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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

Predicting Glaze Durability by Chemistry in Insight-Live

How to spot out-of-balance indicators in the chemistry of ceramic glazes that suggest susceptibility to scratching or cutlery marking.

A. Insight-live


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

I have a glaze that is scratching, cutlery marking. Why? Could the reasons be the chemistry? In this video I am going to look at the oxide makeup (using Insight-live) to see if I can answer that. Following is a transcript of the video.

Cone 10 Cutlery Marking Glaze
Gersley Borate 11.364
Dolomite 6.182
Whiting 8.182
Custer Feldspar 26.636
Kaolin (EPK) 6.182
Talc 12.273
Silica 21.909
Superpax 7.273

Go to Insight-Live (I am already signed in).
Add new recipe.
Show the Import box, Paste (ctrl-v), Confirm and Interpret.

Two materials are not linking to a material in the materials database.
Search EPK, it is a reference material, show which names can be used.
Gerstley, spelled wrong.
Edit, fix names, Save and Done editing.

What does the chemistry of a typical cone 10 glaze look like?
Advanced Search, Limits, Search, choose Green and Cooper.

These are materials, these are oxides.
Materials decompose to oxides during firing.
Oxide arrange themselves into the glass structure as the kiln cools.
Stable structures happen when their relative amounts are within some sort of reasonable proportions.
These limits are about what a strong, wear resistant glass looks like.

MgO: High
Al2O3: Super low (half the minimum)
SiO2: Far below the minimum

Compare with a base cone 6 transparent and matte (even lower than them).

Why is it not melting and running down off the ware? The high MgO is stiffening the melt.
This is likely a special purpose reactive glaze, but it is clear best for decorative surfaces, not functional.

Is this likely to leach? Yes.
The strength and hardness and SiO2 and Al2O3 impart also produces a more stable and therefore less-leaching surface.

Links

Glossary Cutlery Marking
Ceramic glazes that mark from cutlery are either not properly melted (lack flux), melted too much (lacking SiO2 and Al2O3), or have a micro-abrasive surface that abrades metal from cutlery.
Troubles 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.
Oxides Al2O3 - Aluminum Oxide, Alumina
Oxides SiO2 - Silicon Dioxide, Silica

Cutlery marking here is directly related to the chemistry of the glaze


This is an example of cutlery marking in a cone 10 silky matte glaze lacking Al2O3, SiO2 and having too much MgO. Al2O3-deficient glazes often have high melt fluidity and run during firing, this freezes to a glass that lacks durability and hardness. But sufficient MgO levels can stabilize the melt and produce a glaze that appears stable but is not. Glazes need sufficient Al2O3 (and SiO2) to develop hardness and durability. Only after viewing the chemistry of this glaze did the cause for the marking become evident. This is an excellent demonstration of how imbalance in chemistry has real consequences. It is certainly possible to make a dolomite matte high temperature glaze that will not do this (G2571A is an example, it has lower MgO and higher Al2O3 and produces the same pleasant matte surface).

Click here for case-studies of Insight-Live fixing problems


Insight-live help button

You will see examples of replacing unavailable materials (especially frits), fixing various issues (e.g. running, crazing, settling), making them melt more, adjusting matteness, etc. Insight-Live has an extensive help system (the round blue icon on the left) that also deals with fixing real-world problems and understanding glazes and clay bodies.

By Tony Hansen
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