A Blog about Ceramic Art and Science
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Most Recent Blog Posts
Why Specific Gravity Isn’t Listed on Glaze Recipes
If you’ve been glazing for any length of time, you may have heard about the importance of measuring the specific gravity of your glazes and you may have found yourself wondering: “If it’s so important to measure specific gravity, why aren’t specific gravity values published on glaze recipes?”
How the Water in Your Glaze is Affecting Your Results
Does any of this sound familiar? You unload a piece from the kiln and the glaze turned out perfectly! So you glaze more pieces with the same glaze combination, fire them, and they turn out completely different… OR… You mix a small test batch of a glaze and LOVE how it looks…
How to Make a Good Kiln Wash to Protect Your Kiln Shelves
Kiln wash is a material that you can paint onto your kiln shelves. It looks very similar to a glaze when being applied. It acts as a barrier to prevent unexpected glaze runs or drips from ruining your shelves. Kiln shelves are made of a hard material that is similar to…
A Clay Reclaim Process Using a Pugmill/Clay Mixer
If you run a community studio or your personal studio is high production, you probably have a lot of clay scraps to deal with. This article will describe the clay reclaim process we use at the very busy pottery studio where I worked as technician for 6 years.
A Low Tech System for Recycling Clay Scraps
As clay artists, we’re so lucky that we can reduce the amount of waste we produce by reclaiming or recycling our unfired clay. When we make something that cracks, warps or doesn’t look how we wanted it to, we can reclaim our clay, bringing it back to its original state so…
What to Keep Track of in Your Glaze Journal
How Magic Becomes Science. Have you ever unloaded a BEAUTIFUL piece from the kiln and thought, “Gee, I wish I could remember how I did that”? A big part of glaze testing and advancing your understanding of glazes is record keeping. Whether you’re dipping test tiles or…
How to Turn a Matte Glaze Glossy with One Ingredient
Do you have a matte glaze that you wish was a bit glossier, or would you like a glossy version of one of your matte glazes? It’s really easy to convert a matte glaze to a glossy glaze, just by adding one ingredient…
How to Convert Kaolin to Calcined Kaolin
If you have too much clay in a glaze recipe, you might have issues with your glaze crawling during the firing. Crawling is where the glaze pulls away from the clay body due to a combination of shrinkage, poor adhesion and high surface tension.
How to Make a Saturated Epsom Salt Solution to Flocculate your Glazes
Flocculate… What Does That Even Mean? You may have heard this term “flocculate” in reference to glazes and thought it was a funny word but you’ve never really known what it means. Or you may have been told what it means several times and still…
How to Fix a Hard-Panned Glaze with Epsom Salts
Have you ever had a glaze settle into a rock hard layer on the bottom of your glaze bucket? It’s impossible to mix and even if you do get it mixed, it just settles out again. This annoying phenomenon is called “hard-panning” and it often happens to glazes that don’t have enough…
5 Reasons Why Your Large Batch of Glaze Doesn’t Match Your Test Batch
Has this ever happened to you? You mix up a test batch of a new glaze, dip a test tile and you like the result, so you mix up a large bucket, dip a test tile and your results look nothing like your test batch?
Start Mixing Your Own Ceramic Glazes – A Shopping List
Are you ready to start mixing your own glazes? Perhaps you’ve reached the point in your ceramics journey that you want to start understanding the materials you’re working with and what is actually happening when you put your pottery into the kiln.
Glaze Testing
What to Keep Track of in Your Glaze Journal
How Magic Becomes Science. Have you ever unloaded a BEAUTIFUL piece from the kiln and thought, “Gee, I wish I could remember how I did that”? A big part of glaze testing and advancing your understanding of glazes is record keeping. Whether you’re dipping test tiles or…
How to Turn a Matte Glaze Glossy with One Ingredient
Do you have a matte glaze that you wish was a bit glossier, or would you like a glossy version of one of your matte glazes? It’s really easy to convert a matte glaze to a glossy glaze, just by adding one ingredient…
15 Tips to Get Started with Glaze Testing
I find ceramic glazes to be absolutely fascinating. I had no idea when I started working with clay that glazes would become the main focus of my life. Glazing was always an afterthought and I basically ruined most of my pieces by glazing them…
Different Styles of Test Tiles You Can Make for Glaze Testing
The word “test tile” can refer to any shape of clay that’s used to test glazes, slips, underglazes, engobes etc. Test tiles can be any shape you wish and can be made in a variety of ways. In this post, I’ll share lots of different examples of ways you can…
99 Cone 6 Glazes You Can Try
Have you been looking for new glazes to add to your glaze palette? If so, I have 99 different cone 6 glazes you can try. That probably sounds like a lot to look through, but it’s really just 9 base glaze recipes plus 10 colour variations each.
