Monthly Tech-Tip from Tony Hansen SignUp

No tracking! No ads!

3D Print a Test of the Beer Bottle Neck
3D Printing a Clay Cookie Cutter-Stamper
A 3-minute Mug with Plainsman Polar Ice
A Broken Glaze Meets Insight-Live and a Magic Material
Accessing Recipes from "Mid-Fire Glazes" book in Insight-Live
Adjusting the Thixotropy of an Engobe for Pottery
Analysing a Crazing, Cutlery-marking Glaze Using Insight-Live
Compare the Chemistry of Recipes Using Insight-Live
Connecting an External Image to Insight-Live Pictures
Convert a Cone 10 Glaze to Cone 6 Using Desktop Insight
Create a Synthetic Feldspar in Insight-Live
Creating a Cone 6 Oil-Spot Overglaze Effect
Creating Rules for Calcium Carbonate - Wollastonite Substitution
Design a Triangular Pottery Plate Block Mold in Fusion 360
Desktop Insight - Difficult Formula to Batch Calcuations
Desktop Insight 1A - Compare Theoretical and Real-World Feldspars
Desktop Insight 1B - Turn a Feldspar Into a Glaze
Desktop Insight 1C - Substitute Wollastonite for Whiting in Glazes
Desktop Insight 2 - Creating a Matte Glaze
Desktop Insight 3 - Dealing With Crazing
Desktop Insight 4 - Add a Native Material to MDT, Build a Glaze
Desktop Insight 5A - Glaze Formula to Batch Calculations
Desktop Insight MDT: Adding a Material
Desktop Insight: Maintain an MDT as a CSV File in Excel
Digitalfire Desktop INSIGHT Overview Part 1
Digitalfire Desktop INSIGHT Overview Part 2
Enter a Recipe Into Insight-live
Entering Shrinkage/Porosity Data Into Insight-Live
Getting Frustrated With a 55% Gerstley Borate Glaze
How I Fixed a Settling Glaze Slurry Using Desktop Insight
How I Formulated a Cone 6 Silky Matte Glaze Using Insight-Live
How to Add Materials to the Desktop Insight MDT
How to Apply a White Slip to Terra Cotta Ware
How to Paste a Recipe Into Insight-live
Importing Data into Insight-live
Importing Desktop Insight Recipes to Insight-live
Importing Generic CSV Recipe Data into Insight-Live
Insight-Live Meets a Silica Deprived Glaze Recipe
Insight-Live Quick Overview
Liner Glazing a Stoneware Mug
Make a precision plaster mold for slip casting using Fusion 360 and 3D Printing
Make test bars to measure pottery clay physical properties
Making ceramic glaze flow test balls
Manually program your kiln or suffer glaze defects!
Mica and Feldspar Mine of MGK Minerals
Predicting Glaze Durability by Chemistry in Insight-Live
Preparing Pictures for Insight-live
Remove Gerstley Borate and Improve a Popular Cone 6 Clear Glaze
Replace Lithium Carbonate With Lithium Frit Using Insight-Live
Replacing 10% Gerstley Borate in a clear glaze
Signing Up at Insight-live.com
Signing-In at Insight-live.com
Slip cast a stoneware beer bottle
Subsitute Gerstley Borate in Floating Blue Using Desktop Insight
Substitute Ferro Frit 3134 For Another Frit
Substituting Custer Feldspar for Another in a Cone 10R Glaze Recipe
Substituting Materials by Weight: Why it does not work!
Substituting Nepheline Syenite for Soda Feldspar
Thixotropy and How to Gel a Ceramic Glaze
Use Insight-live to substitute materials in a recipe
Using Recipe Libraries With Desktop Insight

Use Insight-live to substitute materials in a recipe

We will substitute wollastonite for whiting and a frit for Gerstley borate in the G2571A cone 10 matte while maintaining the chemistry of the original recipe.

A. Insight-live


Click here to watch this at youtube.com or click here to go to our Youtube channel

A two-minute silent video with annotations.

