How to test if an engobe fits a clay body

Thursday 5th June 2014

This is part of a project to fit an insight-live.com/glossary/35">engobe (slip) onto a terra cotta at cone 02 using the EBCT test.
Left: On drying the red body curls the bi-clay strip toward itself, but on firing it goes the other way!
Right: SHAB test bars of the white slip and red body enable comparing their drying and firing shrinkages.
Center back: A mug with the white engobe and a transparent overglaze. The slip is going translucent under the glaze because it is too vitreous. Its higher fired shrinkage curls the bi-clay bars toward itself. Reducing the frit will reduce the firing shrinkage and make it more opaque (because it will melt less).
Front: A different, more vitreous red body (Zero3 stoneware) fits the slip better (the strips dry and fire straight).

Pages that reference this post in the Digitalfire Reference Library:

EBCT Engobe Body Compatibility Test, Solving a difficult engobe flaking problem, Bi-Clay strips test compatibility between engobe and body, Creating a Body/slip Equilibrium in Terra Cotta Ware, Absolutely jet-black cone 6 engobe on M340, Ceramic Slip, Majolica, Engobe

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.