Some bodies cannot be fired to even near zero porosity

Wednesday 13th May 2009

insight-live.com/trouble/11">Bloating in a high iron raw clay ground to 42 mesh (Plainsman M2). It is still stable, dense and apparently strong at cone 4 (having 1.1% porosity). But at cone 6 (top bar) it is bloating badly. At cone 5 the clay experiences the early stages of bloating. Cone 4 is thus "dangerous territory" for this particular clay. A reminder of this can be seen by putting on a transparent glaze - it fills with clouds of micro-bubbles from off-gassing that has begun well below cone 4.

Pages that reference this post in the Digitalfire Reference Library:

Terra Cotta, Vitrification, Clay Body Porosity, Bloating, Over Firing of Ceramic Glazes and Bodies

This post is one of thousands found in the Digitalfire Reference Database. Most are part of a timeline maintained by Tony Hansen. You can search that timeline on the home page of digitalfire.com.