Category: Glaze > Blue
Created 2015-10-21 00:56:09 by Terry Rorison
Categories: Glaze > Blue
Firing Temperature: Δ6
Atmospheres: Oxidation
Surface Type: Satin
Transparency: Opaque

"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
Nepheline Syenite (Theoretical) 52.8
Strontium Carbonate 30.2
EPK 8.5
Silica 6.6
Whiting 1.9
Total Base:100
Copper Carbonate 4.3
Bentonite 3
Total: 107.3

Percentage Analysis

Ingredient Amount SiO2 Al2O3 MgO CaO SrO K2O Na2O KNaO P2O5 Fe2O3 TiO2 CuO LOI
Nepheline Syenite (Theoretical)52.832.0512.30.050.372.435.
Strontium Carbonate30.221.29
Copper Carbonate4.32.771.53
100% no LOI 47.1417.110.131.5822.552.655.618.

Unity Molecular Formula (UMF)



0.25 Na2O
0.08 K2O
0.59 SrO
0.08 CaO
0.01 MgO


0.46 Al2O3


2.13 SiO2


0.1 CuO





0.32 : 0.68

SiO2:Al2O3 Chart

Closest 100 neighbors in Glaze > Blue.

Click and drag to zoom
Stull Chart
SiO2:Al2O3 Ratio
SiO2:Al2O3 Ratio 4.68

Similar Base Recipes

Δ5 - 6

Similar RO/R2O Unity Formulas

Recipe Name ΔTemp Al2O3 B2O3 SiO2 ZrO2 SnO2 TiO2 KNaO K2O Na2O CaO MgO ZnO BaO PbO Li2O SrO
Carmen's Turquoise 6 0.46 2.13 0.33 0.08 0.25 0.08 0.01 0.59
Carmen's Turquoise (tom's add more clay variation) 6-7 0.44 2.1 0.01 0.33 0.08 0.25 0.08 0.01 0.58

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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
Strontium Carbonate Harmful WARNING Product dust may be irritating to eyes,skin and respiratory system.  1 0 0 E
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
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
Copper Carbonate Harmful WARNING Harmful if swallowed.
Causes skin irritation.
Causes serious eye irritation.
Bentonite Harmful WARNING Causes eye irritation
Causes skin irritation
May cause respiratory irritation