[Clayart] commercial clay/VITREOUS

[Snail Scott]

> On Apr 5, 2018, at 10:32 PM, David Woof <woofpots at HOTMAIL.COM> wrote:
> Just a reminder from a word "nit picker"... "Fully Vitrified" would "**Most Likely**" (lawyer PMA) pluck, slump, or depending on the form, sag and or sag and crack open in a slumped ragged tearing of the wall.


It’s a valid point. However, I prefer to apply a broader definition. 

‘Full vitrification’ is an absolute condition meaning entirely glassified, but in actual use, it’s is a relative concept. For working purposes, I define it as ‘as fully vitrified as a particular clay body is capable of becoming without incurring the various defects associated with overfiring’. By this usage, full vitrification of an earthenware body would still have considerable absorption, as further firing would result in slumping, bloating, etc., while full vitrification of a porcelain would have an absorption of near zero if stopped just short of warping and slumping. Of course, some forms will slump more readily than others, so it’s still relative, not just to the chemistry of the body but also the structural properties of the form.

Snail Scott
claywork at flying-snail.com
www.snailscott.com