Chris K on tue 15 apr 08
I=92ve used this matte glaze as a base and it works well when layered under
other glazes. I like the texture and the color response. By itself it
pinholes. In researching the glaze pinholing is common. Has anyone
experimented in altering or have an idea of how to change the glaze to
reduce the pinholing?
Pinnell Strontium Matt Glaze (cone 6)
Lithium carb..........1
Strontium Carb.......20
Nepheline Syenite....60
Ball Clay............10
Flint.................9
=3D 100%
White-Titanium Dioxide 5%
Chris K
Fred Parker on wed 16 apr 08
Hi Chris:
I can't offer anything for this particular glaze; however, I have had a
similar experience with another glaze that might have some relevance. I
have used Ron and John's "Carribean Sea Green" a lot. It is a different
type glaze containing zinc, but I noticed that I have pinholing problems
with it fairly often. After many pinholed pots I noticed pinholing was
happening MUCH more on certain clays and much less on others. Brown clays
with speckling (usually from manganese) make this glaze pinhole for me,
while white clays either do not or greatly reduce the amount of
pinholing. Covering it with a clear glaze almost always eliminates
pinholing, but it changes the color somewhat -- not altogether badly.
This might have nothing to do with your experience with your glaze, but I
just wanted to make the point that it is not always the glaze that is
pinholing. Sometimes it is the clay.
Regards,
Fred Parker
On Tue, 15 Apr 2008 08:49:32 -0500, Chris K
wrote:
>I=92ve used this matte glaze as a base and it works well when layered under=
>other glazes. I like the texture and the color response. By itself it
>pinholes. In researching the glaze pinholing is common. Has anyone
>experimented in altering or have an idea of how to change the glaze to
>reduce the pinholing?
>
>Pinnell Strontium Matt Glaze (cone 6)
>Lithium carb..........1
>Strontium Carb.......20
>Nepheline Syenite....60
>Ball Clay............10
>Flint.................9
>=3D 100%
>
>White-Titanium Dioxide 5%
>
>Chris K
>
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Alisa Clausen on thu 17 apr 08
Hi Chris
This is a glaze I use very much of. It is a glaze that likes to be
thick. However, if it is too thick, it will pinhole. What is too thick?
I use the glaze like a thin yogurt and dip only one time. I think you
should test it with some different viscosities and layering and then you
will find the right thickness. I rarely have pinholes, but rather a very
smooth mat. There are also variations of this glaze, Pete had pubished in
Clay Times. All of the recipes and photos are on my Flickr site at
http://www.flickr.com/photos/glazes/sets/
there is also one he calls Seafoam I use. Both glazes normally fire
smooth and mat.
It is also true that they like to be under white glazes. Very smooth.
Good luck,
Alisa in Denmark
On Tue, 15 Apr 2008 08:49:32 -0500, Chris K
wrote:
>I=92ve used this matte glaze as a base and it works well when layered under=
>other glazes. I like the texture and the color response. By itself it
>pinholes. In researching the glaze pinholing is common. Has anyone
>experimented in altering or have an idea of how to change the glaze to
>reduce the pinholing?
>
>Pinnell Strontium Matt Glaze (cone 6)
>Lithium carb..........1
>Strontium Carb.......20
>Nepheline Syenite....60
>Ball Clay............10
>Flint.................9
>=3D 100%
>
>White-Titanium Dioxide 5%
>
>Chris K
>
Chris K on fri 18 apr 08
Fred,
Thank you for reminding me about the clay causing pinholing. I'm going to
bisque the next load hotter and see if that works.
-Chris K
On Wed, 16 Apr 2008 15:13:46 -0500, Fred Parker wrote:
>Hi Chris:
>
>I can't offer anything for this particular glaze; however, I have had a
>similar experience with another glaze that might have some relevance. I
>have used Ron and John's "Carribean Sea Green" a lot. It is a different
>type glaze containing zinc, but I noticed that I have pinholing problems
>with it fairly often. After many pinholed pots I noticed pinholing was
>happening MUCH more on certain clays and much less on others. Brown clays
>with speckling (usually from manganese) make this glaze pinhole for me,
>while white clays either do not or greatly reduce the amount of
>pinholing. Covering it with a clear glaze almost always eliminates
>pinholing, but it changes the color somewhat -- not altogether badly.
>
>This might have nothing to do with your experience with your glaze, but I
>just wanted to make the point that it is not always the glaze that is
>pinholing. Sometimes it is the clay.
>
>Regards,
>
>Fred Parker
Chris K on fri 18 apr 08
Alisa- Thank you for the link to your tests. I have used your glaze work
in the past when looking for samples to try. I'll go through them again
and try a few more in my kiln. I'll also take more time glazing to note
and record the thickness.
-Chris K
Ron Roy on sun 20 apr 08
Hi Chris,
Calcium carb decomposes at about 825C into CaO and CO2, Strontium Carb at 10=
75C.
There are mentions in some glaze books about strontium being a problem if
you don't want bubbles in your glaze. Thats because the CO2 is released
later and may have trouble getting out through the glaze. Try giving it a
longer soak and/or a longer time near the end of the firing on the way up -
and/or a slower cool for the first 100C
RR
>I=92ve used this matte glaze as a base and it works well when layered under
>other glazes. I like the texture and the color response. By itself it
>pinholes. In researching the glaze pinholing is common. Has anyone
>experimented in altering or have an idea of how to change the glaze to
>reduce the pinholing?
>
>Pinnell Strontium Matt Glaze (cone 6)
>Lithium carb..........1
>Strontium Carb.......20
>Nepheline Syenite....60
>Ball Clay............10
>Flint.................9
>=3D 100%
>
>White-Titanium Dioxide 5%
>
>Chris K
Ron Roy
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Alisa Clausen on thu 24 apr 08
On Sun, 20 Apr 2008 16:01:27 -0500, Ron Roy wrote:
>Hi Chris,
>
>Calcium carb decomposes at about 825C into CaO and CO2, Strontium Carb at
1075C.
>
>There are mentions in some glaze books about strontium being a problem if
>you don't want bubbles in your glaze. Thats because the CO2 is released
>later and may have trouble getting out through the glaze. Try giving it a
>longer soak and/or a longer time near the end of the firing on the way
up -
>and/or a slower cool for the first 100C
>
>RR
I get a very smooth glaze almost always except as we talked about if it is
very, very thick. My ramp is only 100c per hour from 1100c to the final
1220c, I soak 15-30 minutes at the top, and then soak at 900c for one hour
on the way down.
Best regards, Alisa in Denmark
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