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Clay Bodies
General Formulation Testing
Firing
General
General
Pottery General Books, Periodicals
Glazes
Food Safety Adjustment, Adaptation Base Glazes Formulation Chemistry Introduction Thermal Expansion Color Trouble Shooting Low Fire General Slip, Engobe
Kilns and Firing
General
Materials
Safety General Toxicity
Testing
General
XML
General
Clay Bodies
Formulation
Formulating a Porcelain
Understanding the functions of each of the major materials in a high temperature porcelain gives you the ability to tune their amounts and choose brand names to make the porcelain you want.
Low Fire White Talc Casting Body Recipe
The classic white ball clay talc casting and modelling recipe has been used for many years. It is a dream to use as long as you are aware of the problems and risks.
Stoneware Casting Body Recipes
Some starting recipes for stoneware and porcelain with information on how to adjust and adapt them
Understanding the Terra Cotta Slip Casting Recipes In North America
This article helps you understand a good recipe for a red casting body so that you will have control and adjustability.
General
Outdoor Weather Resistant Ceramics
How can you be sure that the porosity of your fired ceramic ware is low enough to prevent freeze-thaw breakdown in the winter?
Overview of Paper Clay
A little background information about the origin and an explanation of what paper clay is
Rationalizing Conflicting Opinions About Plasticity
How can two potters have completely different opinions about the plasticity and workability characteristics of the same clay body
Recylcing Scrap Clay
Guidelines for collecting, testing, reprocessing scrap clay in a multi-person ceramic studio.
The Black Art of Drying Ceramics Without Cracks
Anything can be dried if it is done slowly and evenly enough. To dry faster optimize the body recipe, ware cross section, drying process and develop a good test to rate drying performance.
The Whining Stops Here: A Realistic Look at Clay Bodies
Jonathan Kaplan overviews clay bodies, body materials and body types, how they are formulated and tested, how to protect yourself when buying prepared bodies, how to take responsibility.
Testing
Making Clay Test Bars
Being able to make good consistent test bars and fire them in a consistent and proper way is a basic requirement of getting valid results for shrinkage and porosity measurement.
The Physics of Clay Bodies
Learn to test your clay bodies and recording the results in an organized way and understanding the purpose of each test and how to relate its results to changes that need to be made in process and recipe.
Understanding the Deflocculation Process in Slip Casting
Understanding the magic of deflocculation and how to measure specific gravity and viscosity, and how to interpret the results of these tests to adjust the slip, these are the key to controlling a casting process.
Firing
General
Electric Hobby Kilns, How Good Are They?
Electric hobby kilns are certainly not up to the quality and capability of small industrial electric kilns, but if you are aware of the limitations and take precautions they are workable.
Electric Kilns: Some Recent Advances You Should Not Ignore
Electric firing is undergoing a renaissance among potters because of changing attitudes and new equipment.
Eye Injuries Due to Radiation by Edouard Bastarache
Eye Injuries Due to Radiation by Edouard Bastarache
Firing: What Happens to Ceramic Ware in a Firing Kiln
By understanding what sorts of change art taking place in the ware at each stage of a firing you can tune the curve and atmosphere to produce the best possible ware.
Interpreting Orton Cones
Interpreting how high a kiln fired based on the look of the cones can be a much more complicated matter than it might first appear.
Refractory Coatings Offer New Firing Possibilities
In this NCECA 97 Presentation Nils Lou overviews his personal experiences using RFCs over a period of 25 years.
Some Keys to Dealing With Firing Cracks
Ceramic industry can fire much faster and deal with much heavier objects than potters can, how do they do it. The answer is they pay more attention to the basics, it is all common sense and good equipment.
General
Books, Periodicals
Ceramic Art and Industry Periodicals
A list of ceramic industry and art magazines from around the world
Ceramic Book Sources
Ceramic art and technical book sources from around the world
General
Are You in Control of Your Production Process?
Potters often run operations that are on the edge of control and they tolerate production and ware problems that industry would not. However ethics an honesty with yourself will soon or later demand a better knowledge of process and materials.
I've Always Done It This Way!
If you are a potter and have gotten away with pushing the limits in your process for many years there will eventually be a day of reconing. It is better to understand why you do things the way you do and be ready to adjust.