Troubleshooting Commercial Underglazes
Have you experienced issues with commercial underglazes? Participate in my underglaze research project and help me find solutions for underglaze firing defects.
Testing Pencil Crayons at Cone 6
Writing information on test tiles I do a lot of glaze testing, which requires me to write testing info on my small test tiles. When I first started out, I used red iron oxide mixed with water and a paintbrush. This is what my teacher used and it worked well enough,...
Exploring One Glossy Glaze with Many Colours
Create a palette of compatible glazes When you first start mixing your own glazes, it can be overwhelming to decide on which glaze recipes you’re going to use. There are so many! There are literally thousands. On Glazy.org right now, there are over 20,000 published...
Exploring Iron Reds and Fast Cooling Cycles
Randy’s Red - A classic glaze recipe “Randy’s Red” is a recipe that has been around for a long time. I’m not even sure who the original “Randy” is. This glaze was one of the staple studio glazes at Cedar Hill Rec Centre where I worked as a studio technician for 6...
Understanding Cone 6 – NCECA presentation 2018
On Mar 15, 2018 I gave my first ever NCECA talk. I was part of a panel discussion called Glazes Without Borders, moderated by Matt Katz. My co-presenters Kiara Matos and Peter Berg gave talks about "Copper as a Flux" and "Copper Leaching and Glaze Durability". You can...
Studio Tips
How to Make a Good Kiln Wash to Protect Your Kiln Shelves
Kiln wash is a material that you can paint onto your kiln shelves. It looks very similar to a glaze when being applied. It acts as a barrier to prevent unexpected glaze runs or drips from ruining your shelves. Kiln shelves are made of a hard material that is similar to…
A Clay Reclaim Process Using a Pugmill/Clay Mixer
If you run a community studio or your personal studio is high production, you probably have a lot of clay scraps to deal with. This article will describe the clay reclaim process we use at the very busy pottery studio where I worked as technician for 6 years.
A Low Tech System for Recycling Clay Scraps
As clay artists, we’re so lucky that we can reduce the amount of waste we produce by reclaiming or recycling our unfired clay. When we make something that cracks, warps or doesn’t look how we wanted it to, we can reclaim our clay, bringing it back to its original state so…
How to Convert Kaolin to Calcined Kaolin
If you have too much clay in a glaze recipe, you might have issues with your glaze crawling during the firing. Crawling is where the glaze pulls away from the clay body due to a combination of shrinkage, poor adhesion and high surface tension.
Are You Mixing Your Glazes Well Enough?
Glaze results on the thin side? As a studio technician at a busy pottery studio, it’s my job to mix and maintain 20 different studio glazes. I’m also the one studio users often go to for help when their glazes don’t work out as they had hoped. Every now and then…
The Air Bubble Myth
There’s a common belief in ceramics that leaving pockets of air in your clay, either due to insufficient wedging or by creating an enclosed form, leads to explosions in the kiln. The belief is often communicated in these ways: “Poorly wedged clay containing air bubbles will explode…”
Temperature vs Heatwork – Why We Use Witness Cones
I receive a lot of glaze questions and the first question I generally ask in return is “What did the cones look like?” Knowing whether the kiln was over- or under-fired is important for diagnosing many glaze issues. Sometimes I’m told a kiln temperature in response. But…
How to Make a Cone Pack
In this post, you’ll learn how to make a cone pack using pyrometric witness cones set into a coil of clay. Cones are important for measuring the heatwork of your firings.
