Three Glazes

The glaze half way between iron_8_11 and iron_8_Right, named iron_8_13 for its position in the line blend from which all these glazes are derived shivers as shown in the last picture.

The two end glazes, iron_8_11 and iron_8_Right have now been fired several times, show no glaze fit problems. Wherefore is this glaze "in the middle" different? I will be gratefull if any of you have suggestions.

glaze iron_8_11 plate ~8.5 inch diameter

glaze iron_8_Right plate ~ 8.5 inch diameter

glaze iron_8_11 + iron_8_Right bowl ~ 5 inch diameter

glaze iron_8_11 + iron_8_Right showing shivering on outside of bowl

The glaze iron_8_Right + iron_8_Right is iron_8_13, the midpoints between the two glazes.

The recipes and empirical formulas of the three glazes

iron_8_11 Recipe

Ball_Clay	28
Bentonite	6
Bone_Ash	8
Frit_413	42
G_200_HP_Feldspar	44
Lithium_Carbonate	12
Magnesium_Carbonate	8
Nepheline_Syenite	30
Red_Iron_Oxide	18
Silica	4

iron_8_11 Empirical Formula

K2O 0.1289	Al2O3 0.4200	SiO2 2.7689
Na2O 0.2866	B2O3 0.0000	P2O5 0.0387
Li2O 0.2634	Fe2O3 0.1889	ZrO2 0.0000
CaO 0.1483		TiO2 0.0068
MgO 0.1728		SnO2 0.0000
SrO 0.0000
ZnO 0.0000
BaO 0.0000

iron_8_Right Recipe

Bentonite	6
Bone_Ash	8
Dolomite	4
Frit_413	42
G_200_HP_Feldspar	52
Lithium_Carbonate	11
Nepheline_Syenite	58
Red_Iron_Oxide	19

iron_8_Right Empirical Formula

K2O 0.1637	Al2O3 0.4208	SiO2 2.8319
Na2O 0.3578	B2O3 0.0000	P2O5 0.0386
Li2O 0.2403	Fe2O3 0.1954	ZrO2 0.0000
CaO 0.1876		TiO2 0.0000
MgO 0.0506		SnO2 0.0000
SrO 0.0000
ZnO 0.0000
BaO 0.0000

iron_8_13_recipe

Bentonite	6
Bone_Ash	8
Dolomite	4
Frit_413	42
G_200_HP_Feldspar	52
Lithium_Carbonate	11
Nepheline_Syenite	58
Red_Iron_Oxide	19

iron_8_13 Empirical Formula

K2O 0.1463	Al2O3 0.4204	SiO2 2.8004
Na2O 0.3223	B2O3 0.0000	P2O5 0.0386
Li2O 0.2518	Fe2O3 0.1922	ZrO2 0.0000
CaO 0.1680		TiO2 0.0034
MgO 0.1116		SnO2 0.0000
SrO 0.0000
ZnO 0.0000
BaO 0.0000