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Where do I start in understanding glazes?

Description

Break your addiction to online recipes that don't work or bottled expensive glazes. Learn why glazes fire as they do. Why each material is used. How to create perfect dipping and drying properties. Even some chemistry.

Article

Likely you have already watched lots of Youtube videos and found there are many ways to approach ceramics. Hobbyists and artists often think of clay as a "canvas" and glazes as "paints", they imagine showcasing their painting skills with artistic designs, they enter with an expectation of few issues and creating the exact colors and surfaces they want (from the expensive bottled glazes they assume won't craze or shiver on their bodies). Others enter with the desire to mix their own clays, formulate their own glazes, build their own kilns and they relish the new things learned with each firing. These often embark on mixing recipes found on Pinterest, Glazy or Facebook, hoping they will somehow magically work.

In industry the prevailing culture is more and more toward dependence on suppliers, getting by with the least knowledge possible. We are often amazed at how little knowledge technicians working in huge factories sometimes have!

You may have realized by now that this site is dedicated to fighting these cultures (which we personify as "the glaze dragon"). Understanding glazes better can empower you in many ways.

• Understand the difference between a base-coat dipping glaze, a dipping glaze and a brushing glaze.
• Find good glossy, matte and fluid glossy base recipes in your temperature range. Work with these and adjust them to fit your clay. Substitute your materials and fix other issues (e.g. poor suspension or application properties, crazing or shivering, excessive drying shrinkage, micro-bubbling, crystallization). Use them pure (or with added zircon to whiten and make them opaque) as liner glazes. Then add colorants and variegators for decorative surfaces. Examples of bases we developed this way are G2934Y, G2926B and G3806C (links below or findable on google).
• Be slow to bring a new recipe into your operation unless you understand it. Could you add its mechanism (colorants, opacifiers and variegators) to a base recipe you already have?
• Learn more about the materials you are using. Are they there to make the glaze melt? To color it? To suspend it in the bucket? To variegate the color or opacify the glass? To make it crystallize on firing? To matte it? Have they been well chosen to source the chemistry needed? Etc.
• Learn about how to make a slurry suspend well in the bucket (by controlling its specific gravity and thixotropy). This is super important, the vast majority of potters do not know how to do it. The rheological properties (specific gravity, viscosity, thixotropy) of almost any glaze slurry can be fine-tuned so that it will go on evenly without drips and dry quickly and to the right thickness on dense or porous bisque ware.
• Practice spotting the 'mechanisms' in recipes. What materials in the recipe make them fire the way they do? When you see recipes, mentally disassemble them into their base, additions and mechanisms.
• Although you are not a chemist you likely realize that fired glaze properties like gloss, color, thermal expansion, hardness, melting temperature, etc. are most directly related to 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 your materials as suppliers of them. The oxide makeup of a glaze is called a "formula". There are about 10 oxides to learn about, your raw materials contribute them. Using glaze chemistry (e.g. an account at insight-live.com) you can calculate the formula of a recipe.
• Learn to be demanding. Do no accept naked (undocumented) recipes. Do not accept problems like crazing, scratching, leaching, micro-bubble clouding, settling in the bucket. Learn to fix them. Don't work with temperamental glazes (e.g. rutile blues, high Gerstley Borate jellies) unless you understand the reason to tolerate them. Do not accept high reject rates.
• Do not waste time, be willing to work. Do lots of testing. Most of your tests should be smaller changes to recipes you have so you can learn something. Do not be afraid of failure, it teaches us.
• Document. Document your failures. With good pictures. Use an account at insight-live.com to record every recipe you make, every test firing, every project. You will find the ability to see recipes side-by-side with pictures, data, notes and chemistry invaluable in determining what changes to make next. Your account will also immerse you in reference material so you will be learning constantly.
• Watch my timeline at digitalfire.com and plainsmanclays.com. If you are signed up at insight-live.com you will get a monthly technical tip email from me every month.

Are you concerned about producing safe, non-leaching glazes?

It is about balance in the chemistry, not saturating it with heavy metals, about firing in the way appropriate for the recipe, about liner glazing. About knowing how to adjust. It’s not rocket science. It’s about not trusting anything with significant percentages of colorants (or things like barium carbonate, lithium carbonate), even commercial glazes, without doing simple leach testing. Just get started taking the new approaches mentioned here and you will become opinionated about leaching in no time!

Are you at a school, art center or club?