What’s the role of witness cones in a kiln-sitter kiln?
Question: Any suggestions for using witness cones when your kiln has a kiln-sitter rather than a controller? I have a small, old school doll kiln and can't create a schedule. All I can control is on, off, length of time. Put witness cones where you can see them during...
Specific Gravity
Why Specific Gravity Isn’t Listed on Glaze Recipes
If you’ve been glazing for any length of time, you may have heard about the importance of measuring the specific gravity of your glazes and you may have found yourself wondering: “If it’s so important to measure specific gravity, why aren’t specific gravity values published on glaze recipes?”
How the Water in Your Glaze is Affecting Your Results
Does any of this sound familiar? You unload a piece from the kiln and the glaze turned out perfectly! So you glaze more pieces with the same glaze combination, fire them, and they turn out completely different… OR… You mix a small test batch of a glaze and LOVE how it looks…
How to Make a Saturated Epsom Salt Solution to Flocculate your Glazes
Flocculate… What Does That Even Mean? You may have heard this term “flocculate” in reference to glazes and thought it was a funny word but you’ve never really known what it means. Or you may have been told what it means several times and still…
5 Reasons Why Your Large Batch of Glaze Doesn’t Match Your Test Batch
Has this ever happened to you? You mix up a test batch of a new glaze, dip a test tile and you like the result, so you mix up a large bucket, dip a test tile and your results look nothing like your test batch?
How to Measure the Specific Gravity of Your Glazes
In this video I demonstrate how to measure the specific gravity of a glaze I just mixed using a graduated cylinder and a scale. Measuring specific gravity is a way to calculate the water content of a glaze to ensure that each time you glaze, you have the same amount of water…
Why I Use a Graduated Cylinder for Measuring Specific Gravity
I use a graduated cylinder for measuring specific gravity. A slender container is going to have smaller increments than a wide container, giving higher accuracy. You could compare this concept to using a scale with 1g increments vs 5g increments. The smaller measurement is…
Why I Don’t Use a Hydrometer to Measure Specific Gravity
I didn’t always know about measuring specific gravity. Of the 10 years that I’ve been mixing glazes, I’ve only been measuring specific gravity for 3 of them. It wasn’t a technique I learned in school. But… I had heard about it enough times that eventually I used it to try…
Getting Clarity with Clear Glazes
There’s nothing worse than a cloudy clear glaze muddying up your beautiful slip design, screen printed images or coloured clay. How can we make sure our clear glaze is always clear and prevent it from going cloudy? In this article, I’ll explain some of the factors that affect the…
How to Measure Specific Gravity – Clay Week 2020
Here's a live demo of how to measure the specific gravity of your glazes so you can have more consistent results. Measuring specific gravity is a way to calculate and control the water content of your glazes. When the water content is consistent, application thickness...
Glazy.org Demos
What Glazes Can You Make with Limited Materials?
When you start looking for glaze recipes and have a limited number of materials on hand, you may find that you have almost (but not quite) all the materials for a million glaze recipes, but you can’t find a recipe that only uses the materials you currently have.
Glazy Demo – Adding Recipes and More
Do you use Glazy.org to store/share your glaze recipes? If you’re just hearing about Glazy for the first time, you should definitely go check it out. It’s a ceramics recipe website that allows you to store recipes with photos, share them with the community and analyze the chemistry/UMF of your glazes, all in one place.
Intro to Glazy.org – Video Tutorial
If you’ve never used Glazy.org before, this is a helpful tutorial to get started. In this tutorial, I go over the basics of using the site.
Adding Colourants in Glazy.org – Video Tutorial
In this tutorial, I go over how to add colourants to a recipe and keep the colourants separate from the base recipe so your base adds up to 100% and your colourants are shown as additions.
Material Substitutions with Glazy.org – Video Tutorial
In this tutorial, I show you how to use Glazy to make material substitutions using the UMF (Unity Molecular Formula).
