Farren on mon 11 oct 99
Thanks, Ron, for your offer. I don't have the recipe here because it's at the
studio but I'll get it and post it and be happy for any suggestions you can
offer. I like the glaze color a lot so I'd be willing to do some tests and
try to fix the crazing without changing the color too much. It might take a
while for me to do the tests but I'd be happy to post them. I will post the
recipe in a few days.
Patricia
Ron Roy wrote:
> ----------------------------Original message----------------------------
> I need the recipe to give an opinion - any Barium? I may be able to stop
> the crazing as well.
>
> Are you willing to do some experiments and post them to ClayArt?
>
> RR
>
> >----------------------------Original message----------------------------
> >Hi all. I recently started firing at a studio that has a gas kiln and am
> >using a cranberry glaze (Pete's Cranberry) which has crazed a lot on the
> >clay I'm using. I think it does it on some other clays, too. It's being
> >fired to cone 10. I like the color thought not the crazing but I'm
> >willing to ignore the crazing if it doesn't cause a health hazard on
> >pots for serving food. I know the clay is vitrified but are there any
> >safety issues I should be aware of if I continue to use this glaze?
> >Thanks for any info you can give me on this.
> >
> >Patricia Farren
>
> Ron Roy
> 93 Pegasus Trail
> Scarborough
> Ontario, Canada
> M1G 3N8
> Evenings 416-439-2621
> Fax 416-438-7849
Ingeborg Foco on tue 12 oct 99
Ron,
I too have been experimenting with Pete's Cranberry. It is beautiful, runs
badly, and crazes horribly. However, it is worth further experimenting. I
have tried it with several clay bodies. This time I thought I would try to
increase the silica in the clay body to see if that helps any. I don't know
if Patricia has the same recipe. but this is mine.
^10 Reduction
Custer Feldspar 74
Gerstle Borate 10
Whiting 11
Flint 5
Add: Copper Carb .35
Tin Oxide 1.0
Any suggestions will be sincerely appreciated.
Ingeborg
Ron Roy on wed 13 oct 99
Hi Ingeborg,
I've reduced the expansion so it will be more likely to fit some stoneware
clays but I'm not too hopeful for Porcelains. I'm not sure the colour will
be the same but it's worth a try. If it runs increase the EPK till it stops
but don't expect the colour to be the same.
I am willing to try again if you post the results to this list.
Ron's revisions to lower expansion of Petes Red c10 reduc.
Custer - 53.0 (G200 will work as well - I prefer it - see below)
Frit 3134 - 15.0
Whiting - 10.0
EPK - 10.0
Silica - 12.0
Total - 100.0
Copr Carb. - 0.35
Tin oxide - 1.0 ( I would try with tin - 2.0 and 3.0.)
G 200 - 49.5
Frit 3134 - 15.0
Whiting - 10.0
EPK - 10.0
Silica - 15.5
Total - 100.0
Copr Carb. - 0.35
Tin oxide - 1.0 ( I would try with tin - 2.0 and 3.0.)
>----------------------------Original message----------------------------
>Ron,
>
>I too have been experimenting with Pete's Cranberry. It is beautiful, runs
>badly, and crazes horribly. However, it is worth further experimenting. I
>have tried it with several clay bodies. This time I thought I would try to
>increase the silica in the clay body to see if that helps any. I don't know
>if Patricia has the same recipe. but this is mine.
>
>^10 Reduction
>
>Custer Feldspar 74
>Gerstle Borate 10
>Whiting 11
>Flint 5
>
>Add: Copper Carb .35
> Tin Oxide 1.0
>Ingeborg
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
David Hewitt on thu 14 oct 99
Ingeborg,
Yes, increasing the silica should help. However I think it would be
better to also add some china clay in order to keep the Al2O3/SiO2 ratio
similar. This would give you the best chance keeping the same glaze
properties.
If you added 1 EPK and 3 Silica you reduce the expansion coefficient
from something like 6.21 to 5.99 linear x 10-6/oC
A progression blend keeping the EPK and Silica additions in this ratio
of 1 to 3 will keep the Al2O3/SiO2 nearly constant
David
In message , Ingeborg Foco writes
>----------------------------Original message----------------------------
>Ron,
>
>I too have been experimenting with Pete's Cranberry. It is beautiful, runs
>badly, and crazes horribly. However, it is worth further experimenting. I
>have tried it with several clay bodies. This time I thought I would try to
>increase the silica in the clay body to see if that helps any. I don't know
>if Patricia has the same recipe. but this is mine.
>
>^10 Reduction
>
>Custer Feldspar 74
>Gerstle Borate 10
>Whiting 11
>Flint 5
>
>Add: Copper Carb .35
> Tin Oxide 1.0
>
>Any suggestions will be sincerely appreciated.
>
>Ingeborg
>
--
David Hewitt
Ingeborg Foco on thu 14 oct 99
Hi Ron,
Thanks for your suggestions on Pete's Cranberry glaze.
ABSOLUTELY, I WILL REPORT TO THE GROUP OF ALL MY RESULTS
I should have mentioned that I have slightly altered the original recipe as
per "Ceramic Spectrum" Robin Hopper's guidelines. (doing away with the
fractions) I did not alter the colorants but will this next time.
