Craig Martell on wed 30 mar 05
Lela asked:
> Is there something I can look for in the recipes ahead of time to avoid
> the problem...or just see what happens?
Hi:
Any lithium bearing materials in the glaze?
regards, Craig Martell Hopewell, Oregon
Craig Martell on thu 31 mar 05
Lela was wondering:
>Is this sort of breakage common...when the liner is a different
>formulation than the outside glazed?
Hello Lela:
Well, no this sort of thing isn't "common" but it does happen now and
then. I lost a bunch of vases many years ago when I was firing cone 6
electric. Spiral cracks from foot to lip and the pots were totally
destroyed. It was a high lithium satin matt and I used it inside the pots.
Usually you get stuff like crazing and shivering but cracking from the
glaze/clay incompatibility is basically a very extreme case.
If you would feel like posting the glaze recipe it would be possible to
make some calculated opinions about the problem. It's always very specific
to the clay and glaze relationship. If the glaze looked ok you could try
it on some other claybodies if you wanted. Glazes can be "off" and clays
can be unbalanced too. Hard to tell without the recipes.
regards, Craig Martell Hopewell, Oregon
lela martens on thu 31 mar 05
Ahh, glad you`re all back,
Some time ago I painted desighns on 5 medium sized pots with different
colours of a commercial glaze. On the insides I used a mixed-myself satiny
glaze, slowly fired up and down, cone 6. All five were found broken in half
vertically on opening the kiln. None of the other pots in that load broke.
I presumed a difference of expansion of the glazes was the cause..maybe
wrongly...I want to use a matte, decorative glaze on the outside of some
pieces, with a stable liner glaze, both home mixed.
It`s a bit odd, since only glazing the inside, leaving the outside naked
clay has never caused a problem. Have those of you who use liner glazes had
this breakage? Is there something I can look for in the recipes ahead of
time to avoid the problem...or just see what happens?
Thanks from Lela, where we have had warm sun, wind, blue skies and a small
blizzard in the last 6 hours.
lela martens on thu 31 mar 05
Hi Craig,
Nope. Not in the group that broke and there won`t be in these two glazes I
plan to use either.
Is this sort of breakage common...when the liner is a different formulation
than the outside glazed?
Best wishes, Lela
>Lela asked:
>> Is there something I can look for in the recipes ahead of time to avoid
>>the problem...or just see what happens?
>
>Hi:
>Any lithium bearing materials in the glaze?
>
>regards, Craig Martell Hopewell, Oregon
lela martens on fri 1 apr 05
Hi Craig,
I had painted the outsides with different colours of a commercial glaze, so
have not any formulation information. The inside, as I remember, a simple
white satin with common ingredients.
Since you say the breakage is not a common problem,(good to hear) I will go
ahead and give it a try...with only two pots the first time, with two
different clays.
Thank you very much for taking the time.
Best wishes, Lela
>Lela was wondering:
>>Is this sort of breakage common...when the liner is a different
>>formulation than the outside glazed?
>
>Hello Lela:
>
>Well, no this sort of thing isn't "common" but it does happen now and
>then. I lost a bunch of vases many years ago when I was firing cone 6
>electric. Spiral cracks from foot to lip and the pots were totally
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