Alisa Clausen on fri 29 feb 08
On Wed, 27 Feb 2008 22:53:43 -0500, John Post
wrote:
>Hi Alisa,
>I have a few questions for you.
>Why do you let your kiln max cool down to 900c and then hold for only
>30 minutes?
>(In my experience with slow cooling I have found that it takes longer
>than 30 minutes to get nice crystal growth.)
>
>I noticed you tested Jen's Juicy Fruit but you omitted the soda ash
>and the titanium. I'm just curious as to why did this?
Hi John,
I looked at the original recipe from your site and because the top
ingredients equal 100, I chose to omit the additives below the recipe
which are described as variations. However, it could be that Soda Ash and
Titanium are part of the base. I changed the base in any case to omit 9
Lithium and I do not add Soda Ash (what is your source?) because I do not
really know where to source it from? I have used ordinary household soda
used for cleaning, but have always been unsure about this material. It is
obviously Sodium, but what do we use when a recipe calls for Soda ash.
The soda wood fire people source it from salt? It seems to be an additive
and that is why, in this case I omitted it.
Looking at your photos, the Cu version is crazed. How did the Iron
version do? It does not appear crazed from the photo. I am curious again,
because I find many bases which craze alone or worsened with Cu, fit
better with an addition of iron. We have talked about COE and oxides
before because this is a point of interest of mine.
As far as my ramps, I think it important to individualize the cool down to
suit one's kiln, glazes and desired results. I found that the ramps in
MC6G make my glazes (and the books glazes) mostly too fluid to runny and
some are overfired with bubbles. I adjusted the ramps also to get a
better result from the Boron Frit I use instead of F3134 which I do not
have, only small amounts for testing. My frit has 0.7 Barium in it and
appears to melt too much with a slower ramp than the one I currently use.
I get fine mat crystals and Titanium crystals with the ramp I use.
To each his own heatwork!
You can send me the base version of Juicy fruit you use and I will test
again.
Best regards from Alis in Denmark
>
>>> Firing ramp with an electric controller is:
>>> 100c p/h to 600c (212f - 1112f)
>>> 150c p/h to 1140c (302f - 2084f)
>>> 80c p/h to 1220c (176f - 2228f)
>>> 15 min. soak
>>> cool down max. to 900c (1652f)
>>> Hold 30 minutes
>>>
>>> Shut off kiln
>
John Post on fri 29 feb 08
Hi Alisa,
I only tested this glaze myself, because it had a strange set of
ingredients in it. The 9 lithium carbonate and 10 soda ash piqued my
interest. I knew that these two fluxes would be big players in this
glaze and they are. You might want to try testing it with those
ingredients in the glaze. The titanium is also important as a seeding
agent for crystal development.
I purchase my soda ash from Rovin's ceramics in Taylor Michigan
1-734-374-0010 is their phone number.
Yes the copper version of my glaze crazed. That's what I like about
it. The iron may have crazed as well but I did not look at it with
magnification. I am not searching for stable glazes right now. When
I run a Currie grid of a glaze, I am looking for visually interesting
glazes....glazes that have some variability to them and an active
surface. I don't want them to look like they came out of the big
electric toaster. When I need a glaze that is safe to use with food, I
use the calcium matte glazes that I have had lab tested or I use RR's
licorice black.
I agree with you about the heatwork, we all set our own profiles based
on our needs. The reason I was asking about your profile was that I
wanted to know how similar or dissimilar to mine it was. Then I could
make inferences about whether or not to test a glaze based on your
results.
Thanks for all you contribute to this list.
Do you ever test using Ian Currie's grid method? It opens up a whole
new way of developing and thinking about glazes.
John Post
Sterling Heights, Michigan
http://www.johnpost.us :: cone 6 glaze website ::
http://www.wemakeart.org :: elementary art website ::
>However, it could be that Soda Ash and Titanium are part of the
base. I changed the base in any case >to omit 9 Lithium and I do not
add Soda Ash (what is your source?)
>Looking at your photos, the Cu version is crazed. How did the Iron
version do?
>I get fine mat crystals and Titanium crystals with the ramp I use.
To each his own heatwork!
Alisa Clausen on sat 1 mar 08
Hi John
Yes, I wil retest the Juicy fruit with the Lithium (although 9 Lith. makes
me shiver....ha ha that was a ceramic joke....yes, it is Saturday and I am
slightly bored) and I am sure that the Titanium with give a different
look to the glaze I tested. So, will do.
It takes time to figure out the best firing schedule for "most" of the
glazes we fire. However, if I do a kiln full of glosses, I omit the slow
cool. If there are any other versions of a mat, or micro crystals, I slow
cool. It is very rare that I hold at the top and shut off the kiln. Only
when I have a load of underglazes and I actually would like them to have a
little less heat, to retain a brighter appearence.
Ian Currie has been my guest twice. I was the happiest potter alive to
have a living, walking, talking glaze genius under my roof. He taught me
grid and sometimes I use it. But I use it just like you, to pluck out
interesting surfaces and color. So, usually I am taking the glazes that
have "faults". It is a very interesting and informative approach to
glazes.
I like to use a whole mix of a lot of ideas and approahces, I am not so
much to one school. I obviously want stable and food safe glazes for
table ware, I could make Gartside concoctions all day long for excitiment
when opening the kiln and grids tell 35 stories on one tile!~so there is
enough to keep us all interested and busy. Hopefully so much I cannot
make any more ceramic jokes!
We can stay in touch with our glaze results.
Best regards from Alisa in Denmark
>Hi Alisa,
>
>I only tested this glaze myself, because it had a strange set of
>ingredients in it. The 9 lithium carbonate and 10 soda ash piqued my
>interest. I knew that these two fluxes would be big players in this
>glaze and they are. You might want to try testing it with those
>ingredients in the glaze. The titanium is also important as a seeding
>agent for crystal development.
>
>I purchase my soda ash from Rovin's ceramics in Taylor Michigan
>1-734-374-0010 is their phone number.
>
>Yes the copper version of my glaze crazed. That's what I like about
>it. The iron may have crazed as well but I did not look at it with
>magnification. I am not searching for stable glazes right now. When
>I run a Currie grid of a glaze, I am looking for visually interesting
>glazes....glazes that have some variability to them and an active
>surface. I don't want them to look like they came out of the big
>electric toaster. When I need a glaze that is safe to use with food, I
>use the calcium matte glazes that I have had lab tested or I use RR's
>licorice black.
>
>I agree with you about the heatwork, we all set our own profiles based
>on our needs. The reason I was asking about your profile was that I
>wanted to know how similar or dissimilar to mine it was. Then I could
>make inferences about whether or not to test a glaze based on your
>results.
>
>Thanks for all you contribute to this list.
>
>Do you ever test using Ian Currie's grid method? It opens up a whole
>new way of developing and thinking about glazes.
>
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