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!
Insight-live shows recipes in tall narrow panels. They open side-by-side right-ward. They remember the type of calculation last requested. So just opening multiple recipes automatically enables comparison.
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 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.
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.
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
Formulating Substitution Rules for Calcium Carbonate and Wollastonite
How to use desktop Insight to substitute wollastonite for calcium carbonate (and vice versa) while maintaining the same SiO2 level. Create substitution rules.
D. Desktop Insight
Click here to watch this at youtube.com or click here to go to our Youtube channel
How to use Digitalfire Insight software to determine how much wollastonite to substitute for whiting to maintain the same SiO2 in the glaze. Covers rationalization of the relative merits of materials, using the Supply Oxide dialog both ways on side-by-side no-unity recipes, and learning to spot obvious supply problems and theoretical vs. actual materials.
Welcome. In this lesson I am going to talk about formulating material substitution rules, I will use calcium carbonate and wollastonite as an example.
We will be discussing rationalization of the relative merits of materials, using the Supply Oxide dialog both ways on side-by-side no-unity recipes, and learning to spot obvious supply problems and theoretical vs. actual materials.
Comparing these materials
As you might know, wollastonite and whiting (or calcium carbonate) are two common sources of CaO used in glazes. You can find out more about them the Digitalfire Reference Database.
Theoretically, whiting is a mix of CaO and CO2 gas, it has a high LOI and is inexpensive and potentially inconsistent, wollastonite is a mix of CaO and SiO2, has no LOI and is more expensive and more consistent.
How to substitute for wollastonite?
Suppose you are asked what proportion of whiting and silica should be put into a glaze to substitute for a wollastonite amount of 30 (we will consider a whiting-to-wollastonite switch in a moment). This problem is different than described in the previous lesson because you have not been given the recipe. There are some mistakes that are very easy to make here so let us go through it and see.
Add silica & fine tune its amount
I have set both recipes to RO Unity.
And entered 30 wollastonite for recipe 1 line 1.
And switched to recipe 2 and entered 15 whiting in line 2 and 15 silica in line 3 (I am guessing on the amounts).
INSIGHT calculates this formula.
Now I am going to click the decrement button until the SiO2 figures in the formula match. That happens at 9 parts silica in the recipe.
Problem: Set to no unity
Take a closer look.
This cannot be right because whiting has a high LOI (it loses weight during firing as some of it turns to gas) so the combination of silica and whiting raw powder must total more than the amount of wollastonite. The problem is that I should be calculating with a No Unity setting for recipe 2 so that the whiting/silica formula represents the actual weight of material needed, not the relative numbers of molecules. I will do that now.
Match the no unity formula
I have just increased the whiting and silica weights until both the CaO and SiO2 numbers in the formula match.
But this cannot be right either, how could 160 parts of whiting:silica be needed to substitute for just 30 wollastonite?
What is the problem? Recipe 1 is still set at RO Unity. Remember, unifying a recipe means that changing the total of a recipe has no effect on the calculated formula, it is always unified. But I need the formula to be sensitive to the weight I specify.
I will set recipe 1 at No Unity calculation.
Use the supply button
Although I could move the amounts of whiting and silica up and down using the increment and decrement arrows, there is an easier way.
I will select recipe 2 and click the whiting line. I will click the Supply button to tell INSIGHT how much CaO I want from whiting. The supply dialog defaults the number of CaO oxide molecules being sought to the number in the other recipe.
I will click Done.
Select the silica line for recipe 2 and click the Supply button and do the same.
That looks better, now we have a match. It takes 25.8 grams of whiting and 15.51 of silica to substitute for 30 of wollastonite.
Formulating a substitution rule
Suppose I wanted to come up with a general guide line such as "for each gram of wollastonite substitute x grams of whiting and y grams of silica". I have just done it.
I selected recipe 1 and changed the amount of wollastonite to 100
Then selected recipe 2 and used the Supply button to resupply the whiting and silica.
Now I can say: For each 100 grams of wollastonite substitute 86.1 grams of whiting and 51.7 grams of silica, or for each 1 gram substitute 0.86 grams of whiting and 0.517 grams of silica.
Inversing the rule
Now, let’s invert that rule. I have changed the amount of whiting to 100 in recipe 2, selected recipe 1 line 1 and used the Supply button to source CaO from Wollastonite.
Then I selected recipe 2 line 3 and supplied SiO2 from silica.
The formulas now look like this.
So the rule now is: For each 100 grams of whiting substitute 116.2 of wollastonite and remove 60.1 of silica. For each one gram whiting I would add 1.162 of wollastonite and remove 0.601 of silica.
What was the magic?
The magic behind this two-way calculation technique is INSIGHT's dual recipes, its ability to calculate with no unity, its Supply Oxide dialog, and the fact that each recipe is a fully functioning entity.
In conclusion I want to remind you that we have been talking about theoretical calcium carbonate and wollastonite, for two real-world materials with contaminating oxides it would be more complicated. But this general rule should still be sufficient for most situations.
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