Pottery
Pottery Crash Course for Beginners
Where do you start to teach children about pottery if you have no background in it?
Tiles and Mosaics for Potters
If you are a potter you already know much of what is needed to manufacture tile. However there are some things you need to unlearn to make tile well.
Glazes
Adjustment, Adaptation
A Low Cost Tester of Glaze Melt Fluidity
This device to measure glaze melt fluidity helps you better understand your glazes and materials and solve all sorts of problems.
Reducing the Firing Temperature of a Glaze From Cone 10 to 6
Moving a cone 10 high temperature glaze down to cone 5-6 requires major surgery on the recipe or the transplantation of the color and surface mechanisms into a proven cone 6 base glaze.
Unwanted Crystallization in a Cone 6 Glaze
Someone is having a problem with a cone 6 glaze going glossy and crystallizing, this article rationalizes the problem in terms of chemistry
Base Glazes
G1214M Cone 5-7 20x5 Glossy Base 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.
G1214W Cone 6 Transparent Base Glaze
The process we used to improve the 20x5 base cone 6 glaze recipe
G1214Z Cone 6 Matte Base Glaze
This glaze was developed using the 1214W glossy as a starting point. This article overviews the types of matte glazes and rationalizes the method used to make this one.
G1916M Cone 06-04 Base Glaze
This is a frit based boron base glaze that is easily adjustable in thermal expansion, a good base for color and a starting point to go on to more specialized glazes.
G1947U/G2571A Cone 10/10R Base Matte/Glossy Glazes
These starting recipes use no frits and work in oxidation/reduction and are inexpensive to make. They can be used as bases for the whole range of typical cone 10 pottery glazes (celadon, tenmoku, oatmeal, white matte, brown crystal).
Chemistry
Do You Need to Know About Eutectics to Make a Good Glaze?
This discussion was initiated by a question in July 1998 on Clayart as to whether a knowledge of eutectics would help produce a better glaze.
How INSIGHT Deals With Unity, LOI and Formula Weight
INSIGHT enables you to enter material analyses as recipes as a first step to inserting them into the materials database. Imposing an LOI and understanding how to set unity and its connection for formula weight are important concepts.
Limit Formulas and Target Formulas
Glaze chemistries for each type of glaze have a typical look to them that enables us to spot ones that are non-typical. Limit and target formulas are useful to us if we keep in perspective their proper use.
Understanding Ceramic Oxides
Fired glazes are composed of oxide building blocks. Each of the oxides contributes different properties to the fired glaze and interacts with others in different ways. Understanding these gives you control.
Understanding Glaze Calculation: An Aid to Potters
Bob Kavanagh explains ceramic glaze calculation as a potter for other potters. He deals with theory and show practical examples.
What is a Mole, Checking Out the Mole
An overview of the meaning of this unit for measuring quantities of molecules by Joseph Herbert and Tom Buck.
Color
An Overview of Ceramic Stains
Understanding the advantages of disadvantages of stains vs. oxide colors is the key to choosing the best approach
Formulating a Clear Glaze Compatible with Chrome-Tin Stains
In ceramics color is often a matter of chemistry, that is, the host glaze must be compatible and have a sympathetic chemistry for the stain being added. Chrome-tin stains are a classic example.
Getting the Glaze Color You Want: Working With Stains
There are many things to know about to make the best use of stains, but one often ignored aspect is the relationship between glaze color and chemistry. If you want to control color you need to know about stains and chemistry.
Food Safety
Are Your Glazes Food Safe or are They Leachable?
Many potters do not think about leaching, but times are changing. What is the chemistry of stability? There are simple ways to check for leaching, and fix crazing.
Attack on Glass: Corrosion Attack Mechanisms
Max Richens outlines the various mechanisms by which acids and bases can dissolve glass and glazes. He provides some information on stabilizing glazes against attack.
Crazing and Bacteria: Is There a Hazard?
A post to a discussion on the clayart group by Gavin Stairs regarding the food safety of crazed ware.
How to Liner-Glaze a Mug
A step-by-step process to put a liner glaze in a mug that meets in a perfect line with the outside glaze at the rim.
Is Your Fired Ware Safe?