I am presentley using a commercial body but experimenting mixing my own.
Hopefully, I will have more control over problems such as crazing. I'm
trying to do all of this testing so that all of the glitches will be worked
out by the time I move my studio south to Florida.
Looking for a clay body to meet all of my needs is time consuming as well. I
figure it will take me about a month to get ready for my next firing. My
kiln is fairly large and since samples don't take up much space, I have to
make a fair number of pots in addition to all of the testing.
Thanks again
Ingeborg
tgschs10 on thu 14 oct 99
Not only all of the aforementioned problems, I find it also applies
horribly, is impossible to touch up and in general is difficult to apply and
fire.
----- Original Message -----
From: Ingeborg Foco
To:
Sent: Tuesday, October 12, 1999 9:58 AM
Subject: Re: Crazing glaze (Ron Roy)
> ----------------------------Original message----------------------------
> Ron,
>
> I too have been experimenting with Pete's Cranberry. It is beautiful,
runs
> badly, and crazes horribly. However, it is worth further experimenting.
I
> have tried it with several clay bodies. This time I thought I would try
to
> increase the silica in the clay body to see if that helps any. I don't
know
> if Patricia has the same recipe. but this is mine.
>
> ^10 Reduction
>
> Custer Feldspar 74
> Gerstle Borate 10
> Whiting 11
> Flint 5
>
> Add: Copper Carb .35
> Tin Oxide 1.0
>
> Any suggestions will be sincerely appreciated.
>
> Ingeborg
>
Tasha Olive on sun 17 oct 99
Dear David and Ron, PLEEASE excuse me for breaking into this thread but I am
hoping that Ron or one of our other glaze gurus can help with a problem I
just ran across. I have a trash can full of a high silica white glaze that I
just have not had need for the last year or so, anyway upon opening today
discovered it is like a rock at the bottom of the glaze water. Is there
anything I can do short of drying it out and pulverizing to remix?I'm really
hoping someone knows of another solution. TIA Tasha
-----Original Message-----
From: David Hewitt
To: CLAYART@LSV.UKY.EDU
Date: Thursday, October 14, 1999 10:04 AM
Subject: Re: Crazing glaze (Ron Roy)
----------------------------Original message----------------------------
Ingeborg,
Yes, increasing the silica should help. However I think it would be
better to also add some china clay in order to keep the Al2O3/SiO2 ratio
similar. This would give you the best chance keeping the same glaze
properties.
If you added 1 EPK and 3 Silica you reduce the expansion coefficient
from something like 6.21 to 5.99 linear x 10-6/oC
A progression blend keeping the EPK and Silica additions in this ratio
of 1 to 3 will keep the Al2O3/SiO2 nearly constant
David
In message , Ingeborg Foco writes
>----------------------------Original message----------------------------
>Ron,
>
>I too have been experimenting with Pete's Cranberry. It is beautiful, runs
>badly, and crazes horribly. However, it is worth further experimenting. I
>have tried it with several clay bodies. This time I thought I would try to
>increase the silica in the clay body to see if that helps any. I don't know
>if Patricia has the same recipe. but this is mine.
>
>^10 Reduction
>
>Custer Feldspar 74
>Gerstle Borate 10
>Whiting 11
>Flint 5
>
>Add: Copper Carb .35
> Tin Oxide 1.0
>
>Any suggestions will be sincerely appreciated.
>
>Ingeborg
>
--
David Hewitt
Ron Roy on mon 18 oct 99
I suspect your glaze is deflocculated - I don't know why as the materials
in it are not problematic - or is it different than the one included with
this question.
Better send me the recipe that you are working with so I can deal with this
properly - and reformulate so it does not settle out.
In the meantime try dynamite - no no just kidding. The answer is to replace
the water - to get some of the alkali out of the bucket - do it a couple of
times. Second step is to mix up some Epsom salts - hot - very hot water -
one cup and 2 table spoons of Epsom - make sure it dissolves. Put in squirt
bottle and - if the trash can is really full put in 4 table spoons of that
solution with the replacement water. Start digging - or use a paint mixer
on a drill until all the glaze is mixed up again. If it has a tendency to
settle add another tablespoon - mix again - sooner or later it will become
thicker and not settle anymore - thin to application thickness - TEST - to
see if that thickness is still what you want.
The flocculation will take a little while - add the salts, stir well and
let sit for 30 min. Then mix again.
In the meantime - I advise you to let me reformulate that glaze so this
does not happen in the future.
RR
>----------------------------Original message----------------------------
>Dear David and Ron, PLEEASE excuse me for breaking into this thread but I am
>hoping that Ron or one of our other glaze gurus can help with a problem I
>just ran across. I have a trash can full of a high silica white glaze that I
>just have not had need for the last year or so, anyway upon opening today
>discovered it is like a rock at the bottom of the glaze water. Is there
>anything I can do short of drying it out and pulverizing to remix?I'm really
>hoping someone knows of another solution. TIA Tasha
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
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