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.
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.
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
Thixotropy and How to Gel a Ceramic Glaze
I will show you why thixotropy is so important. Glazes that you have never been able to suspend or apply evenly will work beautifully.
Click here to watch this at youtube.com or click here to go to our Youtube channel
I will establish specific gravity first, then gel the slurry, then establish thixotropy. This will change your life! Glazes that you have never been able to suspend or apply evenly will work beautifully. Visit the links you see on this page to learn more. Understand the difference between specific gravity, viscosity and thixotropy. You will not believe what you see and how valuable this knowledge is!
The main question I get is how does one know what specific gravity to target for potters who are glazing bisque ware? Generally, start like this: Raw glaze (no frits) around 1.42. Partly fritted around 1.45. Alot of frit around 1.48. This should produce a slurry that is quite runny and ready to accept vinegar. Add it until you stir, stop and it continues in motion for 2 seconds and stops. If it is not runny then do not add any vinegar yet. Now put your hand or some other stirring implement into the slurry and extract it. When you do so the glaze should gel and hang on, covering it completely evenly. Only a couple of drips show fall off it. If it is not doing this, and the slurry is already viscous, you need to add water to enable gelling with vinegar. When it is right it should stop and bounce back slightly after two seconds. Repeat the process as needed. Be careful about how much vinegar you add so you do not turn it into jello. I like to have the specific gravity such that 3-4 capfuls of vinegar gels a gallon. If the slurry is too responsive to the vinegar, then the specific gravity is too high.
One more thing to keep in mind. I am talking about glazes that have enough clay in them to harden them well and suspend well. That means 15-25% kaolin or 10-20% ball clay. If your glaze has very little clay or it has a ton of clay, then you have a special case. This gelling process may still work, but it is better to reformulate the glaze, using glaze chemistry so it has the right amount of clay (there are videos and articles here on doing that). Gerstley Borate is a special case, it has the power of ball clay to suspend. If the glaze also contains clay in addition to the GB, then it is too high in plastic materials. GB gels glazes and turns them in a mess if there is 30% or more. Forget about using vinegar for these, you are more likely to need to do the opposite, deflocculate them. Seriously consider learning how to substitute the GB for Ulexite or a frit (there are videos and articles here on doing that too).
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