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Glaze Chemistry

Remember, in high school chemistry class when you found yourself thinking, “when will I ever use this stuff in my life?” (unless, of course, you always dreamed of becoming a chemist). Well, once you have become hooked on pottery and ceramics, you will probably find yourself delving into glaze chemistry. Learning how different materials contribute to glazes and clay bodies is very important in expanding your abilities as a ceramic artist. So here we’ve gathered a bunch of articles and information on glaze chemistry to help you understand this incredibly complex and fascinating subject. 33 Tried and True Glaze Recipes, a perfect resource for potters and ceramic artists who are ready to experiment with custom glazes, or for those who have grown tired of their own tried and true glazes.


Hirsh Satin Matt Base Glaze, Bowls by Joseph Pintz.

What Makes a Matte Glaze Matte? A Helpful Explanation of the Chemistry Behind Matte Glazes

Posted On October 18, 2010 18 Comments

I looooooooooooove a matte glaze, but I have to admit, other than some very basic information, I didn’t really have a good understanding of what makes a glaze matte…that is, until I read a recent Technofile article in Ceramics Monthly. What’s Technofile, you ask? It is a terrific new department in CM in which a technical issue in ceramics is explained in depth by an expert. Today, as a sampling of the great stuff in Technofile, I am presenting an excerpt on matte glazes (on account of my deep affection for these surfaces!).

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The New World of Crystalline Glazes: Developing Beautiful Crystals in Reduction

Posted On October 6, 2010 21 Comments

In today’s post, crystalline potter Diane Creber explains the basics of growing crystals and how crystalline glaze potters have been recently experimenting using reduction to enhance the pre-formed crystals in their glazes. Plus she shares a couple of great crystalline glaze recipes and a crystalline firing program for a digital controller.

Undulating Rim Platter, 16 inches in diameter, wheelthrown and altered white stoneware, with Blue-Green/Copper Red Glaze sprayed over scrap glaze, fired to Cone 6 in reduction.

Five Reasons to Convert Cone 10 Reduction Glazes to Cone 6: A Potter Shares His Rationale and His Recipes

Posted On September 22, 2010 34 Comments

Today, Rick Malmgren explains the benefits of firing his reduction glazes lower and shares some of his great cone 6 reduction glaze recipes.

Technofile: Glaze Fit

Posted On May 5, 2010 2 Comments

Though many are unaware of it, poor glaze fit can reduce the strength of a fired ceramic piece to as little as one-fifth the strength of a similar piece with ideal glaze fit. While good glaze fit seldom occurs by accident, it can be planned for and controlled. Some ceramic artists use glaze fit to induce crazing as a decorative technique (crackling) while others artists may want to avoid a “crackle” glaze.

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Glaze Chemistry 101: A Quick Course on How To Make and Test Your Own Custom Ceramic Glazes

Posted On February 8, 2010 27 Comments

In today’s post, we are presenting a little intro to glaze mixing and testing from Richard Zakin. In it he explains how the glaze making process is easily mastered if you have the right tools, follow an ordered procedure, and take the work seriously.

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How Glazes Melt: In Search of the Elusive Eutectic

Posted On December 9, 2009 2 Comments

Phases are specific forms of materials. The most familiar phases are solid, liquid and vapor. Any phase of a material is identical in composition and structure in all parts of that phase. For instance, a glass of water is the liquid phase of H2O, top to bottom; if it weren’t, we’d call it something else, like ice if it were solid (structural change), or lemonade if it had lemon and sugar dissolved in it (compositional change).

Latex resist was painted on the lip and underside of this porcelain vessel and 10% potassium dichromate was painted on the entire bowl. The latex was then removed and the following WSMS solutions were dotted and brushed on: 15% cobalt chloride, 50% cobalt chloride, 25% iron chloride, 50% nickel chloride and an "all gray" solution (10 grams each of potassium permangantate, cobalt chloride, molybdic acid and iron chloride in 100cc water).

Salts of the Earth

Posted On November 17, 2009 9 Comments

Beautiful, soft, muted-color brushstrokes and washes of water-soluble metal salts decorate Gary Holt’s translucent porcelain bowls and plates. The simplicity and quiet presence of his works belie the years that Holt spent experimenting and perfecting his technique. Using water-soluble metals salts (WSMS) demands excellent technical skills and careful attention to details.

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Leaving Bariumville: Replacing Barium Carbonate in Cone 10 Glazes

Posted On November 17, 2009 5 Comments

Barium carbonate has long been used as an ingredient in high-fire glazes, sometimes conferring unique properties upon glazes. One of the alkaline earth carbonates, it has also been used as rat poison (large doses can be toxic to humans as well). Glazes containing it ought to be checked for barium leaching if they are intended to hold food or drink, or reserved for surfaces that do not come into contact with food. It is not my intent to present the research on barium toxicity here, but to present a course of action for replacing it in glazes.

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The Many Faces of Iron: An Exploration in Cooling

Posted On November 16, 2009 4 Comments

One of the more fascinating, sometimes frustrating parts of ceramics is learning to balance the innumerable factors that affect the outcome of a firing. Glaze ingredients, the clay body used, firing cycles, atmospheres, kiln-stacking techniques and geography (to name a few variables) can all affect firing results.

gloss-blue-glaze by Jeff Zamek

Glazes: Materials, Mixing, Testing, Firing

Posted On November 5, 2009 4 Comments

How many times have you copied a glaze formula, only to find that it didn’t work as expected? It is not unheard of for glazes with the same formula to produce different results. While this may seem like a dead end, it does not have to be.