Paul Raymond on tue 18 nov 03
Did my first glaze firing this weekend and that fact in and of itself is cause for celebration. Finally, 10 or 11 years after seeing my first pot come out of the kiln at Pasadena City College I have my own studio and equipment and I'm off and running.
The glaze I used came from RR and JH's book and is called Glossy Base Glaze 2 on pg 96. I mixed a 2000 gram batch of it and then another batch of the same size with the addition of 5% Sn. The clear was fine; it performed flawlessly. However, the variation with the tin pinholed quite a bit. Any ideas why this occured? I fire in an electric with a down draft venting system and it was a very even firing, my 3 cone packs were all equally bent, none more than another. I got up to temp in about 11 hours and soaked for 20 minutes. Cooled for about 18 hours before unloading. A book or 2 of mine says this may be caused by a immature firing but cone 6 was flat. Are there other possibilites or is SnO a tricky chemical that requires special care, should I have soaked for a longer period?
Also, I would like to thank all of you who take the time to answer my posts. I truly appreciate it. I try to email all af you off line but If I missed anyone, my appologies.
Paul Raymond
Franklin, Tn
Ron Roy on wed 19 nov 03
Hi Paul,
This seems strange - tin is a refractory at cone 6 but 5% should not result
in an underfired glaze. Better repeat the test by remixing a small amount
of the glaze - just to make sure you measured properly.
If the same thing happens let me know and I will reformulate that glaze
with the tin to make it melt more.
RR
>Did my first glaze firing this weekend and that fact in and of itself is
>cause for celebration. Finally, 10 or 11 years after seeing my first pot
>come out of the kiln at Pasadena City College I have my own studio and
>equipment and I'm off and running.
>
>The glaze I used came from RR and JH's book and is called Glossy Base
>Glaze 2 on pg 96. I mixed a 2000 gram batch of it and then another batch
>of the same size with the addition of 5% Sn. The clear was fine; it
>performed flawlessly. However, the variation with the tin pinholed quite a
>bit. Any ideas why this occured? I fire in an electric with a down draft
>venting system and it was a very even firing, my 3 cone packs were all
>equally bent, none more than another. I got up to temp in about 11 hours
>and soaked for 20 minutes. Cooled for about 18 hours before unloading. A
>book or 2 of mine says this may be caused by a immature firing but cone 6
>was flat. Are there other possibilites or is SnO a tricky chemical that
>requires special care, should I have soaked for a longer period?
>
>Also, I would like to thank all of you who take the time to answer my
>posts. I truly appreciate it. I try to email all af you off line but If I
>missed anyone, my appologies.
>
>Paul Raymond
>Franklin, Tn
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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