Where Do I Start?

Section: Glazes, Subsection: Introduction

Description

The perfect universal glaze recipe does not exist, the only way you will get the glazes you really need is formulate or adapt them yourself. Start with base recipes, learn to understand them from a material level, then learn the mechanisms, and chemistry.

Article

Probably you are reading this because you are not a chemist. Nevertheless you likely realize that there is a direct relationship between glaze chemistry and fired glaze properties like gloss, color, thermal expansion, hardness, melting temperature, etc. That means you will never really understand glazes without knowing something about the chemistry.

What exactly do we mean by "glaze chemistry"? It means simply that you view your glazes as made of oxides like SiO2, Al2O3, Na2O, etc and you rationalize their fired behavior in terms of oxide makeup. A compilation of the oxide makeup of a glaze is called a "formula". There are about 10 oxides you need to learn about, all of your raw materials are composed of them. Glaze calculation software automates the conversion from recipe to formula.

Likely you may be overestimating the difficulty of learning glaze chemistry but we urge you to give this a chance. Twenty hours of learning the oxide viewpoint will empower you to adjust and formulate your own glazes and could save you many years of struggle on the glaze recipe treadmill.

Consider where you are coming from:

If you have been a "glaze gambler" spinning the roulette wheel of recipes in pursuit of that perfect recipe that never comes then to fully benefit from the chemistry approach you are going to have to break this habit to some extent, have faith that a methodical "understand it" approach will be better.
If you are constantly "fighting a glaze war" trying to get some control and find that glazes that look good are temperamental to use and fire or they leach, scratch, craze, run, bubble, crystallize or fire off color or gloss. To take control you will have to learn what it is about the chemistry that contributes to these problems and how to juggle oxides to move in a direction that improves things.
If you want to learn and understand basic glaze mechanisms so you can formulate and adjust your own recipes then start with our base recipes for low, medium and high temperature and read the articles on how they were formulated and adjusted (click the articles link above to find them). Read trouble shooting articles to learn the relationship between chemistry and common glaze problems.
Your company or school has a few glaze recipes that are treated as if they were "dropped from heaven" but you would like to improve them. Study the relationship between the properties you want to impact and chemistry (pay special attention to the possible side effects of any changes to make). Also learn about how to think on the material and physical properties levels to balances any theories you formulate.
If you teach a class first learn to teach your students to understand materials and the physical properties they bring to the glaze slurry. Then introduce the concept of chemistry as a determinant of fired glaze properties and help them to also view materials as "sources of oxides".
If consultants or supplier reps visit your company and mess about with your glazes but never stay long enough to really understand them then learn the chemistry yourself.
If you learned ceramic chemistry in university and have lost it over time because you function in an industrial environment that relies totally on supplier promoted "material level" thinking you likely face an uphill battle with company or department management on the wisdom of taking the lower level chemistry approach to controlling the glazes. Wait for a crisis having a chemistry-related solution that is being mismanaged by narrow material-level thinking. Use the articles link above and go to the Trouble Shooting section under glazes.
If your company or organization has far too many different glaze recipes and stocks way too many materials learn to view materials as oxide suppliers and study what each oxide does. Review the lessons in the INSIGHT manual about how to substitute different materials yet supply the same oxides. Read about base glazes and how to identify mechanisms so you can adopt a base-glaze-with-adjustments approach.
If you use commercial glazes and either cannot justify the expense anymore or cannot solve problems for lack of content information, then learn about base glazes and develop or adjust one to fit your body. Then experiment with stain and opacifier additions and study chemistry issues surrounding colors that do not develop as expected.

Places to start

The best place to learn is to begin working through the lessons in the INSIGHT software manual (you can also watch videos on each INSIGHT lesson in the Learning Center at Digitalfire.com). These lessons teach all sorts of problem solving, formulation and adjustment techniques.
The best place for on-line reference information is right here: use the articles, oxides, materials and glossary links above.
Remember, use the links above to find what you need.
If you are new to the concept of glaze chemistry we encourage you to start with an article on one of our base glazes and learn why each material is there. Then learn to appreciate the value of having a base glaze that is adjustable, has the right gloss and melting temperature, has good application properties, fits your clay body, etc.
Learn to recognize the mechanisms of glazes, that is, what materials or oxides make them different from a transparent base. Then transplant these mechanisms into your own base glazes that you have adapted or formulated.
Learn to recognize what a typical glaze formula for your glaze type "looks like". Develop a sense for which oxides can be traded for others and the possible side effects of such trades.
Visit our Glaze Dragon and Formulate Your Own Glazes pages to "tune in" to our philosophy and the critical need for a change in the way ceramics is taught and done.
Download our INSIGHT software and its instruction manual at http://digitalfire.com and try it for free (if you are not sure how to download and install software from the net, there are links on the download page to learn).
If you are unsure just try the INSIGHT approach, install it and start on page 1 of the manual. If you have problems email us and we will guide you through things, even if it takes weeks. If you take it one step at a time you will never regret this whole new way of approaching the ceramic process.

If you are going to make ceramic ware, put good glazes on it. Remember, a "good" glaze is a lot more than one that just has a pleasing fired appearance. There is no one-glaze-that-works-for-everyone. We cater to people that want to start out right, or have been kicked around long enough that they are ready to learn why, they want to "understand". You will never likely get the glaze you really want until you formulate or adapt them yourself.

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Authors

Tony Hansen (Owner)

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