• Does your school have a few recipes that are treated as if they were "dropped from heaven"? There is plenty of information here to help you improve them. Learn how to determine if you need to approach the problem on one or more of the material, process or chemistry levels. It is also likely there are some are leaching metals. And very likely crazing.
• There is a good chance that every single bucket of glaze is improperly mixed (so it does not suspend well, does not go on evenly or dry quickly without cracks). Read the article on Thixotropy (link below). If you can turn those rock-hard-on-the-bottom buckets into the most silky and easy-to-use glaze they have ever seen you will be a hero!
• 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, how the materials source it to the glaze recipe and how it is the most important a determinant of fired glaze properties. Then teach them about rheology and how to identify a mechanism.
• Learn to make your own jars of paintable glazes. These are gummed and desirable in many situations (and much less expensive for bright colors).

Are you at a factory?

• Do consultants or supplier reps visit your company and mess about with your glazes but never stay long enough to explain anything or to really understand your issues? Learn the chemistry and physics yourself and take control. Study the contribution of each glaze material. Don't use frits that suppliers will not provide chemistry data for.
• Wait for a crisis with a glaze, the solution to which is being mismanaged by narrow material-level or supplier-dependent thinking. Solve it using chemistry. Or thorough and documented testing (use the Trouble-Shooting section here for ideas).
• Does your company or organization have far too many different glaze recipes and stock too many materials? Learn to view materials as oxide suppliers. Study what each oxide does. Review the info here on 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-with-variations approach. In the end the company will have fewer recipes to manage.
• 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

• https://digitalfire.com: The information in the articles, oxides, materials and glossary sections here.
• If you are new to the concept of glaze chemistry start with an article on one of our base glaze recipes 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.
• Get an account at https://insight-live.com and start entering the recipes you know and use already. Learn how to make it show the chemistry and compare them side-by-side. Document everything you know and learn about them. With pictures.

If you are going to make ceramic ware, put good glazes on it. Remember, a 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 glazes you really want until you formulate or adapt them yourself.

Related Information

Better to mix your own cover glazes for production?

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Yes. In this case the entire outside and inside of the mug need an evenly applied coat of glaze. In production, it would not make sense to attempt this by painting. For these reasons: Cost, quality, convenience. The right pail has 2 gallons of G2934Y base with 10% Cerdec yellow stain: $135. Cost of jars with the same amount: Almost $300! And you have to paint them on in three coats with drying in between. The one in the pail is a true dipping glaze (unlike dipping glazes sold by glaze manufacturers that dry slowly and drip-drip-drip just like brushing ones). This one dries immediately after dipping in a perfectly even layer (if mixed according to our instructions). And a bonus: This pail can be converted to brushing or base-layering versions using CMC gum.

Dip-glazing vs. brush-on glazing: Which gives the more even surface?

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This is a clear glaze (G2931K) with 10% purple stain (Mason 6385). The mugs are cone 03 porcelain (Zero3). The mug on the left was dipped (at the bisque stage) into a slurry of the glaze (having an appropriate specific gravity and thixotropy). The glaze dried in seconds. The one on the right was painted on (two layers). Like any paint-on glaze, it contains gum (1% CMC). Each layer required several minutes of application time and fifteen minutes of drying time. Yet it is still not evenly applied.

Brush-on commercial pottery glazes are perfect? Not quite!

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Paint-on glazes are great sometimes. But they are even greater if you know the recipe, then you can make more and make a dipping version for all the times when that is the better way to apply. Why is that better? Because you have a huge advantage over a glaze manufacturer: You already have clear glossy and matte base recipes that fit and work on your clay body. You can add the stains and opacifiers to these (with gums to make them paintable) and make your own jars. Don't have base recipes??? Let's get started developing them with an account at insight-live.com (and the know-how you will find there)!

Think the idea of mixing your own glazes is dead? Nope!

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These are two pallets (of three) that went on a semi-trailer load to a Plainsman Clays store in Edmonton this week. They are packed with hundreds of bags of powders used to mix glazes. More and more orders for raw ceramic materials are coming in all the time. Maybe you are using lots of bottled glazes but for a cover or a liner glaze it is better to mix your own. And cheaper! And there are lots of recipes and premixed powders here to do it. One of the big advantages is that when you dip ware into a properly mixed slurry it goes on perfectly even, does not run and dries on the bisque in seconds. No bottled glaze can do that.

VC71 is crazing. How can this be fixed?

