The Irresistible Surface: Layering Pottery Glazes and Trapping Carbon to Create Loosely Geometric Repeating Patterns


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

by Peter Karner

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

  • Myra S.

    Peter, Your work is inspirational…I love the way you decorate your work !
    I just retired after 33 years as a Clinical Social Worker, but in all those years I have always been taking Ceramic Arts part-time at one college or another. I love to have my hands in Clay ! Lately I am experimenting in different ways to decorate my work. Thank You for sharing your techniques.

  • Marja G.

    I must say that when I receive mail from You my day brightens up. I have done my working days as a psychologist and now at 63 I started at a school for ceramists, it takes three yrs but i was directly tranferred to second year because I had been practising during my free time and can throw pieces that are ca 40 centimetres wide and love it. The only thing on your pages is that to order is possible only for U.S. residents and I am in Finland, Scandinavia, northern Europe.I enjoyed this page especially and shall try to work by the metheod.
    thank You so much

  • Chris L.

    I was awed, first seeing your work at the Cherry Creek Arts Festival a couple months ago. How fun, and fascinating, to now read about your experience and processes. Thanks!

  • Lindy S.

    Very inspirational pieces. I’m interested in how you started on this type of glazing and decorating and how you chose your glazes. I use glazes for decoration but the end result is quite different to yours.

  • Janet T.

    I am enjoying your combinations of forms, and then embellish them with your own surfaces. Yes, I’m going that way ! Thank you !

  • Rosa D.

    What is the brand of wax that you mentioned? Forbes? I’m not familiar could you provide more info?

  • Muriel W.

    This is an amature question. But, do you fire each glaze before the next glaze? If so, is there a problem with the next layer sticking to the fired surface? The vicosity has changed each time and I would think it would slip off the surface. MT in Sacramento

  • patti m.

    Hi Peter,
    I don’t have access to a gas fired kiln – only an electric kiln.
    Do you think it would be possible to obtain a similar carbon trapping effect in a raku firing?

  • Subscriber T.

    I also have done some glazes over each other. Have had some interesting results, but some of the glazes became very streaky and runny. How can you prevent the glaze on top causes the bottom layer to make bubbles while you glaze? I have also experienced that after firing, some glazes has pulled away from the claybody in certain areas. When you talk about cold wax, is that liquid furniture polish?

  • Sherman H.

    Dusty, there is no easy answer to that question. Whenever you combine glazes that are safe on their own (proven through testing at a lab, of course), you need to have the resulting combination tested as well. It is very difficult to guess how two glazes layered together are going to interact chemically (or even visually, for that matter) until you try it. If there is nothing harmful in your glazes, then it may not be toxic, but you will still want to know whether what you are firing ends up as a stable glaze, and testing what leaches out of the glaze is one of the best ways to find out.

  • It was great to have this email winging its way to me just when I was puzzling over how to decorate some new pots in my own unique way, and then up popped Peter’s very inspiring description of how he achieves such unusual work. He is proof that keeping your individuality and dedication to your work leads to something special. Thanks for the opportunity to see it.

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