wallace myers on sun 14 dec 97
I am having trouble with bubbles in some glazes. They
increase when I stir the glaze and never gp away. When I
dip a piece in the glaze it comes out with pin holes. Can
someone tell me how to get rid of the bubbles?
Wallace
GURUSHAKTI on mon 15 dec 97
Dear Wallace:
Sieve your glaze twice through a 200 mesh screen. Overmixing with some of the
jiffy and other mixers may bring up a lot of bubbles. So you may use your
mixer to mix your glaze to a homogenous state and then sieve twice through 200
mesh screen. This may solve the problem.
Regards,
June
Kathi LeSueur on mon 15 dec 97
We need more information to help you with your glaze problem. What
temperature are you firing to? Oxidation or reduction? What is your firing
cycle? The glaze formula would help.
Kathi
wallace myers on tue 16 dec 97
Kathi LeSueur wrote:
> ----------------------------Original
> message----------------------------
> We need more information to help you with your glaze
> problem. What
> temperature are you firing to? Oxidation or reduction?
> What is your firing
> cycle? The glaze formula would help.
>
> Kathi
Thank you for the reply, Kathi.
I am firing to ^6, ox. I have an Olympic kiln, and usually
follow the following schedule; low for 1 hour, on 3 for 1
hour, on 6 for 1 hour, then on high until it cuts off.
I am an amateur who has never had any formal training,
so it would be no revelation if you told me that I don't
know what I am doing.
Here is the recipe that I used;
21 gert borate
16 neph. syn.
11 kaolin
20 whiting
32 silica
5 tin ox.
..15 chrome ox.
Would appreciate any suggestions.
Thanks
Wallace
Kathi LeSueur on thu 18 dec 97
<< Thank you for the reply, Kathi.
I am firing to ^6, ox. I have an Olympic kiln, and usually
follow the following schedule; low for 1 hour, on 3 for 1
hour, on 6 for 1 hour, then on high until it cuts off.
I am an amateur who has never had any formal training,
so it would be no revelation if you told me that I don't
know what I am doing.
Here is the recipe that I used;
21 gert borate
16 neph. syn.
11 kaolin
20 whiting
32 silica
5 tin ox.
...15 chrome ox.
Would appreciate any suggestions.>>
The first thing I would suggest is that you slow down your firing cycle.
Think of your glaze like a cake recipe. If you bake it at 350 degrees for 1
1/2 hours it looks beautiful. If you bake it at 500 degrees for 1/2 it looks
terrible even though it's internal temperature was the same. Glazes need time
to go through their cycle of development. This should'nt be rushed. I'd try
to lengthen to 11 or 12 hours. Put it on low for 3 hours. Then begin bringing
it up in smaller increments. On 3 for 2 hours, on 4 for 2 hours, then on high
till done. If that doesn't take at least 10 hours, bake off putting it on
high.
Your glaze has 20 percent whiting. Whiting looses nearly half of it's
molecular weight during firing. That's a lot of gas to burn off. So you need
to go slow. Hope this helps.
Kathi LeSueur
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