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These cone 6 porcelain mugs have glossy liner glazes and matte outers: VC71 (left) crazes, G2934 does not (it is highlighted using a felt marker and solvent). Crazing, while appropriate on non-functional ware, is unsanitary and severely weakens the ware (up to 300%). If your ware develops this your customers will bring it back for replacement. What will you do? The thermal expansion of VC71 is alot higher. It is a product of the chemistry (in this case, high sodium and low alumina). No change in firing will fix this, the body and glaze are not expansion compatible. Period. The fix: Change bodies and start all over. Use another glaze. Or, adjust this recipe to reduce its thermal expansion.

What can you do using glaze chemistry? More than you think!

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There is a direct relationship between the way ceramic glazes fire and their chemistry. These green panels in my Insight-live account compare two glaze recipes: A glossy and matte. Grasping their simple chemistry mechanisms is a first step to getting control of your glazes. To fixing problems like crazing, blistering, pinholing, settling, gelling, clouding, leaching, crawling, marking, scratching, powdering. To substituting frits or incorporating available, better or cheaper materials while maintaining the same chemistry. To adjusting melting temperature, gloss, surface character, color. And identifying weaknesses in glazes to avoid problems. And to creating and optimizing base glazes to work with difficult colors or stains and for special effects dependent on opacification, crystallization or variegation. And even to creating glazes from scratch and using your own native materials in the highest possible percentage.

Comparing two glazes having different mechanisms for their matteness

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These are two cone 6 matte glazes (shown side by side in an account at Insight-live). G1214Z is high calcium and a high silica:alumina ratio. It crystallizes during cooling to make the matte effect and the degree of matteness is adjustable by trimming the silica content (but notice how much it runs). The G2928C has high MgO and it produces the classic silky matte by micro-wrinkling the surface, its matteness is adjustable by trimming the calcined kaolin. CaO is a standard oxide that is in almost all glazes, 0.4 is not high for it. But you would never normally see more than 0.3 of MgO in a cone 6 glaze (if you do it will likely be unstable). The G2928C also has 5% tin, if that was not there it would be darker than the other one because Ravenscrag Slip has a little iron. This was made by recalculating the Moore's Matte recipe to use as much Ravenscrag Slip as possible yet keep the overall chemistry the same. This glaze actually has texture like a dolomite matte at cone 10R, it is great. And it has wonderful application properties. And it does not craze, on Plainsman M370 (it even survived a 300F-to-ice water IWCT test). This looks like it could be a great liner glaze.

Common dipping glazes converted to jars of high SG brushing

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These are cone 6 Alberta Slip recipes that have been brushed onto the outsides of these mugs (three coats gave very thick coverage). Recipes are GA6-C Rutile Blue on the outside of the left mug, GA6-F Alberta Slip Oatmeal on the outside of the center mug and GA6-F Oatmeal over G2926B black on the outside of the right mug). These are examples of high specific gravity brushing glazes. One-pint jars are made using 500g of glaze powder, 280g of water and 75g of Laguna CMC gum solution (equivalent to 1%). Because no Veegum is being used this blender mixes to a slurry of super high 1.6 specific gravity (SG). Commercial glazes have a much lower specific gravity (thus much more water), giving better paintability and gelling but requiring more coats. Still, this approach is good for Alberta Slip because it is highly plastic and comprises the bulk of the recipe. The gum removes the need to roast 50% of it and the plasticity of the Alberta Slip helps suspend the slurry.

Commercial glazes on decorative surfaces, your own on food surfaces

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These cone 6 porcelain mugs are hybrid. Three coats of a commercial glaze painted on outside (Amaco PC-30) and my own liner glaze, G2926B, poured in and out on the inside. When commercial glazes (made by one company) fit a stoneware or porcelain (made by another company), it is often purely an accident! So test thoroughly or just use them on the outsides. For inside food surfaces make or mix a liner glaze already proven to fit your clay body, you have to option to make it as a dipping glaze or brushing glaze. One that is sensible enough to fit common sense recipe limits and not have an unbalanced chemistry. And you can use quality materials that you know deliver no toxic compounds to the glass and that are proptioned to deliver a balanced chemistry.

