fired shrinkage vs. temperature. Clays can be visually inspected side-by-side and differences or changes in maturity are immediately obvious.

Pages that reference this post in the Digitalfire Reference Database:

Orton Gradient Furnaces, Maturity, Firing Shrinkage

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