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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 You in Control of Your Production Process?
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)
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 Base Glaze
G1214W Cone 6 Transparent Base Glaze
G1214Z Cone 6 Matte Base Glaze
G1916M Cone 06-04 Base Glaze
G1947U/G2571A Cone 10/10R Base Matte/Glossy Glazes
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, LOI
Glaze chemistry using a frit of approximate analysis
Glaze Recipes: Formulate Your Own Instead
Glaze Types, Formulation and Application in the Tile Industry
Having Your Glaze Tested for Toxic Metal Release
High Gloss Glazes
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
How to Liner-Glaze a Mug
I've 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 the Raw and Fired Properties of a Glaze
Low Fire White Talc Casting Body Recipe
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
Overview of Paper Clay
Painting Glazes Rather Than Dipping or Spraying
Particle Size Distribution of Ceramic Powders
Porcelain Tile, Vitrified or Granito 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
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 Physics of Clay Bodies
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
Variegating Glazes
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

Cone 6 Floating Blue Glaze Recipe


A discussion by Jonathan Kaplan on dealing the with fickle nature of this glaze


The following is a submission from Jonathan Kaplan to the Clayart discussion group on the Internet.

I've been a participant on this list for probably 5 years or so, and it amazes me that for this length of time, there are many re-occurring topics, not to mention perhaps the most popular one, "RE: Floating Blue." And of course, there are many others, too numerous to mention, but its the nature of the list, and that's OK. But I am troubled with the threads on "Floating Blue" and I'll tell you why.

Seems to me that this is a fickle glaze, to say the least, fires in the neighborhood of cone 6 oxidation and when it works, gives a blue with some interesting surface activity, sometimes called a "reactive" glaze. Also,it's apparent to me that this glaze gives a reduction type surface in an electric kiln, which we all really know fires in a neutral atmosphere. What is most obvious to me in reflecting back on years of this post, including some of Ron's adjustments that when it works, it works fine, which is not very often, and when it doesn't work, it has been called many nasty things, one of the most recent calling it snot green. Whatever. And my sense is that it doesn't work most of the time at least in the comments that I have read on the list. So I am prompted to ask why are you struggling with this glaze, loosing pots over and over in a valiant struggle to obtain this surface? Sure I know that many are not able to have a gas kiln, and that's fine. But to continue to butt heads with this glaze seems to me counter productive, to say the least. So what to do? I'm hearing it now, "God, I really want that funky runny surface active glaze with lots going on in my electric kiln but this Floating Blue is driving me nuts." "And here's Jonathan putting in his 2 cents." Or something like that.

Let me propose the following suggestions. I preface this by including here that as a custom production shop for the ceramics industry including the pottery, giftware, tabletop, etc. segments of this field, we work throughout the temperature spectrum and in any atmosphere. Let me postulate that a surface reminiscent of "Floating Blue" is very obtainable without the struggle of using "Floating Blue" at mid range temperatures in an electric kiln. We do it weekly for clients. While I am not at liberty to post formulas that would violate my non disclosure agreements with my clients, here are some ways to achieve this "elusive" surface.

1. Layering glazes. To develop surface depth and activity, layer glazes either by dipping, pouring, or spraying. Of course, you have run many tests before committing a large body of work, haven't you?

2. Use a slip glaze underneath your glaze to develop a breaking surface, or use a slip glaze over your glaze. We have used a glaze that is mostly Barnard slip with some additions over a one of our glazes to produce a fabulous variegated surface with incredible depth (and yes, blue or blue grey/green) at cone 4 in the electric kilns.

3. Combine two glazes in a line blend. Trust me, some of our most successful surfaces have resulted from this simple task.

4. Use commercial glazes for your temperature range over your shop glazes for either a full coating or for decoration.

5. Diversify the fluxes in your formula. We use several base glazes at cone 5-6 that contain Fusion frits as well as spars.

6. Take a glaze that fires at a higher temperature and re-calculate it to fire at your temperature.

7. Combine some or all of the above suggestions, and of course, test test test.

8. And finally, eliminate "Floating Blue" as you may know it, from your glaze repertoire, and concentrate on not trying to duplicate the reduction look in an electric kiln. Use and exploit the electric kiln for its virtues and incredible firing

Editors Note:

To expand somewhat on Mr. Kaplans comments we could offer the following pointers:

Floating Blue May Not Be Dead!

Since Gerstley Borate is no longer available this whole issue may seem to be a moot point. However Floating Blue works well with Boraq, a Gerstley Borate substitute that you can find out more about at The availability of this material has fostered the study of Gerstley Borate and the whole idea of a plastic borate. It seems we did not appreciate this material while we had it. For more information visit

Related Information


Recipes G2587 - Floating Blue Cone 5-6 Original Glaze Recipe
Floating Blue is a classic cone 6 pottery glaze recipe from David Shaner. Because of the high Gerstley Borate content it is troublesome, difficult. But there are alternatives.

By Tony Hansen

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