Layering glazes is a passion! If you engage in careful glaze preparation, skillful application, and detailed note taking, you can create a nearly infinite variety of combinations. If you stocked only five glazes, you could layer them in 18,515 different
ways! It should be noted, however, that color combinations do not work according to the traditional color wheel (e.g., red plus blue does not necessarily make purple). Additionally, the combinations of ingredients in the different glazes may intermingle
in interesting ways. For example, a combination of two matte glazes can run down the side of a pot. For this reason, always use a cookie and/or wadding underneath any new (or known runny) combinations to minimize the need for grinding and potential
damage to kiln shelves.
When layering glazes, first apply a base coat through dipping, pouring, brushing, or spraying. Allow it to dry to the touch before adding a second layer. The second and subsequent layers of glaze should be applied slightly thinner, either by using a shorter
count or by decreasing the specific gravity. I have found that it’s best to wait 2 to 3 hours before applying a third or fourth coat—sometimes even overnight. To play it safe on new combinations, aim for the second glaze to go no lower
than a third of the way down the pot and for the third coat to go no more than a quarter of the way down the pot. Once the degree of melt can be observed, you can adjust for the next firing.
When working with layering glazes, you may find that some glazes layer poorly, flaking off the glaze below it. A possible cause is a difference in clay content in the glazes. When a glaze with a high clay content is applied over a glaze with a lower one,
the glaze with more clay can tend to flake off when it shrinks. Reversing the order of application can solve the problem, but it will give a different look to the layering. Alternatively, you can try adding 1% CMC gum or 2% bentonite clay to the low-clay
content glaze. A glaze that has sat unused for some time and had a chance to flocculate may also tend to flake. If so, you could add one drop of the deflocculant Darvan 811 per cup and mix until the glaze noticeably thins.
Refiring at Cone 6
If a particular glaze emerges out of the kiln and displeases you, don’t be afraid to refire! This can take several forms at cone 6: previously salt-glazed, wood-fired, and high-fired work may be refired in oxidation to cone 6 either as-is or with
the addition of more glaze. Pieces may be fired multiple times to cone 6, or they can be fired to a lower temperature with the addition of lusters, decals, china paints, or other low-fire applications. The first glaze firing should be seen as just
that and doesn’t necessarily represent the end of the road. If you loved your piece before glazing but the glaze results make you want to chuck it in the dumpster or worse, it might be worth a refire.
Note that refiring will increase the amount of cristobalite in the clay body, and refired pieces can be more prone to dunting. Fire slowly, as refiring a glazed piece can cause it to explode in a glaze firing. I have only seen this once or twice, but
the shards stuck to the other pots in the kiln and the kiln shelf. However, the ability to save, rectify, or even improve the look of a sad pot can be worth the risk, and I must say, it’s immensely satisfying when you turn a badly glazed piece
around. My experience has been that refiring is generally a 50/50 proposition. Half of the time, the pot will look worse, but there are plenty of times when a refire will make you jump for joy.
Two-Glaze Combinations
Here’s where the fun begins! To get your bearings with any new set of glazes, you first want to test each glaze in combination with every other recipe in the set. For each glaze, I dipped ten of the tiles for a two-second count in the same glaze.
I then inverted the piece and dipped the top one-quarter of the tile in a different glaze. With eleven base glazes, I ran a total of 110 two-glaze combination tests to see how each glaze operated with every other glaze in the group.
The results of the two-glaze combinations tests were, as one should expect, not all spectacular. In fact, some of the tests were downright ugly by anyone’s standards! But this is important information. Knowing which combinations do not reflect your
aesthetic vision can be as important to honing your palette as knowing which ones represent you well.
In any case, these two-glaze combination tests will show you how the glazes perform with each other, including degree of runniness in each combination. You can use this information to make decisions about how much of the first glaze you want to show on
the outside of your pot. If a combination doesn’t move that much, you now know that you can dip the second glaze further down the piece to create a different look. Similarly, for the very runny combinations, you now know that you should keep
the second glaze toward the top of your pot to allow it to run.
While many of the best combinations at cone 6 come from three or more glazes (which helps build depth and variation), I discovered several really striking two-glaze combinations. These combinations look great as they are, but also served as the basis
for the next set of more complex tests.
Three or More Glaze Combinations
For the three or more glaze combination tests, I dipped the entire tile in the first glaze for two seconds, let it dry, then inverted the piece and dipped a second glaze for one second. The pieces were then given several hours to dry under a fan, at which
point a third glaze was applied by inverting the pieces and glazing the top 1/4 of the tile for one second. Finally, for certain combinations, a fourth glaze was applied at the very lip of the pot by inverting the piece and dipping it in glaze for
one second.
