Sally Guger on wed 22 aug 07
After all of the hit and miss reading I've done over the past few days, (7000 out of 27,000 emails) I've decided to order the Mastering Cone 6 Glaze book- not from Amazon!!
In the meantime I have a question for Ron Roy or anyone else who knows glazes.
I've used a simple formula on and off for years- adding a wide variation of colorants- in the forms of oxides and carbonates- how do I know if this glaze is stable or not?
It is:
Flint 20
Wollastonite 20
Gertsley Borate 20
Ball Clay 20
Neph. Sye 20
It seems too easy- but always behaves at cone 4-6- doesn't run, craze, or pinhole. I have about 10 different color variations I use.
For example my texture blue has
Zircopax 10
rutile 2
iron ox. 1
cobalt ox. 2.5
Dark green has
CHROME OXIDE 2.5
COPPER OXIDE 2.5
COBALT OXIDE 0.5
ZIRCOPAX 5.0
It works well on white or dark-colored stoneware in ox. Thanks for the input.
Live, Give, Love
Beyond All Expectation.
Sally Guger
Lakespur Blue Pottery & Sculpture
Lodi, Wisconsin, USA
---------------------------------
Pinpoint customers who are looking for what you sell.
Ron Roy on mon 27 aug 07
Hi Sally,
If it's mixed with the older versions of GB then it looks like a stable
glaze - if you use the currently available GB it may not be - alumina and
silica go up quite a bit.
With the old GB the blue looks good - rutile is helpful when stability is
required. The green has a lot of colouring oxide - remember - it is hard to
keep a lot of them in solution - especially when copper is involved. You
will need to have it tested to see if you can live with the amount of oxide
release.
I have included a revised recipe using frit 3134 subbed in for the GB - you
will at least know you will get a glaze that is as stable as the original.
I also replaced the Neph Sy which can be problematic. I am assuming you
have Custer. If not tell me what spar you have and I'll do it over.
The expansion is a bit lower but everything else is very close.
Always test a new glaze - say a 500 gram or a 1000 gram batch. I don't keep
copies of glazes I work on by the way so if it needs work send it back with
your request.
Let us know how it compares with the original.
Our web site is www.masteringglazes.com
There is a list of suppliers who sell our book.
CUSTER SPAR......... 13.50
Wollastonite........ 18.50
F3134............... 25.50
TALC................ 3.00
EPK................. 23.50
SILICA.............. 16.00
----------
100.00
FORMULA & ANALYSIS
------------------
*CaO........ .71 13.79%
MnO2....... .00 .01%
*MgO........ .09 1.25%
*K2O........ .05 1.52%
*Na2O....... .15 3.23%
Fe2O3...... .00 .28%
TIO2....... .00 .07%
B2O3....... .26 6.14%
AL2O3...... .34 11.96%
SiO2....... 2.98 61.71%
P2O5....... .00 .03%
RATIO 8.77 (original is 8.67)
EXPAN 435.58 (original is 438.08)
WEIGHT 289.66 (original is 289.35)
RR
>After all of the hit and miss reading I've done over the past few days,
>(7000 out of 27,000 emails) I've decided to order the Mastering Cone 6
>Glaze book- not from Amazon!!
>
> In the meantime I have a question for Ron Roy or anyone else who knows
>glazes.
> I've used a simple formula on and off for years- adding a wide variation
>of colorants- in the forms of oxides and carbonates- how do I know if this
>glaze is stable or not?
> It is:
>
> Flint 20
> Wollastonite 20
> Gertsley Borate 20
> Ball Clay 20
> Neph. Sye 20
>
> It seems too easy- but always behaves at cone 4-6- doesn't run, craze,
>or pinhole. I have about 10 different color variations I use.
>
> For example my texture blue has
> Zircopax 10
> rutile 2
> iron ox. 1
> cobalt ox. 2.5
>
> Dark green has
> CHROME OXIDE 2.5
> COPPER OXIDE 2.5
> COBALT OXIDE 0.5
> ZIRCOPAX 5.0
>
> It works well on white or dark-colored stoneware in ox. Thanks for the input.
>
>
>
>
>
>Live, Give, Love
> Beyond All Expectation.
> Sally Guger
>Lakespur Blue Pottery & Sculpture
>Lodi, Wisconsin, USA
>
>
>---------------------------------
>Pinpoint customers who are looking for what you sell.
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
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>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
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