Category: Glaze > Iron
Created 2017-07-24 14:07:16 by Jayne Bunting
Categories: Glaze > Iron
Firing Temperature: Δ5-6
Atmospheres: Neutral
Surface Type: Satin - Matte
Transparency: Opaque

Vinod Chettur revision from a classic glaze (VC mate 71). Brown yellowish, breaks brown. Satin matte.
I use to fire it at a hot cone 5, with slow cooling cycle: 2 hours from peak temperature to 850°Celcius.

Jayne Bunting:
I replaced the Frit 3134 originally in this recipe for Gillespie Borate 9 I don't know if it were due to this or the firing which was
to Cone 6, 20 min hold (no slow cool) that my results were nothing like those pictured in the original recipe (Photo FIG 1). I will attempt the recipe again like for like and see if I get my matte iron yellow! However.........

I did try the base recipe (FIG 2 BASE) on clay body B = Scarva Earthstone Porcelain White and C = Oxidising St Thomas Stoneware

with the following Variations

R7102 + Copper Carbonate 5 (FIG 3)

R7103 + Rutile 15 (FIG 4)

I then achieved some lovely results from layering one colour variation over another (1 short dip for each layer)

(FIG 5) is the R7101 with R7103 over
(FIG 6 ) is the R7102 with R7105 over
(FIG 7 ) is the R7101 with R7102 over

Material Amount Batch Subtotal
Potash Feldspar (Theoretical) 36
Silica 17
Whiting 15
EPK 14
Gillespie Borate 9
Talc (Theoretical) 9
Total Base:100
Red iron oxide 6
Copper Oxide 2
Total: 108

Percentage Analysis

Ingredient Amount SiO2 Al2O3 B2O3 MgO CaO SrO K2O Na2O KNaO P2O5 Fe2O3 TiO2 CuO LOI
Potash Feldspar (Theoretical)3623.316.66.096.09
Gillespie Borate91.
Talc (Theoretical)95.72.870.43
Red iron oxide65.70.3
Copper Oxide22
100% no LOI 55.8112.52.33.3710.970.046.410.366.770.

Unity Molecular Formula (UMF)



0.02 Na2O
0.19 K2O
0.55 CaO
0.24 MgO


0.35 Al2O3
0.09 B2O3


2.63 SiO2


0.11 Fe2O3
0.07 CuO





0.21 : 0.79

SiO2:Al2O3 Chart

Closest 100 neighbors in Glaze > Iron.

Click and drag to zoom
Stull Chart
SiO2:Al2O3 Ratio
SiO2:Al2O3 Ratio 7.58

Similar Base Recipes

No recipes with similar base ingredients and amounts were found.

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No recipes with similar RO/R2O Unity Formulas were found.

Clara Giorello 2017-07-26 15:02:40
Hi Jayne. Glad to see all your testing. Nice results. Try slow cooling to get the iron yellow. All my materials are local (Argentina), so it is almost impossible to replicate. I found the Vinod Chettur variation in a long thread about VC71 in Ceramic Recipes. He suggested this variation to perform a better melt.


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
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
Red iron oxide Health Hazard WARNING May cause damage to lung through prolonged or repeated exposure by inhalation
Copper Oxide Harmful WARNING Harmful if swallowed 2 0 0 E