A high-nepheline, zero-silica cone 8 silky matte glaze is cutlery marking and crazing. Why?
I will show you how found a recipe on Facebook, assessed it, substituted my own materials, tested it, adjusted it. Now it is like a cone 10 dolomite matte.
How I found a recipe on Facebook, substituted a frit for the Gerstley Borate and added the extra silica it needed to fight crazing. I got a fabulous cone 6 clear.
Using Insight-live I will demonstrate the surprising amount of silica some cone 6 base glazes that appear OK will accept and still melt well.
How to spot out-of-balance indicators in the chemistry of glazes that suggest susceptibility to scratching or cutlery marking.
Raw lithium carbonate can be replaced with a lithium-containing frit if you can do the chemistry. And you can at insight-live.com.
Use Insight-Live.com to do major surgery on a feldspar saturated cone 10R glaze recipe with multiple issues: blistering, pinholing, crazing, settling, dusting and possibly leaching!
The test bars will measure fired porosity and shrinkage over a range of temperatures, drying shrinkage, LOI and pugged water content. They follow procedures defined in Insight-live.com.
How to reference a picture from an external website like flickr.com from within a recipe in Insight-live
A short annotated video of how to create an account at insight-live.com
A short annotated video of how to sign-in to a personal account at insight-live.com
How to import the Digitalfire Insight recipe database file (INSIGHTDATA.DB) and the pictures that attach to recipes therein
Using help, your account, renewal and preferences pages, the managers and panels, recipes, materials, entering a recipe, chemistry, downloading desktop Insight.
How to find them, duplicate them and develop them within your account at insight-live.com
If your recipe is on the clipboard, this shows you how to import it into Insight-live and make adjustments after.
Learn how to add a recipe, title it, add lines and change them, set lines to added status, enter notes and pictures and print a mix ticket
An example of how to enter test results from your ceramic testing into recipes in your account at insight-live.com.
How to take a picture using an iPhone, crop and resample it, save it, then upload it to a recipe.
How to import data from desktop Insight, GlazeMaster, Matrix, GlazChem, HyperGlaze, Generic Spreadsheet CSV into your account at insight-live.com.
How to add and override material data and how to do chemistry calculations in your account at insight-live.com.
How to organize your recipes into a worksheet of recipe rows and material columns, save it as a CSV file and import into Insight-Live.com
A video tour of all the major features of the Digitalfire Insight-Live.com online recipe, material, test and picture manager.
A tour around the home page. Where to start.
I will show you some secrets of making a base engobe (or slip) apply to leather hard terracotta ware in a thick, perfectly even layer.
I will show you how to glaze a mug with a liner glaze inside and a colored one outside so that they meet in a perfect line at the rim.
To do a drop-and-hold firing you must manually program your kiln controller. It is the secret to surfaces without pinholes and blisters.
I will show you why people love/hate this material and how I substituted it for Ulexite to make a much easier-to-use glaze that fires just as good or better.
Making 10 gram balls of your glaze and firing them on 2in by 2in tiles is a great way to evaluate their flow, surface and susceptibility to defects.
I will show you why thixotropy is so important. Glazes that you have never been able to suspend or apply evenly will work beautifully.
D. Desktop Insight
Part two of a complete tour. It includes using targets, setting calculation types, entering recipe notes and details, SQLite and a review the menus.
Part one of a complete tour. The anatomy of the recipe window, how to open, edit and save recipes; the materials, oxides and supply oxide dialogs, the MDT.
Learn to how to download a recipe library from your account at Insight-live and open and explore it using desktop Insight
Compare calcium carbonate (whiting) with other sources of CaO (dolomite, wollastonite, frit), learn to understand the chemistry differences between materials and then substitute wollastonite for whiting in a specific recipe.
While comparing a real-world and theoretical feldspar learn to enter, edit, save, normalize recipes and the materials dialog. Glaze chemistry concepts.
Learn to compare a target formula with the chemistry of a feldspar. See why it does not make a good glaze by itself and what materials need to be added to make it into a balanced glaze.
Learn to do difficult formula to batch conversions. Learn mole%, finding frits by chemistry, Na2O sourcing, oxide oversupply, recipe line added status, overriding in the Supply dialog, when to compromise an exact match.
Learn to add a native volcanic ash to the INSIGHT materials database (MDT) and then create a glaze from it maximizing its percentage. Learn to impose an LOI on a material and why this method is better than line blending.
Learn to use a non-unity calculation to convert a formula into a batch recipe using theoretical and real-world materials. Retotal, round-off and make a side-by-side report.
Learn to convert a glossy glaze into a matte by comparing its chemistry with a target matte formula. Alter the chemistry in such a way that the thermal expansion does not rise and it maintains good physical application and suspension properties.
Learn what crazing is, how it is related to glaze chemistry, how INSIGHT calculates thermal expansion and how to substitute high expansion oxides (e.g. Na2O, K2O) with lower expansion ones (e.g. MgO, Li2O, B2O3).
Shows four different ways to add materials to the desktop Insight materials database (MDT)
Do this completely outside of Insight, it knows how to read it at each startup.
There are five ways to do it. Generate your MDT at digitalfire.com, copy and paste XML, type in the formula, enter an analysis as a recipe, handle the MDT as a CSV file in Excel.
Wollastonite is 50:50 CaO:SiO2. So why not just substitute 40 wollastonite for 20 calcium carbonate and 20 silica?
Learn to substitute Nepheline Syenite for Soda Feldspar (and vice versa) using the KNaO checkbox to. You will see the benefit of in-recipe substitution calculation rather than making substitution rules.
Learn the chemistry differences between cone 10 and 6 glazes and how to make a glaze melt at a lower temperature without introducing other problems like crazing.