Glazed ware can be a safety hazard to end users because it may leach metals into food and drink, it could harbor bacteria and it could flake of in knife-edged pieces.
Leaching Cone 6 Glaze Case Study
An example of how we can use INSIGHT software to determine of a glaze is likely to leach
Formulation
Alberta Slip, 20 Years of Substitution for Albany Slip
Alberta Slip makes a great base for glazes because not only is it almost a complete glaze by itself but it has low thermal expansion, it works well with frits and slurry properties can be adjusted.
Chemistry vs. Matrix Blending to Create Glazes from Native Materials
Is it better to do trial and error line and matrix blending of materials to formulate your glazes or is it better to use ceramic chemistry?
Creating Your Own Budget Glaze
How to take a stockroom full of unused materials and turn them into a good glase. This article helps you appreciate that the glaze formula is the important thing, you can use any number of materials to supply the oxides.
Formulating Ash and Native-Material Glazes
How to have a volcanic ash analysed and them use ceramic chemistry to create a glaze that contains the maximum possible amount of the ash for the desired effect
Variegating Glazes
This is an overview of the various mechanisms you can employ to make glazes dance with color, crystals, highlights, speckles, rivulets, etc.
General
Ball Milling Glazes
Every industry ball mills their glazes as standard practice, no one ever questions the need. Yet few potters do. Maybe it is time you should think about it.
Ceramic Glazes Today
Todd Barson of Ferro Corp. overviews the glaze formulations being using in various ceramics industry sectors. He discusses fast fire, glaze materials, development and trouble shooting.
Cone 6 Floating Blue Glaze Recipe
A discussion by Jonathan Kaplan on dealing the with fickle nature of this glaze
Copper Red Glazes
A study of the mechanism behind the color in color red glazes by Karl Platt.
Crystal Glazes: Understanding the Process and Materials
Fara Shimbo's book on crystal glazes is the most understandable and practical we have seen. The book is full of color pictures and test tiles.
Floating Blue: The Most Popular Cone 6 Glaze
Inspite of the fact it is very fickle, the floating blue cone 6 glaze is a good example of a recipe that displays many different kinds of variegation. Gerstley borate is one of the main reasons for its properties.
Low Budget Testing of the Raw and Fired Properties of a Glaze
There is more to glazes than their visual character, they have other physical properties like hardness, thermal expansion, leachability, chemistry and they exhibit many defects. Here are some simple tests.
Painting Glazes Rather Than Dipping or Spraying
Potters who are used to dipping and spraying glazes might be surprised to learn how well glazes can paint on if they have enough gum in the recipe.
Super-Refined Terra Sigillata
Vince Pitelka describes his method of preparing a Terra Sigillata slip.
The Trials of Being the Only Technical Person in the Club
If you are the only technically oriented person in your company, school or pottery club you will get a charge out of this report from a right-brained potter always fighting to drag others into understanding glazes.
Two Good Technical Books for Ceramics
Tony Hansen's opinion of two good technical books for people who want to understand how glazes work.
What Determines a Glaze's Firing Temperature?
By understanding how glazes melt and materials and chemistry interplay to determine behavior and temperature of melting and testing degree of melt you control the melting temperature of your glazes.
Why Textbook Glazes Are So Difficult
The trade is glaze recipes has spawned generations of potters going up blind alleys trying recipes that don't work and living with ones that are much more trouble than they are worth. It is time to leave this behind and take control.
Introduction
Ceramic Chemistry Basics - Formula, Analysis, Mole%, Unity, LOI
Part of changing your viewpoint of glazes from a collection of materials to a collection of oxides is learning what a formula and analysis are, now conversion between the two is done and how unity and LOI impact this.
Changing Our View of Glazes
A big secret to getting control of glazes is to begin looking at them as formulas of oxides rather than recipes of materials.
Concentrate on One Good Glaze
It is better to understand and have control of one good base glaze than be at the mercy of dozens of imported recipes that do not work. There is a lot more to being a good glaze than fired appearance.
Fighting the Glaze Dragon
At Digitalfire we promote the idea of understanding and formulating your own glazes so you have control rather than relying on suppliers or the trade in glaze recipes.