Imagine if you had everything for production at home during Covid-19

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This is what you need to be independent, to create your own manufacturing company in your garage. Some of the prices are "instead of" rather than additive. There are many approaches to glazes, the more you are willing to learn the better you will be able to make your own (and save a lot). We recommend the cone 6 range using a small test kiln (like this 220v ConeArt GX119, don't scrimp on this, go for quality and the practicality of a Genesis controller). A kiln you can fire often and inexpensively is a key enabler to learning, developing techniques, products, designs, durable and decorative surfaces, solving problems. It can be fired multiple times a day. And it is big enough for mugs and similar sizes. It will get you into the habit of using some of your creativity for experimenting. It will give you the successes early on that will inspire you to press on learning. When you are ready, then get a big kiln and hit-the-ground-running. This potter's wheel is the best available and will last a lifetime, these often appreciate in value over time. And, build yourself a good plaster table. You will use it constantly. Not shown here is a propeller mixer, also an important tool. And you will need a sink equipped with a sink trap (Gleco Trap).

Tried and True recipes. Really?

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Books and web pages with flashy pictures are the centrepiece of an addiction-ecosystem to recipes that often just don't work. Maybe these are "tried" by a lot of people. But are they "true"? Most are so-called "reactive glazes", outside normal practice - to produce visual interest they run, variegate, crystallize, pool, break, tint, go metallic, etc. But this happens at a cost. And inside special procedures and firing schedules that need explaining. It is not obvious these are understood by the recipe authors or sharers. And these recipes are dated and contain troublesome and unavailable materials. We use frits now to source boron. Stains are superior to raw colorants, even in glazes like this. Many of these will craze badly. And many will not suspend in the bucket. And will run during firing. Reactive glazes have other common issues: Blistering, leaching, cutlery marking, fuming. Trying colors in differing amounts in different base recipes is a good idea. But the project is most beneficial when it shows color response in terms of quality recipes of contrasting chemistries. The point of all of this: Understand a few glazes and develop them, rather than throwing spaghetti against the wall hoping something sticks. Commercial reactive glazes are an alternative also.

Global supply chain issues? Learn to mix and adjust your own bodies, glazes

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Material prices are sky rocketing. And, the more complex your supplier's supply chain the more likely they won't be able to deliver. How can you adapt to coming disruption, even turn it into a benefit? Learn to create base recipes for your glazes and even clay bodies. Learn now how to substitute frits and other materials in glazes (get the chemistry of frits you use now so you are ready). Even better: Learn to see your glaze as an oxide formula. Then calculate formula-to-batch to use whatever materials you can get. Learn how to adjust glazes for thermal expansion, temperature, surface, color, etc. And your clay bodies? Develop an organized physical testing regimen now to accumulate data on their properties, learn to understand how each material in the recipe contributes to those properties. Armed with that data you will be able to adjust recipes to adapt to changing supplies.

Covid taught us about supply interruptions

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Material prices were sky rocketing (and still are). Prepared glaze manufacturers have complex international supply chains. Now might be the time to start learning how to weigh out the ingredients to make your own. Armed with good base glazes that fit your clay body (without crazing or shivering) you will be more resilient to supply issues. Add stains, opacifiers and variegators to the bases to make anything you want. That being said, ingredients in those recipes may become unavailable! That underscores a need to go to the next step and "understand" glaze ingredients. And even improve and adjust recipes. It is not rocket science, it is just work accompanied by organized record-keeping and good labeling.

Is the N505 cone 6 matte glaze recipe what you think it is?

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This recipe is from page 2 of the booklet: "15 Tried & True Cone 6 Glaze Recipes". Click the following code, G3955, to see more information on how we compare it with G2934 and another matte, G1214Z1. This flow test and these test tiles were in the same kiln, fired at cone 6 using our PLC6DS schedule. Obviously, the defining characteristic of N505 is its extreme melt fluidity, clearly it is not a native cone 6 glaze (it's a lower temperature one being used above its range). Still, the surface on the N505 tile is arguably more interesting, that's why it's popular with potters. But is it functional? Some felt pen marking helps reveal one big difference: The micro surface of the G2934 is much smoother. From the chemistry shown on Insight-Live side-by-side screenshot very low Al₂O₃ and SiO₂ are evident. This also reveals it should fire glossy, so it is a "crowbar matte", forced to be such by 6% addition of magnesium carbonate. I was understandably suspicious that this glaze would have more issues than it actually does. Although the surface is rough and it does mark and stain, it can be cleaned with effort. The low SiO₂ suggests it would cutlery mark but it does seem quite hard. However on the matter of leaching the jury is still out (a stain needs to be added for testing in an acid). Crazing is another possible issue. Our G3924 recipe, although more boring, excels on all four of these tests.

