Lili Krakowski on wed 25 jan 12
Phyllis asks:
" Can soda feldspar be used interchangeably in glazes? Have a recipe for
Albany Slip substitute which lists soda feldspar but I would like to =3D
use
Neph Sy instead (because I have a lot of it). Any downside?"
Dear , sweet Phyllis: when you find ANYTHING in life that has no =3D
downside, please call me collect, anytime, anyplace, anyhow.
Ok. Can Neph Sy be used as a substitute for soda spar (you do not say =
=3D
which) just like that, out of clear blue sky.
Answer: not really. One would need the whole recipe of your Albany Slip =3D
substitute to recalculate the whole glaze. =3D20
All the following by GlazeMaster (TM)
Analysis of Kona 4
.578 Na2O
.265 K2O
.157 CaO
.998 Al2O3
5.773 SiO2
And NC 4
.618 Na2O
.222 K2O
.001 MgO
.159 CaO
1.022 Al2O3
.002 Fe2O3
6.37 SiO2
And Norfloat
.667 Na2O
.167 K2O
.166 CaO
1.022 Al2O3
.003 Fe2O3
6.311 SiO2
And good old generic Neph Sy.
"Generic" because Neph Sy comes from several sources, not consistent.
Like all our mined materials, formula not written in stone (Sound of =3D
laughter--I hope)
.712 Na2O
.22 K2O
.011 MgO
.056 CaO
1.03 Al2O3
.002 Fe2O3
4.555 SiO2
So Neph Sy has less silica, but you certainly can test. And as you see =3D
you can adjust the alumina to taste.=3D20
As to your Albany Slip Substitute.
Here are two recipes of mine, (PMI Summer 2000) you might give a try. =3D
Both spar and nephsy free:
ALBANY SLIP SUBSTITUTE I for recipes that call for added iron:
RedArt 84.7
Dolomite 11.7
Wollastonite 3.6
ALBANY SLIP SUBSTITUTE II for recipes that call for Albany slip
but have no extra iron added:
RedArt 66.7
Kentucky Ball Clay 16.7
Dolomite 8.3
Wollastonite 8.3
I wet mix and sieve these several times, dry out thoroughly and use as =3D
direct substitution in recipes.
Lili Krakowski
Be of good courage
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