How to use desktop Insight to substitute wollastonite for calcium carbonate (and vice versa) while maintaining the same SiO2 level. Create substitution rules.
Use Desktop Insight to explore ways of calculating substitutes for Gerstley Borate in the popular Floating Blue cone 6 glaze recipe while maintaining or improving the other raw and fired properties of the glaze.
How to fine-tune the thixotropy of a ceramic engobe for pottery
Tony Hansen takes you through all the steps from opening the box and wedging the clay to taking the fired mug from the kiln.
*Youtube Video, +MP4 Video, #ScreenCast, ^URL
Fixing a Settling Glaze Slurry
Learn to reformulate a glaze that is settling in the bucket. Al2O3 and KNaO are sourced by the feldspar, we will source them from kaolin and frits instead.
D. Desktop Insight
Click here to watch this at youtube.com or click here to go to our Youtube channel
Change the recipe of a glaze to increase its clay content (and thereby improve its suspending properties) while maintaining the same chemistry (and therefore fired results).
Welcome. In this lesson we are going to fix a problem with a settling glaze.
And if you are not sure of what that is, it refers to: A ceramic glaze that does not stay in suspension, it settles out in the bucket and it is very difficult to stir it back up.
Here is the glaze that I have been supplied.
I am going to copy it, then go into Insight, choose Interpret Clipboard from the menus and click OK.
A ceramic glaze is not a solution, it is a suspension. Simplistically, it is a bunch of rock powder stirred up in water.
Normally that powder should sink to the bottom immediately after you stop stirring.
But the clay in the mix holds all the other powders in suspension.
But at least 15% kaolin or 10% ball clay is needed for this to work.
This glaze has 2.5% bentonite, but no other clays. It needs kaolin.
Before continuing, notice that line containing the frit.
Insight has put an asterisk in front of it to signal us that it could not find this in the materials database.
To figure out what this frit is we will go to the Digitalfire Reference Library and search for it...
Notice it says it is a low alumina, high CaO boro-silicate frit.
At the bottom it links to Ferro Frit 3134 as an alternative.
So in Insight I will click the frit line and enter 3134 in the Materials List Lookup blank and click Update.
Notice that Insight has left the line label as frit 4108, but it is looking up the chemistry of frit 3134 to do the calculation of the chemistry.
How do we proceed?
In the other lessons we learned the best way is to copy it right to recipe 2, we can alter that and compare with the original on the left.
However in this case I tried that and it does not work!
The reason is that there is not very much Al2O3 in the glaze.
I will demonstrate that by opening a target formula for cone 6 to compare.
0.25 is the minimum and we have 0.23.
If I click the Supply button above the formula list, it will show me which material in the recipe is supplying the most Al2O3, it is soda feldspar.
The potash feldspar is going to be contributing a similar amount as well.
There will be almost no alumina coming from any of these other materials.
I will double-click the frit, it has zero alumnia, so the feldspars are the only two materials supplying alumina.
I am going to have to pretty well completely remove those two feldspars and start from scratch in supplying the boron from another frit that has alumina and the boron we need.
I will click recipe 2 and choose a calculation type of no-unity.
Whenever we build from scratch using the supply button we do this.
To start I have the frit 4108 line selected and I want to source boron from it. So I will click the Supply button.
I will check boron and then click Done. This matches up the B2O3.
It has supplied some of the KNaO that I needed (notice I have KNaO checked so Insight combines K2O and Na2O).
I am not going to be able to supply them individually and match them up, but as a total I can.
To supply KNaO I am going to introduce another frit. But which one.
I want one that has alot of K2O and Na2O but very little boron or alumina.
I will click the MDT button to see the materials database.
In frit 3110 we find almost no Al2O3 and a tiny amount of boron.
Notice it has lots of sodium and potassium as well.
I will close this dialog, select a blank line at the end of the recipe and enter frit 3110 in the Materials Lookup field and click Update.
I will click the Supply button. I cannot check the box for K2O and Na2O, but I will check just Na2O.
Notice I have 0.24 KNaO but I need 0.32. So I will increment the frit amount in the recipe and watch it until I get to 0.32.
Notice that in supplying the KNaO I have overshot the B2O3.
I will have to juggle the amount of these two frits, reducing the other and increasing this until I get a match.
I am not being really precise right now, an approximate match is sufficient.
Now I will supply the amount remaining for the CaO, I already have 0.27.
I will check the whiting line and then use the Supply dialog to source it.
I will supply the BaO from Barium Carbonate.
The only ones left to match are alumina and silica.
The alumina is very low, I will be able to supply all of that from Kaolin.
I will add EPK to the recipe, my experience is that it suspends glazes well.
In the supply dialog I will choose Al2O3 and click done.
To match the SiO2 I will choose Silica in the recipe and do likewise.
All the oxides now match.
Because I have been working in no-unity calculation type it totals more than 300.
I will retotal it to 100. The old recipe totalled 102.5 because of the 2.5 added bentonite, I am not using it here.
Notice also that in the old recipe there was copper carbonate and tin oxide.
I have ignored those, I just want to match the base glaze, they can be added later.
I will retotal it now using the ReTotal item in the menu.
Notice that I have 16 parts kaolin, that should suspend the glaze well.
If more suspending power is needed, some of that bentonite could be added back in.
Now notice that the numbers no longer match in the formula. Why?
If I set the calculation type back to RO Unity, they will again match.
Most people do not think chemistry impacts the raw properties of the glaze, the way the glaze slurry works, for example.
But we have created a different set of materials to source the same chemistry, and that set of materials has physical properties that are better.
Also, normally when we do major surgery like this it is to good to see if there are any other problems that could be resolved at the same time.
For example, barium carbonate powder is not the safest thing to use.
If you could find a barium sourcing frit that also had low alumina, you could work it into this recipe also.
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