A settling, running, crazing pottery glaze gets a makeover

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The original cone 6 recipe, WCB, fires to a beautiful brilliant deep blue green (shown in column 2 of this Insight-live screen-shot). But it is crazing and settling badly in the bucket. The crazing is because of high KNaO (potassium and sodium from the high feldspar). The settling is because there is almost no clay. Adjustment 1 (column 3 in my Insight-live.com account) eliminates the feldspar and sources Al₂O₃ from kaolin and KNaO from Frit 3110. The chemistry of the new chemistry is very close. To make that happen the amounts of other materials had to be juggled (you can click on any material to see what oxides it contributes). But the fired test revealed that this one, although very similar, is melting more (because the frit releases its oxides more readily than feldspar). Adjustment 2 (column 4) proposes a 10-part silica addition (to supply more SiO₂). SiO₂ is the glass former, the more a glaze will accept without losing the intended visual character, the better. Silica is refractory so the glaze will run less. It will also fire more durable and be more resistant to leaching.

Cutlery marking here is directly related to the chemistry of the glaze

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This is an example of cutlery marking in a cone 10 silky matte glaze lacking Al₂O₃, SiO₂ and having too much MgO. Al₂O₃-deficient glazes often have high melt fluidity and run during firing, this freezes to a glass that lacks durability and hardness. But sufficient MgO levels can stabilize the melt and produce a glaze that appears stable but is not. Glazes need sufficient Al₂O₃ (and SiO₂) to develop hardness and durability. Only after viewing the chemistry of this glaze did the cause for the marking become evident. This is an excellent demonstration of how imbalance in chemistry has real consequences. It is certainly possible to make a dolomite matte high temperature glaze that will not do this (G2571A is an example, it has lower MgO and higher Al₂O₃ and produces the same pleasant matte surface).

Growing incredible crystals in a ceramic glaze is about the chemistry

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Closeup of a crystalline glaze. Crystals of this type can grow very large (centimeters) in size. These grow because the chemistry of the glaze and the firing have been tuned to encourage them. This involves melts that are highly fluid (lots of fluxes) with added metal oxides and a catalyst. The fluxes are dominated by K₂O and Na₂O (from frits) and the catalyst is zinc oxide (enough to contribute a lot of ZnO). Because Al₂O₃ stiffens glaze melts, preventing crystal growth, it can be almost zero in these glazes (clays and feldspars supply Al₂O₃, so these glazes have almost none). The firing cycles involve rapid descents, holds and slow cools (sometimes with rises between them). Each discontinuity in the cooling curve creates specific effects in the crystal growth. These kinds of glazes are within the reach of almost anyone today since electronic controller-equipped kilns are now commodity items and anyone can fiddle with the chemistry and manage the testing of glazes in their insight-live.com account.

These common Ferro frits have distinct uses in traditional ceramics

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I used Veegum to form 10 gram GBMF test balls and fired them at cone 08 (1700F). Frits melt really well, they do have an LOI like raw materials. These contain boron (B₂O₃), it is a low expansion super-melter that raw materials don’t have. Frit 3124 (glossy) and 3195 (silky matte) are balanced-chemistry bases (just add 10-15% kaolin for a cone 04 glaze, or more silica+kaolin to go higher). Consider Frit 3110 a man-made low-Al₂O₃ super feldspar. Its high-sodium makes it high thermal expansion. It works really well in bodies and is great to make glazes that craze. The high-MgO Frit 3249 (made for the abrasives industry) has a very-low expansion, it is great for fixing crazing glazes. Frit 3134 is similar to 3124 but without Al₂O₃. Use it where the glaze does not need more Al₂O₃ (e.g. already has enough clay). It is no accident that these are used by potters in North America, they complement each other well (equivalents are made around the world by others). The Gerstley Borate is a natural source of boron (with issues frits do not have).

In pursuit of a reactive cone 6 base that I can live with

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These GLFL tests and GBMF tests for melt-flow compare 6 unconventionally fluxed glazes with a traditional cone 6 moderately boron fluxed (+soda/calcia/magnesia) base (far left Plainsman G2926B). The objective is to achieve higher melt fluidity for a more brilliant surface and for more reactive response with colorant and variegator additions (with awareness of downsides of this). Classified by most active fluxes they are:
G3814 - Moderate zinc, no boron
G2938 - High-soda+lithia+strontium
G3808 - High boron+soda (Gerstley Borate based)
G3808A - 3808 chemistry sourced from frits
G3813 - Boron+zinc+lithia
G3806B - Soda+zinc+strontium+boron (mixed oxide effect)
This series of tests was done to choose a recipe, that while more fluid, will have a minimum of the problems associated with such (e.g. crazing, blistering, low run volatility, susceptibility to leaching). As a final step the recipe will be adjusted as needed. We eventually evolved the G3806B, after many iterations settled on G3806E or G3806F as best for now.