Glaze Recipes: Formulate Your Own Instead
The only way you will ever get the glaze you really need is to formulate your own. The longer you stay on the glaze recipe treadmill the more time you waste.
Identifying Glaze Mechanisms
If you can look at a glaze recipe and pick out the materials add to produce the color, opacity and variegation you can transplant these into your own base glaze
The Four Levels on Which to View Ceramic Glazes
By knowing which level to view a glaze from you are much better equipped to understand and control it. The levels are process, recipe, material, oxide.
The Potter's Prayer
I composed this prayer for potters who wish to continue down the road of text book glaze recipes, endlessly mixing recipes and never really getting what they want, most of all never getting control.
What is the Glaze Dragon?
At Digitalfire we use a Dragon to personify the kinds of thinking that prevent potters, educators and technicians from understanding and therefore controlling their glazes.
Where Do I Start?
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.
Low Fire
First You See It Then You Don't: Raku Glaze Stability
Tom Buck discusses the change in color over time that can happen with some raku glazes
The Majolica Earthenware Process
Understanding the advantages and disadvantages of low fire ware and the chemistry of physics of the glazes and bodies used is a key factor to exploiting this type of ceramics
Slip, Engobe
Creating a Non-Glaze Ceramic Slip or Engobe
It is difficult to find a slip that is drying and fired compatible with your body. It is better to understand, formulate and tune your a slip to your own body, glaze and process.
Thermal Expansion
Adjusting Glaze Expansion by Calculation to Solve Shivering
This page demonstrates how you might use INSIGHT software to do calculations that will help you increase the thermal expansion of a glaze while having minimal impact on other properties.
Bringing Out the Big Guns in Craze Control: MgO (G1215U)
MgO is the secret weapon of craze control. If your application can tolerate it you can create a cone 6 base glaze of very low thermal expansion that is very resistant to crazing.
Crazing in Stoneware Glazes: Treating the Causes, Not the Symptoms
Band-aid solutions to crazing are often recommended by authors, but these do not get at the root cause of the problem, a thermal expansion mismatch between glaze and body.
Demonstrating Glaze Fit Issues to Students
Glaze and body can both be adjusted to solve crazing and shivering problems. This describes a simple project to create body glaze combinations guaranteed to craze and shiver to demonstrate the principles involved.
The Effect of Glaze Fit on Fired Ware Strength
The fit between body and glaze is like a marriage, if is is strong the marriage can survive problems. Likewise ceramic ware with well fitting glaze is much stronger than you think it might be, and vice versa.
Thermal Expansion Dilatometer Testing Service at Digitalfire
Digitalfire Corporation announces a web site to learn about, arrange for and accept delivery of co-efficient of thermal expansion dilatometer test results for ceramic glazes and clay bodies.
Understanding Thermal Expansion in Ceramic Glazes
The way to deal with crazing or shivering is to understand what thermal expansion is, how it relates to the chemistry to the glaze and practical ways to calculate it. There is a rich mans and poor mans way to fit glazes.
Trouble Shooting
Dealing With Glaze Blisters
Questions and suggestions to help you reason out the cause of ceramic glaze blistering problems and work out a solution
Dealing With Glaze Slurry Properties
It is possible to have a glaze slurry that is a joy to use, but only if you understand the physics of the materials in the glaze recipe.
Dealing With the Problem of Powdering and Cracking Glazes
Powdering and dusting glazes are a dust hazard, nuisance and impediment to ware quality. Shrinkage and cracking on glaze drying can shut you down. Both have the same cause.
Embarrassed in the Pink: Stopping Chrome Flashing
The development of chrome tin pinks in a combination of the stain the the right chemistry in the host glaze. Likewise, unwanted pink flashed can be eliminated by creating a hostile chemistry in the glaze.
Glaze is Off-Color
Questions to ask and strategies to try in dealing with glazes that do not fire the expected color
Glaze Marks or Scratches
Questions to ask and strategies to try to deal with glaze cutlery marking, that is, glazes that are too easily scatched by metal.
Troubleshooting Glaze Crawling
Asking yourself the right questions to figure out the cause of a glaze crawling problem.
Troubleshooting Glaze Crazing
Questions to ask and ways to analyse crazing problems so that you can derive a strategy to deal with the problem correctly.
