Will this crawl when fired? For sure!

Wednesday 25th February 2015

This high-Alberta-Slip glaze is shrinking too much on drying. Thus it is going to crawl during firing. This common issue happens because there is too much plastic clay in the glaze recipe (common with slip glazes). Clay is needed to suspend the other particles, but too much causes the excessive shrinkage. The easiest way to fix this is to use a mix of raw and calcined Alberta Slip (explained at albertaslip.com). The calcined Alberta Slip has no plasticity and thus much less shrinkage (but it still has the same chemistry). Many matte glazes have high kaolin contents and recipes will often contain both raw and calcined kaolin for the same reason.

Pages that reference this post in the Digitalfire Reference Database:

Ravenscrag Slip, Alberta Slip, Alberta Slip 1900F Calcined, Alberta Slip 1000F Roasted, Crawling, Calcine, Calcination

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.