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A Low Cost Tester of Glaze Melt Fluidity
A One-speed Lab or Studio Slurry Mixer
A Textbook Cone 6 Matte Glaze With Problems
Adjusting Glaze Expansion by Calculation to Solve Shivering
Alberta Slip, 20 Years of Substitution for Albany Slip
An Overview of Ceramic Stains

Are Your Glazes Food Safe or are They Leachable?
Attack on Glass: Corrosion Attack Mechanisms
Ball Milling Glazes, Bodies, Engobes
Binders for Ceramic Bodies
Bringing Out the Big Guns in Craze Control: MgO (G1215U)
Can We Help You Fix a Specific Problem?
Ceramic Glazes Today
Ceramic Material Nomenclature
Ceramic Tile Clay Body Formulation
Changing Our View of Glazes
Chemistry vs. Matrix Blending to Create Glazes from Native Materials
Concentrate on One Good Glaze
Copper Red Glazes
Crazing and Bacteria: Is There a Hazard?
Crazing in Stoneware Glazes: Treating the Causes, Not the Symptoms
Creating a Non-Glaze Ceramic Slip or Engobe
Creating Your Own Budget Glaze
Crystal Glazes: Understanding the Process and Materials
Deflocculants: A Detailed Overview
Demonstrating Glaze Fit Issues to Students
Diagnosing a Casting Problem at a Sanitaryware Plant
Drying Ceramics Without Cracks
Duplicating Albany Slip
Duplicating AP Green Fireclay
Electric Hobby Kilns: What You Need to Know
Fighting the Glaze Dragon
Firing Clay Test Bars
Firing: What Happens to Ceramic Ware in a Firing Kiln
First You See It Then You Don't: Raku Glaze Stability
Fixing a glaze that does not stay in suspension
Formulating a body using clays native to your area
Formulating a Clear Glaze Compatible with Chrome-Tin Stains
Formulating a Porcelain
Formulating Ash and Native-Material Glazes
G1214M Cone 5-7 20x5 glossy transparent glaze
G1214W Cone 6 transparent glaze
G1214Z Cone 6 matte glaze
G1916M Cone 06-04 transparent glaze
Getting the Glaze Color You Want: Working With Stains
Glaze and Body Pigments and Stains in the Ceramic Tile Industry
Glaze Chemistry Basics - Formula, Analysis, Mole%, Unity
Glaze chemistry using a frit of approximate analysis
Glaze Recipes: Formulate and Make Your Own Instead
Glaze Types, Formulation and Application in the Tile Industry
Having Your Glaze Tested for Toxic Metal Release
High Gloss Glazes
Hire Us for a 3D Printing Project
How a Material Chemical Analysis is Done
How desktop INSIGHT Deals With Unity, LOI and Formula Weight
How to Find and Test Your Own Native Clays
I have always done it this way!
Inkjet Decoration of Ceramic Tiles
Is Your Fired Ware Safe?
Leaching Cone 6 Glaze Case Study
Limit Formulas and Target Formulas
Low Budget Testing of Ceramic Glazes
Make Your Own Ball Mill Stand
Making Glaze Testing Cones
Monoporosa or Single Fired Wall Tiles
Organic Matter in Clays: Detailed Overview
Outdoor Weather Resistant Ceramics
Painting Glazes Rather Than Dipping or Spraying
Particle Size Distribution of Ceramic Powders
Porcelain Tile, Vitrified Tile
Rationalizing Conflicting Opinions About Plasticity
Ravenscrag Slip is Born
Recylcing Scrap Clay
Reducing the Firing Temperature of a Glaze From Cone 10 to 6
Simple Physical Testing of Clays
Single Fire Glazing
Soluble Salts in Minerals: Detailed Overview
Some Keys to Dealing With Firing Cracks
Stoneware Casting Body Recipes
Substituting Cornwall Stone
Super-Refined Terra Sigillata
The Chemistry, Physics and Manufacturing of Glaze Frits
The Effect of Glaze Fit on Fired Ware Strength
The Four Levels on Which to View Ceramic Glazes
The Majolica Earthenware Process
The Potter's Prayer
The Right Chemistry for a Cone 6 MgO Matte
The Trials of Being the Only Technical Person in the Club
The Whining Stops Here: A Realistic Look at Clay Bodies
Those Unlabelled Bags and Buckets
Tiles and Mosaics for Potters
Toxicity of Firebricks Used in Ovens
Trafficking in Glaze Recipes
Understanding Ceramic Materials
Understanding Ceramic Oxides
Understanding Glaze Slurry Properties
Understanding the Deflocculation Process in Slip Casting
Understanding the Terra Cotta Slip Casting Recipes In North America
Understanding Thermal Expansion in Ceramic Glazes
Unwanted Crystallization in a Cone 6 Glaze
Volcanic Ash
What Determines a Glaze's Firing Temperature?
What is a Mole, Checking Out the Mole
What is the Glaze Dragon?
Where do I start in understanding glazes?
Why Textbook Glazes Are So Difficult
Working with children

Are You in Control of Your Production Process?