Links

Recipes G2571A - Cone 10 Silky Dolomite Matte glaze
A cone 10R dolomite matte having a pleasant silky surface, it does not cutlery mark, stain or craze on common bodies
Glossary Glaze Gelling
Glaze slurries can gel if they contain soluble materials that flocculate the suspension. Gelling is a real problem since it requires water additions that increase shrinkage.
Typecodes Gerstley Borate Substitutes
Many development efforts to create Gerstley Borate substitutes took place during the early 2000s (the initial period when the demise of Gerstley Borate appeared imminent). A number of companies, including Laguna Clays itself, produced and sold these for many years. When Laguna secured another stockpile at the mine and began producing the original material again, interest in substitutes gradually waned. However, the sudden dramatic price increase in 2023 appears to have initiated the process again. Gillespie Borate appears to be the only viable and visible substitute now. Thus, the substitutes listed here are mostly no longer made. Other high-boron materials shown are also no longer available. We continue to recommend sourcing B2O3 from frits instead. Please contact us if you have a specific recipe and we can work with you in your Insight-live account to develop a new recipe that both eliminates the GB and improves overall working and firing properties.
Typecodes Gerstley Borate Glaze Calculation examples
Examples of how we use glaze calculations (in an Insight-Live.com account) to replace Gerstley Borate with other materials, especially frits, in various glaze recipes. In doing so we take the opportunity to improve the recipe in other ways (e.g. reduce thermal expansion, improve slurry properties, reduce bubbling and crawling).

Colemanite and what its decrepitation does in glazes


Decrepitation refers to a decomposition accompanied by scaling, delayering, even disintegration of the glaze layer. Moving rightward these glazes have increasing percentages of colemanite. At its worst (far right) the glaze is spattering off the sample and onto the kiln shelf. The others are crawling, first pulling away from the corners (far left) moving toward pulling away on the flat surfaces (center). Gerstley Borate and Ulexite, similar minerals, are far less likely to do this (but they have other serious issues also). A much better solution is to use frits to source the oxide B2O3 (easy to do in your account at Insight-live.com). Photos courtesy of Nigel Hicken.

A unfritted tile glaze is boiling and spattering the kiln shelf above


A boiling tile glaze spatters the shelf above

What you are seeing here is strange indeed. On the bottom is a porcelain tile that was glazed using the recipe indicated. Multiple ones of these were stacked into a kiln, each on its own round kiln shelf. During the firing the boiling of the glaze melt was so violent that it splashed upward, coating the undersides of the shelves above them. Yet no glaze was splattered around the tiles themselves! This phenomenon was created and reported by a researcher working on leadless ultra-gloss metallic tile glazes. This recipe is part of a project to create a similar chemistry to previous work done with Fusion Frit FZ-16. Glazes made using that frit do not have this boiling problem and produce surfaces comparable to leaded frits. We speculate that the vigorous melt is a product of the interaction between the high zinc oxide and borax in the recipe.

Original glaze with Gerstley Borate vs. improved version with frit


Two mugs with clear glazes

These pieces are fired at the same temperature. The glaze on the left is a popular recipe found online, Worthington Clear (our code number G2931). The Gerstley Borate in it is "farting" as the glaze is melting (the calculated LOI of the glaze as a whole is 15% mainly from that one material). Unless applied very thinly tons of micro-bubbles appear (this example is fired to cone 03). And strange, it is crazing badly also despite the low calculated thermal expansion. Using my account at insight-live.com I was able to source the B2O3 and MgO from a frit (actually two frits) to create the G2931K recipe. Although the thermal expansion calculates higher it is strangely fitting better (albeit not firing as white). As you can see, the new fritted glaze is very glassy and clear (thick or thin).

By Tony Hansen
Follow me on

Got a Question?

Buy me a coffee and we can talk

 



https://digitalfire.com, All Rights Reserved
Privacy Policy