stephani stephenson on thu 16 aug 07
hi eleanora
the 3195 is a good frit to use at cone 06
seems it provides a more reliable clear, better than
3269, 3134,3124 and less COI than 3110
...i don't have a regular 06 clear i use
consistently
but maybe the folowing info will help
I found 2.5% bentonite best for suspending high
frit glazes
I used the Carleton Ball cone 06 base glaze when i
compared various frits and colorant response
frit 70 %
silica 15%
clay 15%
stephani stephenson
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Eleanora Eden on fri 17 aug 07
Thanks Stephani! This is just the kind of thing I was looking for.
I've tried all those frits plus 3278 3819, and 3336.
I started with Veegum C. Not enough oomph, even at 3%.
I think Laguna told me that Veegum C is 2/3 bentonite, 1/3 CMC,
not the half and half I used to think. So I thought that increasing
the CMC separately might help. And macaloid is just superman
bentonite, so I thought a tiny bit of that would just help.
Anyway, that was the thinking and I will try it with 2.5% bent and
see if that is better.
Thanks,
Eleanora
>hi eleanora
>the 3195 is a good frit to use at cone 06
>
>seems it provides a more reliable clear, better than
>3269, 3134,3124 and less COI than 3110
>
>...i don't have a regular 06 clear i use
>consistently
>but maybe the folowing info will help
>
>I found 2.5% bentonite best for suspending high
>frit glazes
>
>I used the Carleton Ball cone 06 base glaze when i
>compared various frits and colorant response
>
>
>frit 70 %
>silica 15%
>clay 15%
>
>stephani stephenson
>
>
> ____________________________________________________________________________________
>Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user panel and lay it on us. http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7
>
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Paulette Carr on fri 17 aug 07
Eleanora,
In your recipe, the amount of Si is just a little low for where I
like to work in low fire, but your Al2O3 is high (at or above Green &
Cooper ^04 limits). There are several things to try... you could
reduce the ratio of flux to Si... or reduce the Al2O3 keeping the
silica the same, etc.
I have a recipe for you, in which I have lowered the Al2O3 by
lowering the amount of clay, but increased the SiO2 by adding flint/
silica. There should still be enough Al2O3 to keep the glaze from
moving, but you will have to test. Here is my contribution:
Modification A on Clear ^06 #15
Frit 3195 72.1
Frit 3134 12.5
EPK 6.7
Flint 8.7
0.68* CaO
0.32* Na2O
0.39 Al2O3
0.98 B2O3
3.00 SiO2
Si:Al: 7.61
SiB:Al: 10.10
Thermal Expansion: 7.00
Add at least 0.5 -1% bentonite for suspension (since you have so
little clay), plus 1-1.5% VgC (or test to find what works for you,
but the bentonite is necessary.
The SiO2 in your recipe isn't necessarily too low (of course, the
more you have the more durable the glass/glaze - up to a point, where
the glaze contains so much that it does not mature), but I would have
thought that the ratio of Si:Al in your recipe is too low to yield a
good gloss. However, you do have an abundance of B2O3 (about 2-3
times what I use). Since you told us that the glaze is very clear &
glossy at ^06, so I am guessing that B2O3 is behaving as both a flux
and a glass former and you are probably making a borosilcate glass.
You might check with others to find out if the borosilcate glasses
are as hard/durable (or maybe harder) than just silicates.
Interesting question. Remember to test your glaze on your body for
crazing, shivering, and acid attack, marking etc.
A worthy project!!!
My best,
Paulette
On Aug. 16, 2007, Eleanora Eden wrote:
After some testing I have found that this glaze below seems to work
reliably at
^06 as a nice clear. I have been adding 1% CMC gum and 1% veegum C
and .25% macaloid to harden it up. None of these alone seems to do the
job. I tried to find a recipe with higher clay but wasn't successful.
Does anyone have any general or particular comments on this? Anybody
using their own ^06 clear who would like to share their recipe with me?
I feel like I am reinventing the wheel by myself here and would like
some
imput.
I tam thinking about raising the silica a bit.
Paulette Carr
Paulette Carr Studio
Member/Potters Council
St. Louis, MO
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