Potters often run operations that are on the edge of control tolerating production and ware problems that industry would not. However ethics will sooner or later demand a better knowledge of process and materials.


Have you ever blissfully ignored the possible consequences of less than ideal production methods, then acted surprised when a day of reckoning came? When forced to look previous mistakes in the face, it often turns out that past problems, which appeared small and unrelated, have come together to cause major headaches.

A production facility cannot be operated on luck; it must be run with an understanding of the materials and processes. Each facet of a production line has a set goal and is like a highway. But remember, for every mile of highway there are two miles of ditch! If you understand and control the processes and materials, then you proceed down that highway in a relatively straight line. If not, you zig-zag more and more until you hit the ditch. Typically, a problem has a dizzying array of contributing factors and the 20:20 vision of hindsight usually testifies to how many things could have been done differently.

When things are going well, it is a joy to unload the kiln. But when a glaze problem hits, "crisis management mode" kicks in and everyone suddenly becomes very interested in glaze chemistry! There is a much more direct relationship between glaze chemistry and fired results than between glaze recipe and fired results. So if you are having a problem with fired ware, then chemistry might be an important factor in solving it properly.

How close are you to encountering a ceramic related problem or product liability that could endanger everything you have worked for. It is typical for small-scale ceramic operations to have much less than 'complete control'. For example:

Potteries stretched to the limit are on the 'edge of control' already and are ill-equipped to deal with unexpected problems and often unable to diagnose the true cause. Many tend to be stuck in an "I've always done it this way and it worked before" way of thinking.

Some think that the pottery and ceramic slip-casting businesses are similar. But they are not. In the ceramic shops everyone uses the same clay body, the same slip recipe, the same jars of glaze, the same temperature, the same kilns. The big manufacturers of suppliers for that industry have a 'level playing field' and they have worked out the problems so that people without ceramic knowledge can make ware successfully. But in pottery the only thing that is the same is that everyone does it different.

To reduce your liability if someone is hurt with your ware you must be able to demonstrate that you are qualified, conscientious about making safe ware (i.e. testing, consulting experts) and that you deal quickly with complaints.

I don't have any magic solutions but here are a few suggestions to help you 'protect your butt'.

Increase your knowledge of your materials and process

If you can answer the following questions then you will be a better position to solve problems related to each.

A change in thinking

You might feel that doing things one way has always worked, but did it really? Maybe your ware has been deficient in a certain way all along and you didn't see it. Maybe you have been lucky in the past, maybe your way of doing things doesn't 'scale up' well, maybe the only thing that kept you from falling off the edge was luck. Pottery is a very complex business, no one person can know it all. Be ready to accept suggestions and but get the reasoning behind them so you know why you do things the way you do.

Don't bite off more than you can chew

We have all had to 'eat crow' after being unable to make pieces we promised someone because our way of doing things just did not work with that type of ware? Never commit to doing a type of product unless you've actually done it already and done it over a period of time. Moving to another temperature range, for example, is a really big deal, don't underestimate it.

Recognize your responsibility

Be very cautious about making cookware or ware to be used on top of the stove. No matter what anyone says, an ordinary clay body is just not good enough for ware that must withstand sudden changes in temperature. You can be open to liability if someone expects the same thermal shock performance from your products as Corningware and then burns them self. Contact your clay supplier to get a body intended for this, but be ready to make some compromises in order to use it.

Don't be smug and think that because your stuff is beautiful you are exempt from concerns and hardness, strength, porosity, leaching, thermal shock resistance, chip resistance, glaze fit of your product. Some of these relate to safety concerns for your customers, all relate to the your reputation and that of the entire pottery community. Simple tests are within your reach to address these matters and you should know about them.

Related Information


Projects Tests
Glossary Leaching
Ceramic glazes can leach heavy metals into food and drink. This subject is not complex, there are many things anyone can do to deal with this issue
By Tony Hansen
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