Tony Hansen's Thousand-Post TimeLineI am the creator of Digitalfire Insight, the Digitalfire Reference Database and Insight-live.com. ... more 
A flameware recipe. Are they kidding?
This is a flameware, made from a recipe promoted by a popular website. Are they serious? How could you throw this? Maybe it is possible, but we need an explanation. How could the page fail to mention how coarse this surface would be? How porous and weak ware would be? We find many body and glaze
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Context: Grog, Flameware, Ovenware, Glaze Recipes Tuesday 17th October 2017 
The high thermal expansion of a low-fire talc body
Talc is employed in low fire bodies to raise their thermal expansion (to put the squeeze on glazes to prevent crazing). These dilatometer curves make it very clear just how effective that strategy is! The talc body was fired at cone 04, the stoneware at cone 6. The former is porous and completely
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Context: Talc, G1916Q - Low Fire Frit 3195 Glossy Transparent, Low Fire White Talc Casting Body Recipe, Calculated Thermal Expansion, Co-efficient of Thermal Expansion, Shivering Wednesday 11th October 2017 
Three low fire bodies need three different clear glazes. Why?
Glaze fit. The left-most clay mug contains no talc (Plainsman Buffstone), the centre one about 25% talc (L212) and the right one is about 45% talc (L213). Talc raises thermal expansion. The centre glaze is G2931K, it is middle-of-the-road thermal expansion (Insight-live reports it as 7.4) and fits
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Context: G2931H - Ulexite High Expansion Zero3 Clear Glaze, G2931L - Low Expansion Low-Fire Clear, G2931K - Low Fire Fritted Zero3 Transparent Glaze, Transparent Glazes, Glaze fit, Cone 03 Drop-and-Hold Sunday 8th October 2017 
Plucking on a vitreous porcelain at cone 6
The mug on the left is made from a whiteware body (Plainsman M370), the one on the right is a highly vitreous translucent one (Plainsman Polar Ice). Both have been over-fired slightly. The Polar Ice mug has stuck to the shelf somewhat, taking chips out of the base on the outer perimeter of the bare
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Context: The foot ring on the left is plucking, the right one is not. Why?, Plucking Wednesday 4th October 2017 
The foot ring on the left is plucking, the right one is not. Why?
These are translucent porcelains, they are vitreous. The firing is to cone 10. The one on the left is a cone 6 body, and, while it survives to cone 10 it does warp. But more important, it is much more vitreous (more melted). The plucking problem makes it quite difficult to get a good foot ring. The
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Context: Plucking on a vitreous porcelain at cone 6, Kiln Wash, Porcelain, Vitrification, Plucking Wednesday 4th October 2017 
A black engobe transforms the floating blue glaze over it
M340 stoneware fired to cone 6 (drop-and-hold schedule). The L3954B engobe fires deep black (it has 10% Mason 6600 black stain instead of the normal 10% Zircopax). It was applied inside and partway down the outside (a much less messy process than using a black clay body). They were bisque fired and
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Context: L3954B - White Cone 6 Engobe for Plainsman M390, M340, Cone 6 Drop-and-Soak Firing Schedule Monday 2nd October 2017 
Dark Umber-Stained Engobes on M340 at cone 6
This is the standard Plainsman L3954D white engobe recipe with the 10% Zircopax switched for Burnt Umber. The result is a dark, rich, ultra-gloss brown (almost black). The engobe is applied inside and half-way down the outside. The mug on the left is glazed inside and out with the base GA6A Alberta
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Context: L3954B - White Cone 6 Engobe for Plainsman M390, M340, GA6-A - Alberta Slip Cone 6 Amber Base Glaze Monday 2nd October 2017 
Measuring glaze slurry specific gravity
This is the easiest way to measure the specific gravity of a glaze if it is not in a container deep enough to float a hydrometer (or if it is too thick to float it properly). Just counterbalance the empty graduated cylinder to zero, fill it to the 100cc mark and the scale reads the specific gravity.
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Context: Understanding the Deflocculation Process in Slip Casting, Specific gravity of a glaze using a scale and measuring cup, Deflocculation, Specific gravity, Rheology, Thixotropy Friday 22nd September 2017 
6% rutile is too much in this cone 6 oxidation glaze
Rutile variegates glaze surfaces. But it also opacifies at higher percentages. The blue effect is a product of crystallization that occurs during cooling, it is thus dependent on a slower cooling cycle, especially above 1400C. This is GA6-C Alberta Slip glaze with 4, 5 and 6% rutile. At 6% the
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Context: Ceramic Rutile, Rutile, Cone 6 rutile floating blue effect lost. Then regained., Cone 6 Drop-and-Soak Firing Schedule, Rutile Glaze Thursday 21st September 2017 
How to convert a dipping glaze to a brusing glaze
I have a jar of clear glaze that I mixed myself (it has 10% yellow stain and 2% zircopax added). The cost of the dry materials: About $6. How can I convert it to a paintable glaze like the commercial ones I buy for $20 a jar? I made a spreadsheet to do it for me. It knows the weight of the plastic
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Context: CMC Gum, Where Do I Start?, Brushing Glazes Wednesday 20th September 2017 |
Login to your online account Chemistry plus physics. The on-line successor to desktop Insight. Get an account for as little as $15. It does so much more. 
Still available for Mac, PC, Linux Interactive glaze chemistry calculations. How to reach usFrom within your account at Insight-Live.com or
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