Firing
How to Make a Good Kiln Wash to Protect Your Kiln Shelves
Kiln wash is a material that you can paint onto your kiln shelves. It looks very similar to a glaze when being applied. It acts as a barrier to prevent unexpected glaze runs or drips from ruining your shelves. Kiln shelves are made of a hard material that is similar to…
Temperature vs Heatwork – Why We Use Witness Cones
I receive a lot of glaze questions and the first question I generally ask in return is “What did the cones look like?” Knowing whether the kiln was over- or under-fired is important for diagnosing many glaze issues. Sometimes I’m told a kiln temperature in response. But…
What’s the role of witness cones in a kiln-sitter kiln?
Question: Any suggestions for using witness cones when your kiln has a kiln-sitter rather than a controller? I have a small, old school doll kiln and can't create a schedule. All I can control is on, off, length of time. Put witness cones where you can see them during...
What’s the difference between Orton self-supporting cones and large cones
Large cones vs Self Supporting cones Question: Orton temperature equivalents - I thought self supporting and large cones were interchangeable, but the table shows slightly different temps for the same rate. How critical are those differences? The Orton Cone Chart can...
Why does my kiln fire unevenly?
Why does my kiln fire unevenly? Question: “Why do I get different results on my cone pack based on which shelf-- top, middle, or bottom-- the pack is located?” Our kilns tend to fire unevenly and I've also had the same experience. The new Cone Art kiln that I bought...
Does a lower bisque temp = more pores?
How temperature affects the porosity of our bisque We start with bone dry greenware, which is porous. So all the water - the physical water - has evaporated from the clay body before the bisque firing. Then we put it into the bisque, where all of those particles...
How to Calibrate Your Kiln Sitter for Accurate Firings
If you’re anything like me, then your first kiln wasn’t or isn’t going to be the digital programmable kind. Many of us start out with a manual kiln that we got second hand. I have 4 different sized kilns in my home studio and none of them are digital or programmable.
Glaze Q&A Videos
When you flocculate a glaze with Epsom salts, how long does the effect last?
Question: When you use Epsom salts to flocculate a glaze, how long does that effect last? How often do you have to add more Epsom salts? Using Epsom salts to flocculate glazes Epsom salts are magnesium sulphate. When they're dissolved in water, the magnesium breaks...
How to achieve consistency with brushing glazes?
Question: “Brush on glazes are less consistent in my experience. How do we know the ideal consistency with a brush on glaze?”
Can you use bentonite instead of epsom salt for hard panning?
Question: Can you use bentonite instead of Epsom salt for hard panning? Dealing with hard-panning In my free Strategic Glazing class, I talk about flocculation. Flocculation is a way of increasing a glaze's viscosity without adjusting the specific gravity and without...
How to deal with glazing tong marks?
Question: When using tongs, what is a reliable method for covering the small holes left behind in a way that doesn’t show as a different color in the fired piece?
What’s the role of witness cones in a kiln-sitter kiln?
Question: Any suggestions for using witness cones when your kiln has a kiln-sitter rather than a controller? I have a small, old school doll kiln and can't create a schedule. All I can control is on, off, length of time. Put witness cones where you can see them during...
What’s the difference between Orton self-supporting cones and large cones
Large cones vs Self Supporting cones Question: Orton temperature equivalents - I thought self supporting and large cones were interchangeable, but the table shows slightly different temps for the same rate. How critical are those differences? The Orton Cone Chart can...
Can I speed up my kiln’s cooling cycle?
How can I speed up my kiln's cooling cycle? Question: “What can we do to make big kilns cool down faster? Keep the door slightly open at a certain temperature?” There isn't really a practical way to speed up the cooling cycle. In my free Strategic Glazing class, I...
Why does my kiln fire unevenly?
Why does my kiln fire unevenly? Question: “Why do I get different results on my cone pack based on which shelf-- top, middle, or bottom-- the pack is located?” Our kilns tend to fire unevenly and I've also had the same experience. The new Cone Art kiln that I bought...
Sodium silicate turned my glaze into thick sludge
Can you save a glaze that has turned to pudding after adding too much sodium silicate? Question: I added way too much sodium silicate to two big buckets of glaze. They were too thick and water wasn’t helping so I decided to deflocculate with sodium silicate. They have...