Transparent glazes often work poorly on dark stoneware bodies

Sunday 2nd December 2018

These are fired in cone 6 oxidation. They are all the same insight-live.com/glossary/11">clay body (Plainsman M390). The center mug is clear-glazed with G2926B (and is full of bubble clouds). This dark body is exposed inside and out (the other two mugs have L3954B white engobe inside and midway down the outside). G2926B clear glaze is an early-melter (starting around cone 02) so it is susceptible to dark-burning bodies that generate more gases of decomposition - they produce the micro-bubble clouding. That being said, the other two glazes here are also early melters - yet they did not bubble. Left: G2926B plus 4% iron oxide. That turns it into an amber color but the iron particles act as a fining agent (vacuuming up the bubbles)! Right: Alberta Slip GA6-B. It also fires as an amber-coloured glass, but on a dark body, this is an asset.

Pages that reference this post in the Digitalfire Reference Library:

Thick application clouds a transparent glaze on a terra cotta clay, Is clear glazing a dark burning oxidation stoneware a good idea? Likely not., Two transparent glazes on the same dark burning clay. Why different?, Transparent Glazes, Clouding in Ceramic Glazes

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.