Underglaze color mayhem at cone 5!


Wednesday 5th November 2014

These are commercial insight-live.com/glossary/92">underglaze colors fired in a flow tester. Underglazes are not pure stains, they are a blend of stain powders with a host recipe (a porcelain-like mix of clay, frit, silica) that matures enough to fuse to the body but not so much that it melts. The blue, green and red are from one manufacturer. Stain powders have different melting temperatures and require differing percentages to get color intensity, the base recipe of the medium should compensate for that. That is not being done here, the pink one needs less flux and the green needs more. The black underglaze (D) (from a second manufacturer) has liquefied, gassed out and is about to head down the runway! The E black (a third manufacturer) has not even started to melt or even sinter. The black engobes were plastic, the colored ones were not, likely an indication that black requires a much lower stain percentage in the engobe recipe.

Pages that reference this post in the Digitalfire Reference Library:

Our own black underglaze better accepts the clear overglaze, Underglaze, Reverse Engineering an Underglaze, Bleeding colors


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.