Lili Krakowski on wed 20 apr 11
My first suggestion, always and ever, for any glaze problem is: PANIC. =3D
Give yourself a full minute for this, then make a nice cup of tea and =3D
consider.
(A problem here: RonJohn do not want us to publish their recipes. I =3D
hope that molecular formula will be ok)
The proper formula is low in alkalis--they total .103--high in CaO, with =
=3D
high Alumina and Silica, and mid-range-for-this-temp B203.
To my amusement the COE is a tidge below the minimum RonJohn consider =3D
desirable. And what is stranger is that the formula I got with Glaze =3D
Master T differs slightly from that given in the book.=3D20
Having fed the recipe into Glaze Master T , I changed the nephsy content =
=3D
to 4 times what it is supposed to be!
Your error "replaced" calcium with alkalis, raising them from .103 to =3D
.171, lowered the B2O3 a bit, and raised alumina and silica.=3D20
Will the replacement of calcium with more active fluxes make up for the =3D
increase in alumina? In a glaze that already is high in it?=3D20
I do not know.but I think you should mix that mess up, into a glaze and =3D
test. The glaze might work fine, though I would expect it to be matter =3D
than the original intention.=3D20
If it is too matt for your taste. Take out about two measuring cups of =3D
it, and dry them thoroughly. As the stuff dries, crumble it up, because =3D
often glaze does not dry totally unless one does.
Weigh out 100 gram batches and test with 3%, 5%, 6%, 10% Frit 3134. My =3D
guess is that IF the glaze turned out too matt to begin with, you will =3D
find a workable finish this way. And you may have to "redo" at the =3D
in-between percentages.
And, next time, do yourself a favor. When measuring out glaze, weigh out =
=3D
each material, put in marked plastic bag. (The cheapest, thinnest are =3D
best) Then, before you pour the ingredients into the bucket, weigh each=3D2=
0
Lili Krakowski
Be of good courage
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