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Published Sep 20, 2017

As we all know, in ceramics, trial and error is an integral part of the learning process—and often it can feel like mostly error. But it's the way it goes with this medium, and each little bit of wisdom these little failures yield, gets us closer to success

Peter Karner developed his surface decoration through years of trial and error and he continues to try new things so that his surfaces continue to evolve. In this post, Peter explains how intuition combined with experimentation helped him perfect his beautiful pottery glaze surfaces. Plus he details how he uses wax resist and layers of five different glazes to develop his gorgeous glaze patterning. - Jennifer Poellot Harnetty, editor

Developing Geometric Patterns by Layering Glazes

My pottery decoration is achieved by layering glazes and capturing carbon though reduction firing. I work with five glazes -- shino, carbon-trap, two types of copper saturate, and iron saturate -- all of which I apply differently to different effect. For the first layer, the pot is dipped in one of two glazes-either a shino or carbon-trap glaze. The second layer is a wax resist applied with a brush (I have experimented with several cold waxes and have come to rely on Forbes). The third layer is achieved by dipping the piece in one of two different copper saturates. As with my first-layer glazes, I've come to apply these two glazes differently. I've found that the amount of time the pot is in the bucket, the thickness of the glaze, and the suspension of the glaze particles all have a dramatic effect on the finished piece.


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For the fourth layer, I apply an iron saturate glaze with a brush. The fifth element, carbon trapping, I achieve in my downdraft gas kiln through a reduction atmosphere. Not all pieces attract carbon, which adds to the mystical quality of the atmospheric effect.

This process may sound relatively straightforward and scientific, but that is not the case. I work from a more intuitive rather than scientific place, and have managed to achieve my pottery glaze effects through years of trial and error. Every aspect of my pottery decoration has evolved over time. For instance, I noticed that my wax decoration was often not repelling glaze and that the "glaze sticking" seemed worse in the summer months when I had every window and door in my studio open. I deduced that the sticking either had to do with temperature and or wind/airflow. This led me to buy an air conditioner in order to regulate the temperature of the studio, and I performed a little experiment to see if my hunch was correct.

The first time, I shut up my studio and used the a/c during the decoration process only, leaving the studio windows open at night and between the first and second glaze-layer applications. I had just as much glaze sticking as ever. The next time, I used the a/c and kept the windows shut during the entire decoration process until the second layer of glaze was applied. The sticking problem was all but gone. It took me several cycles, adjusting my process each time, to completely resolve this issue.

This article was excerpted from the pages of Ceramics Monthly.

To see more of Peter Karner's work , visit



Topics: Gas Kiln Firing