Troubleshooting Glaze Pinholing, Pitting
Questions to ask and ways to analyse glaze pinholing, pitting problems.
Kilns and Firing
General
Can Potters Learn About Firing Gas Kilns From Industry?
There is a big gap between industrial and studio gas kiln technology. Even the basic theory behind how to construct and file are different. Can potters learn?
Materials
Ceramic Material Nomenclature
One can look at a ceramic material from a mineral, physical or chemical standpoint. Each viewpoint is appropriate depending on the context, understanding this is a key to exploiting materials properly.
Duplicating Albany Slip
How Alberta Slip was created by analysing and duplicating the physical and chemical properties of Albany Slip
Duplicating AP Green Fireclay
Few people actually understood what AP Green fireclay really was (it is no longer available). By carefully ascertaining its physical properties we were able to formulate a substitute material mix.
How a Material Chemical Analysis is Done
Michael Banks and Stuart Altmann talk about chemical analyses methods and their advantages and disadvantages. Also information on testing labs you can use.
Substituting Cornwall Stone
How to create a blend of materials to chemically substitute for another (Cornwall Stone is used as an example).
Those Unlabeled Bags and Buckets
Mike Bailey and David Hewitt provide detailed information on how to identify materials from the properties of their powders
Understanding Ceramic Materials
Ceramic materials are not just powders, they have a physical presence that make each unique and amazing. We cannot adequately describe the properties using just numbers, thinking in terms of generic materials is a key.
Volcanic Ash
Joseph Herbert overviews the technical and practical aspects of this interesting group of materials
Safety
Alumina Hazards by Edouard Bastarche
An overview of the hazards of alumina
Ammonia and Latex Toxicity
Ammonia is a constituent of rubbers and latexes and resist used in ceramics and this is a discussion of its toxicity.
BARIUM and COMPOUNDS / Toxicology - Edouard Bastarache
BARIUM and COMPOUNDS / Toxicology - Edouard Bastarache
Boron Compounds and Their Toxicity by Edouard Bastarche
Toxicity of Boron by Edouard Bastarche
Cadmium: Prevention / Screening Strategy
Toxicity considerations of cadmium compounds in the ceramic industry
Calcium Carbonate Toxicity by Edouard Bastarache
Overview of the hazards associated with the use of calcium carbonate in ceramics
Carbon Monoxide by Edouard Bastarache
A very detailed discussion of the toxicity of carbon monoxide in ceramics
CHROMIUM and COMPOUNDS by Edouard Bastarache
CHROMIUM and COMPOUNDS Toxicity by Edouard Bastarache
COBALT and CERAMICS by Edouard Bastarache
COBALT and CERAMICS Toxicity by Edouard Bastarache
COPPER & COMPOUNDS by Edouard Bastarache
COPPER & COMPOUNDS Toxicity by Edouard Bastarache
Creativity and Illness by Dierdre O’Reilly
A story of one persons struggle with manganese toxicity
Cryolite and Ceramics
Toxicity issues related to ceramics with the mineral Cryolite
Dealing With Dust in Ceramics
A checklist of for changes and additions to your tools and equipment and suggestions for habit changes you need to make to control dust
Did We Learn From Lead?
The long slow death of lead use in ceramics taught us some lessons. Manufacturers who still use acid tests to determine glaze toxicity risk liability.
DIOXINS in CLAYS by Edouard Bastarache
DIOXINS in CLAYS by Edouard Bastarache
ÉTAIN et Dérivés Inorganiques
Fighting Micro-organisms in Ceramics - Edouard Bastarache
Fighting Micro-organisms in Ceramics - Edouard Bastarache
Hafnium Oxide Toxicty by Edourard Bastarche
Overview of toxicity of Hafnium by Edourard Bastarche
Having Your Glaze Tested for Toxic Metal Release
Having Your Glaze Tested for Metal Release
Health & Safety Information Sources
Health & Safety Information Sources
Inorganic Lead and Ceramics by Edouard Bastarache
Inorganic Lead and Ceramics by Edouard Bastarache
Iron oxide and Hematite by Edouard Bastarache
Fe occurs in a number of natural forms, it is abundant in nature and an essential metal, however it can pose certain health hazards.
