Category: Glaze > Blue
Created 2015-10-21 00:41:06 by Terry Rorison
Categories: Glaze > Blue
Firing Temperature: Δ6
Atmospheres: Oxidation
Surface Type: Glossy
Transparency: Transparent

"I have introduced a cooling cycle to the firing. The cycle is as follows and the firing is accompanied by a Cone 6 witness cone. After 12 consecutive firings, the witness cones are identical from firing to firing."

The firing cycle:
Rate Temp Hold Time
rA1= 360 F1 = 900 0
rA2= 300 F2 = 1800 0
rA3 =200 F3 = 2016 0
rA4 = 108 F4 = 2197 0.3
rA5 = Full F5 =1800 0
rA6 =150 F6 = 1300 0
rA7 = 0000

To summarize, I fire at a rate of 360/hr to 900 degrees F, then at 300 degrees/ hr to 1800 degrees F, 200 degrees/hr until 2016 degrees F is reached, then 108 degrees/hour to 2197 at which time I hold it at that temperature for 30 minutes.

The kiln is shut off until a temperature of 1800 degrees F is reached and then turned on to slow the rate of cooling to 150 degrees/hr until 1300 degrees F is reached. At this point the kiln is turned off and cools naturally.

Western Pennsylvania Potters Community

Material Amount Batch Subtotal
Minspar 200 46.2
Silica 16.5
Whiting 14.3
Frit 3134 13.3
EPK 6.4
Talc (Theoretical) 3.3
Total Base:100
Zinc Oxide 4.4
Tin Oxide 2.4
Bentonite 2
Copper Oxide 1.1
Total: 109.9

Percentage Analysis

Ingredient Amount SiO2 Al2O3 B2O3 MgO CaO ZnO K2O Na2O KNaO P2O5 Fe2O3 TiO2 CuO SnO2 LOI
Minspar 20046.231.838.580.
Frit 313413.
Talc (Theoretical)
Zinc Oxide4.44.4
Tin Oxide2.42.4
Copper Oxide1.11.1
100% no LOI 59.4311.143.011.0811.184.311.94.356.

Unity Molecular Formula (UMF)



0.19 Na2O
0.05 K2O
0.14 ZnO
0.54 CaO
0.07 MgO


0.3 Al2O3
0.12 B2O3


2.68 SiO2
0.04 SnO2


0.04 CuO





0.24 : 0.76

SiO2:Al2O3 Chart

Closest 100 neighbors in Glaze > Blue.

Click and drag to zoom
Stull Chart
SiO2:Al2O3 Ratio
SiO2:Al2O3 Ratio 9.06

Similar Base Recipes

Similar RO/R2O Unity Formulas

Recipe Name ΔTemp Al2O3 B2O3 SiO2 ZrO2 SnO2 TiO2 KNaO K2O Na2O CaO MgO ZnO BaO PbO Li2O SrO
Blue Green Sugar Maples 6 0.3 0.12 2.68 0.04 0.24 0.05 0.19 0.54 0.07 0.14
Blue Green Copper Red Glaze 6 0.27 0.12 2.69 0.04 0.25 0.13 0.12 0.53 0.07 0.15

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09/2016 Note: This is a new feature. If a recipe material is not listed, that material's data has not yet been added. Some materials only have GHS ratings, while others only have HMIS ratings. Warnings differ between systems and countries. Glazy does not take any responsibility for accuracy of linked SDS information. Contact your ceramics supplier for safety information for your specific materials.
Globally Harmonized System (GHS) Hazardous Materials Identification System (HMIS) SDS Link
Material Pictograms Signal Word Hazard Statements Health Flammability Hazard Protection
Minspar 200 Health Hazard WARNING May cause damage to lung through prolonged or repeated inhalation 2 0 0 E
Silica HarmfulHealth Hazard DANGER From 200-Mesh SDS:
May cause cancer by inhalation.
Causes damage to lungs through prolonged or repeated exposure by inhalation.
* 0 0 E
Whiting Harmful WARNING Causes eye irritation
EPK HarmfulHealth Hazard DANGER EPK Kaolin is a naturally occurring mineral, which may contain amounts of crystalline silica
typically 0.1-1.0%, may cause damage to respiratory system through prolonged or repeated
1 0 0 E
Talc (Theoretical) Harmful WARNING Causes mild skin irritation
Harmful if inhaled
May cause respiratory irritation
1 0 0 E
Zinc Oxide 0 0 0 *
Tin Oxide Harmful WARNING Harmful if swallowed.
Bentonite Harmful WARNING Causes eye irritation
Causes skin irritation
May cause respiratory irritation
Copper Oxide Harmful WARNING Harmful if swallowed 2 0 0 E