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18,515 Layers
Layering glazes is a passion! If you engage in careful glaze preparation, skillful application, and detailed note taking, you can create a nearly infinite variety of combinations. If you stocked only five glazes, you could layer them in 18,515 different ways! It should be noted, however, that color combinations do not work according to the traditional color wheel (e.g., red plus blue does not necessarily make purple). Additionally, the combinations of ingredients in the different glazes may intermingle in interesting ways. For example, a combination of two matte glazes can run down the side of a pot. For this reason, always use a cookie and/or wadding underneath any new (or known runny) combinations to minimize the need for grinding and potential damage to kiln shelves.
When layering glazes, first apply a base coat through dipping, pouring, brushing, or spraying. Allow it to dry to the touch before adding a second layer. The second and subsequent layers of glaze should be applied slightly thinner, either by using a shorter count or by decreasing the specific gravity. I have found that it’s best to wait 2 to 3 hours before applying a third or fourth coat—sometimes even overnight. To play it safe on new combinations, aim for the second glaze to go no lower than a third of the way down the pot and for the third coat to go no more than a quarter of the way down the pot. Once the degree of melt can be observed, you can adjust for the next firing.
When working with layering glazes, you may find that some glazes layer poorly, flaking off the glaze below it. A possible cause is a difference in clay content in the glazes. When a glaze with a high clay content is applied over a glaze with a lower one, the glaze with more clay can tend to flake off when it shrinks. Reversing the order of application can solve the problem, but it will give a different look to the layering. Alternatively, you can try adding 1% CMC gum or 2% bentonite clay to the low-clay content glaze. A glaze that has sat unused for some time and had a chance to flocculate may also tend to flake. If so, you could add one drop of the deflocculant Darvan 811 per cup and mix until the glaze noticeably thins.
Refiring at Cone 6
If a particular glaze emerges out of the kiln and displeases you, don’t be afraid to refire! This can take several forms at cone 6: previously salt-glazed, wood-fired, and high-fired work may be refired in oxidation to cone 6 either as-is or with the addition of more glaze. Pieces may be fired multiple times to cone 6, or they can be fired to a lower temperature with the addition of lusters, decals, china paints, or other low-fire applications. The first glaze firing should be seen as just that and doesn’t necessarily represent the end of the road. If you loved your piece before glazing but the glaze results make you want to chuck it in the dumpster or worse, it might be worth a refire.
Note that refiring will increase the amount of cristobalite in the clay body, and refired pieces can be more prone to dunting. Fire slowly, as refiring a glazed piece can cause it to explode in a glaze firing. I have only seen this once or twice, but the shards stuck to the other pots in the kiln and the kiln shelf. However, the ability to save, rectify, or even improve the look of a sad pot can be worth the risk, and I must say, it’s immensely satisfying when you turn a badly glazed piece around. My experience has been that refiring is generally a 50/50 proposition. Half of the time, the pot will look worse, but there are plenty of times when a refire will make you jump for joy.
Two-Glaze Combinations
Here’s where the fun begins! To get your bearings with any new set of glazes, you first want to test each glaze in combination with every other recipe in the set. For each glaze, I dipped ten of the tiles for a two-second count in the same glaze. I then inverted the piece and dipped the top one-quarter of the tile in a different glaze. With eleven base glazes, I ran a total of 110 two-glaze combination tests to see how each glaze operated with every other glaze in the group.
The results of the two-glaze combinations tests were, as one should expect, not all spectacular. In fact, some of the tests were downright ugly by anyone’s standards! But this is important information. Knowing which combinations do not reflect your aesthetic vision can be as important to honing your palette as knowing which ones represent you well.
In any case, these two-glaze combination tests will show you how the glazes perform with each other, including degree of runniness in each combination. You can use this information to make decisions about how much of the first glaze you want to show on the outside of your pot. If a combination doesn’t move that much, you now know that you can dip the second glaze further down the piece to create a different look. Similarly, for the very runny combinations, you now know that you should keep the second glaze toward the top of your pot to allow it to run.
While many of the best combinations at cone 6 come from three or more glazes (which helps build depth and variation), I discovered several really striking two-glaze combinations. These combinations look great as they are, but also served as the basis for the next set of more complex tests.
Three or More Glaze Combinations
For the three or more glaze combination tests, I dipped the entire tile in the first glaze for two seconds, let it dry, then inverted the piece and dipped a second glaze for one second. The pieces were then given several hours to dry under a fan, at which point a third glaze was applied by inverting the pieces and glazing the top 1/4 of the tile for one second. Finally, for certain combinations, a fourth glaze was applied at the very lip of the pot by inverting the piece and dipping it in glaze for one second.
the author Excerpted from Odyssey ClayWorks Director Gabriel Kline’s Amazing Glaze Recipes and Combinations, published by Quarto Press and available at www.quarto.com/books/9781589239807/amazing-glaze-recipes-and-combinations.
Unfamiliar with any terms in this article? Browse our glossary of pottery terms!
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