LITHIUM in Ceramics by Edouard Bastarache
The toxicity of lithium in ceramics is a hotly debated subject, especially with regards to handling raw lithium carbonate, but also with reference to leaching from glazes.
MAN-MADE VITREOUS FIBERS (MMVF) - Edouard Bastarache
MAN-MADE VITREOUS FIBERS (MMVF) - Edouard Bastarache
Manganese Inorganic Compounds Toxicology - Edouard Bastarache
Manganese can be very toxic, expecially with regards to inhalation of the fumes during kiln firing. This material must be treated with care.
MOLYBDENUM and COMPOUNDS - Edouard Bastarache
MOLYBDENUM and COMPOUNDS - Edouard Bastarache
My Story of Manganese and Parkinsons: Jane Watkins
A person story about manganese poisoning.
Nickel Compounds Toxicity by Edouard Bastarche
The ceramic toxicity of nickel in its various forms
Niobium Oxide Toxicity
Toxitcity information from Edouard Bastarache
Occupational Dermatoses - Edouard Bastarache
Occupational Dermatoses in Ceramics by Edouard Bastarache
Overview of Material Safety by Gavin Stairs
Toxicology and ceramic materials is a complex subject, what materials and methods pose the greatest dangers, which are the safest?
Potters Manganese Toxicity by Elke Blodgett
A story of one persons struggle to identify and deal with manganese toxicity
Quartz Toxicity
Quartz is one of the most dangerous materials used in ceramics, yet it is the most abundant, irreplacable, we must learn to use it safely.
SILICOSIS and SCREENING by Edouard Bastarache
SILICOSIS and SCREENING by Edouard Bastarache
Stannous Chloride Toxicity
Overview by Edouard Bastarache
Strontium Carbonate Toxicity
Strontium Carbonate Toxicity by Edouard Bastarache
The Use of Barium in Clay Bodies
Hazards of barium carbonate, considerations regarding its use in clay bodies for precipitation of soluble salts
THORIUM Dioxide Toxicity by Edouard Bastarache
Overview of the hazards associated with the use of thorium dioxide in ceramics
TIN and Inorganic Compounds
Information about the toxicity of tin metal and the various tin containing powders used in industry by Edouard Bastarche
TITANIUM DIOXIDE by Edouard Bastarache
An overview of the safety issues surrounding the use of titanium dioxide
Toxicity of Rare Earth Compounds by Eduoard Bastarche
Toxicity information from Edouard Bastarche
Understanding Acronyms Used on MSDS Sheets
Understanding the meaning and purpose of acronyms used on materials safety database sheets for ceramic minerals
URANIUM and CERAMICS by Edouard Bastarache
URANIUM and CERAMICS by Edouard Bastarache
Vanadium and Compounds - Edouard Bastarache
Vanadium and Compounds - Edouard Bastarache
Zinc Compounds by Edouard Bastarche
Overview of toxicity of zinc compounds
ZIRCONIUM and compounds
An overview of zironcium compounds and hazards associated with their use
ZIRCONIUM et Composés
An overview of zircon compounds and their toxicity in French
Toxicity
Being Realistic About Toxicity and Safety in Ceramics
The materials you use present two hazards you need to think about, are they poisoning your while working with them and are they destabilizing your glazes so they dissolve into food and drink?
Diatomaceous Earth Toxicity by Edouard Bastarache
The hazards of using diatomaceous earth and amorphous silica in ceramics
Hydrofluoric Acid Toxicity by Edouard Bastarche
Hydrofluoric acid is used for etching and engraving in Ceramics and Glassware
Potassium Carbonate Toxicity by Edouard Bastarche
Toxicity of potassium carbonate related to its use in ceramics and pottery
Toxicity of Firebricks Used in Ovens
Toxicity concerns about the use of firebrick or alumina brick to make ovens used for baking bread
Testing
General
Particle Size Distribution of Ceramic Powders
Understanding the theory behind sieve selection, how to properly sample a powder and how to carry out a particle size distribution test can give you valuable information about a material.
XML
MML Materials Markup Language
XML is the futre of ceramic material and testing information. This is a standard electronic medium of exchange in the science and financial world.
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