Commercial supposedly safe glazes leaching. I liner glaze is needed.

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Three cone 6 commercial bottled glazes have been layered. The mug was filled with lemon juice overnight. The white areas on the blue and rust areas on the brown have leached! Why? Glazes need high melt fluidity to produce reactive surfaces like this. While such are normally subject to leaching, supposedly the manufacturers were able to tune the chemistry of each to make them resistant. But the overlaps mingle well (because of the fluidity), they are new chemistries, less stable ones. What is leaching? Cobalt! Not good. What else? We do not know, these recipes are secret. It is better to make your own transparent or white liner glaze (either as a dipping glaze or brushing glaze). Not only can you pour-apply it and get very even coverage, but you know the recipe and have the control to adjust it to fit your clay body.

Links

Articles	G1214M Cone 5-7 20x5 glossy transparent glaze This is a base transparent glaze recipe developed for cone 6. It is known as the 20x5 or 20 by 5 recipe. It is a simple 5 material at 20% each mix and it makes a good home base from which to rationalize adjustments.
Articles	Working with children Go in with both eyes open if you are planning to work with clay with a group of children! A lot can go wrong but it can be unforgettable for them when it goes right.
Articles	G1916M Cone 06-04 transparent glaze This is a frit based boron glaze that is easily adjustable in thermal expansion, a good base for color and a starting point to go on to more specialized glazes.
Glossary	Brushing Glaze Hobbyists and increasing numbers of potters use commercial paint-on glazes. It's convenient, there are lots of visual effects. There are also issues compared to dipping glazes. You can also make your own.
Glossary	Rheology In ceramics, this term refers to the flow and gel properties of a glaze or body suspension (made from water and mineral powders, with possible additives, deflocculants, modifiers).
Glossary	Glaze Mixing In ceramics, glazes are developed and mixed as recipes of made-made and natural powdered materials. Many potters mix their own, you can to. There are many advantages.
Glossary	Reactive Glazes In ceramics, reactive glazes have variegated surfaces that are a product of more melt fluidity and the presence of opacifiers, crystallizers and phase changers.
Glossary	Mechanism Identifying the mechanism of a ceramic glaze recipe is the key to moving adjusting it, fixing it, reverse engineering it, even avoiding it!
Glossary	Limit Formula A way of establishing guideline for each oxide in the chemistry for different ceramic glaze types. Understanding the roles of each oxide and the limits of this approach are a key to effectively using these guidelines.
Glossary	Thixotropy Thixotropy is a property of ceramic slurries. Thixotropic suspensions flow when you want them to and then gel after sitting for a few moments. This phenomenon is helpful in getting even, drip free glaze coverage.
Glossary	Glaze Chemistry Glaze chemistry is the study of how the oxide chemistry of glazes relate to the way they fire. It accounts for color, surface, hardness, texture, melting temperature, thermal expansion, etc.
Glossary	Ceramic Oxide In glaze chemistry, the oxide is the basic unit of formulas and analyses. Knowledge of what materials supply an oxide and of how it affects the fired glass or glaze is a key to control.
Glossary	Decomposition In ceramic manufacture, knowing about the how and when materials decompose during firing is important in production troubleshooting and optimization
Glossary	Glaze Recipes Stop! Think! Do not get addicted to the trafficking in online glaze recipes. Learn to make your own or adjust/adapt/fix what you find online.
Recipes	G2931K - Low Fire Fritted Zero3 Transparent Glaze A cone 03-02 clear medium-expansio glaze developed from Worthington Clear.
Recipes	G2934 - Matte Glaze Base for Cone 6 A base MgO matte glaze recipe fires to a hard utilitarian surface and has very good working properties. Blend in the glossy if it is too matte.
Recipes	G2926B - Cone 6 Whiteware/Porcelain transparent glaze A base transparent glaze recipe created by Tony Hansen for Plainsman Clays, it fires high gloss and ultra clear with low melt mobility.
URLs	https://digitalfire.com/videos Tutorial Videos at Digitalfire
Projects	Recipes
Projects	Oxides

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