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my copper has gas

updated mon 25 jan 10


lili krakowski on sun 24 jan 10

As I know nothing about computerized kilns etc I can only suggest you =3D
lower the alumina content of the glaze.

Copper =
per(says =3D
Fournier) tends to volatilize. He also say copper carb will decompose in =
hot water...just a minimal point in case you mix your glazes in hot =3D
water--and I have no idea what the decomposition would lead to.

Cooper ("Electric Kiln Pottery") says that copper starts to volatilize =3D
at around 1922 F (around c.04) and I have no idea whether your cooling =3D
cycle can affect that...

Calculations by GlazeMasterT

Your glaze:

.153 Na2O
.015 K2O
.006 MgO
.826 CaO
1.000 Total
.304 Al2O3
.266 B2O3
.004 Fe2O3

3.363 SiO2

So, following instinct (duh!)

21 Whiting
28.7 Frit--Ferro 3195
16.6 Kaolin--EPK
9.5 Frit--Ferro 3110
24.1 Silica

.158 Na2O
.009 K2O
.008 MgO
.825 CaO
1.000 Total

.297 Al2O3
.303 B2O3
.003 Fe2O3

2.612 SiO2

I would expect the lowering of Alumina and raising of B203 to help =3D
matters. If it crazes you can try calcined kaolin and some 2-3% =3D

Lettuce know.

Lili Krakowski
Be of good courage