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more about publishing vs. bosom-clutched glze recipes.

updated fri 20 may 11

 

Lili Krakowski on thu 19 may 11


During the most recent Publishing Recipes go-around, I wrote that many =3D
a Top Secret Glaze has escaped into the Free Glaze Zone through. =3D
recalculation.=3D20


I promised/threatened a follow up that should convince One-and-All of =3D
the indispensability of glaze calculation.




Here is my electric fired, c.6, C11 glaze. It is semi-transparent, silky =
=3D
white when opacified. It works well with colorants, especially those =3D
that benefit from high magnesium.



All calculations by GlazeMaster (TM)


C11




Frit 3195 27.50

Dolomite 24.56

Clay 20.43

Silica 27.50=3D20




.077 Na2O

.003 K2O

.352 MgO

.568 CaO




.298 Al2O3

.255 B2O3







2.222 SiO2













As you guessed, it can be made up by volume, using same measure for =3D
each ingredient.




Well, something goes wrong. A drip in the roof reduced a five pound bag =3D
of F 3195 into a mudpuddle. A rodent destroyed the plastic container of =3D
dolomite...Do not worry....these and more disasters have happened in my =3D
glaze pantry.




You dash frantically to your glaze program...or your calculator,, =3D
pencil, and charts. And produce:






Helter Skelter





29.5 Frit--Ferro 3124

17.2 Talc

8.4 Whiting

27.1 Ball Clay--Old Mine #4

8.4 Flint

9.5 Laguna Borate




100.1 Total




.095 Na2O

.016 K2O

.34 MgO

.549 CaO




.276 Al2O3

.238 B2O3




2.091 SiO2




That works, and you go with that for a few years, when miraculously, =3D
you are transported to a British studio, with its "foreign"materials;




And you get




Corgi Bliss




15.7 Frit--CTM Calcium Borate

18.5 Talc

7.8 Whiting

13 Kaolin--Grolleg

21.9 Flint

23 Neph Sy--Podmore










.07 Na2O

.065 K2O

.36 MgO

.505 CaO




.288 Al2O3

.293 B2O3

.002 Fe2O3


2.271 SiO2







See what I mean? I could have clutched C11 to my bosom forever, and it =3D
still could have "gotten out there" in disguise. Or why I do not believe =
=3D
in bosom-clutching glazes. Besides which age does enough damage to =3D
the bosom without help from glaze-clutching!




As I am devoted to high magnesium glazes, I have a stash of high MgO =3D
recipes. And while some are lovelier than others on the clay body I =3D
currently use , the variations are small. The actual changes that come =3D
from new batches of "same label" materials add to the confusion.




Changes in glaze recipes may come about from their modification for =3D
different clay bodies. The "basic" recipe is changed, and transmitted in =
=3D
revised form.




This is why I believe in speaking of glaze "families'. C11 is a high =3D
magnesium calcium borate glaze.=3D20







Lili Krakowski
Be of good courage