Cynthia Aldrich on thu 26 feb 98
I have used the same blue semimat glaze (surface rutile crystals), cone
9 electric, for 20 years. I use it on EVERYTHING. Here's what has
happened - maybe 2 or 3 times over the years I've mixed up a new batch
of this glaze and it has turned out a shiney semi-transparent dark
blue. I have always assumed that I wasn't paying attention when I
weighed out the raw chemicals because after realizing the bad glaze I
mixed up a new batch it has always returned to the regular semi-mat blue
glaze. This time however, it has not. I had bought some new CoCO3 and
had used it on the bad batch so I thought it was the coCO3. I ordered
some more CoCO3 from a different source and the next batch of glaze was
fine. About 3 weeks later I mixed up another batch and no good -
shiney. I had opened a new bag of either Custer or Silica and can't
remember which. So I bought new silica and Custer but no- still
shiney. Any suggestions???
Blue Glaze, cone 9 ox
Custer -38
dolomite -17
whiting -6
epk -22
silica -17
plus 1% CoCo3
2% powdered rutile
1% granular rutile
This glaze will go shiney if over fired, but that hasn't occured.
Thanks for ANY suggestions.
Cindy Aldrich
Durham, NC
aldric3@IBM>NET
Carolyn Sawyer on thu 6 may 99
Since I must be the only one in the entire world that has a batch of Rewood
Matt, Orchre Matt and Kenzan's Ash, maybe there's somebody out there that
can suggest a glaze they have that's similar. I didn't get one response):
The two matts were a mottled Red/Brown/Gold and the ash, a tan with texture.
^6 OX
Thanks for you r help.
Carolyn
Campobello We're scraping the bottom of these buckets and everyone's asking
me for more. I'm not a teacher..just a newbie!
jklust on fri 7 may 99
Carolyn, I have purchased redwood matt and ochre matt from laguna clay
company. I am not sure if it is the same glazes you are talking about but
you could call them and they will give you the chemicals that are in them
(won't give you the recipe) but you could start there???Kim
-----Original Message-----
From: Carolyn Sawyer
To: CLAYART@LSV.UKY.EDU
Date: Thursday, May 06, 1999 9:48 AM
Subject: Glaze help
>----------------------------Original message----------------------------
>Since I must be the only one in the entire world that has a batch of Rewood
>Matt, Orchre Matt and Kenzan's Ash, maybe there's somebody out there that
>can suggest a glaze they have that's similar. I didn't get one response):
>The two matts were a mottled Red/Brown/Gold and the ash, a tan with
texture.
>^6 OX
>Thanks for you r help.
>Carolyn
>Campobello We're scraping the bottom of these buckets and everyone's
asking
>me for more. I'm not a teacher..just a newbie!
Chris Schafale on fri 7 may 99
Hi Carolyn,
You might try the two iron red glazes I posted today, though it
sounds like they're more red and less brown/gold than yours (at least
in my kiln).
Chris
> ----------------------------Original message----------------------------
> Since I must be the only one in the entire world that has a batch of Rewood
> Matt, Orchre Matt and Kenzan's Ash, maybe there's somebody out there that
> can suggest a glaze they have that's similar. I didn't get one response):
> The two matts were a mottled Red/Brown/Gold and the ash, a tan with texture.
> ^6 OX
> Thanks for you r help.
> Carolyn
> Campobello We're scraping the bottom of these buckets and everyone's asking
> me for more. I'm not a teacher..just a newbie!
>
>
Light One Candle Pottery
Fuquay-Varina, NC
candle@intrex.net
Patrice Murtha on mon 13 nov 00
I have been currently using this glaze in a salt kiln.
VC Pam Frederick's
Nepheline Syenite 44
Gerstley Borate 12
Whiting 12
Lithium Carb 6
EPK 13
Flint 13
Add:
Titanium Dioxide 11
Copper Carb 6
It really is a beautiful glaze-nice copper greens/white pearl where it
breaks. I'm firing at school in a downdraft kiln and many of the sculpture
students before me have been experimenting with straight copper carbonate
on their sculptures. My theory is that there is a lot of residual copper
in the kiln and this is changing the composition of my glazes. This is not
the only glaze this has happened to. Am I way off the mark or could this
be a logical assumption? Could I reduce the amount of copper in my glase
to counteract this? Any help would be appreciated.
John Hesselberth on mon 13 nov 00
Hi Patrice,
There is probably some residual copper in the kiln, but I doubt that it
would be enough to affect a copper-containing glaze. It might affect
other glazes.
I must make a couple comments about this glaze though. It will be very
unstable itself. The copper level is very high and the silica level is
very low. No way would I use it on a functional surface. I haven't
found a glaze yet that will hold more than 5% copper carbonate without
leaching a lot. And that is with a good stable base glaze which this
glaze definitely is not. With the low level of silica in this glaze I
will bet that vinegar or lemon juice will draw the color right out of it
in a few hours.
If your work is sculptural or non-functional, fine. Please find another
glaze if you are making dinnerware.
Regards, John
Patrice Murtha wrote:
>I have been currently using this glaze in a salt kiln.
>
>VC Pam Frederick's
>
>Nepheline Syenite 44
>Gerstley Borate 12
>Whiting 12
>Lithium Carb 6
>EPK 13
>Flint 13
>Add:
>Titanium Dioxide 11
>Copper Carb 6
>
>
>It really is a beautiful glaze-nice copper greens/white pearl where it
>breaks. I'm firing at school in a downdraft kiln and many of the sculpture
>students before me have been experimenting with straight copper carbonate
>on their sculptures. My theory is that there is a lot of residual copper
>in the kiln and this is changing the composition of my glazes. This is not
>the only glaze this has happened to. Am I way off the mark or could this
>be a logical assumption? Could I reduce the amount of copper in my glase
>to counteract this? Any help would be appreciated.
John Hesselberth
Frog Pond Pottery
P.O. Box 88
Pocopson, PA 19366 USA
EMail: john@frogpondpottery.com web site: http://www.frogpondpottery.com
"It is, perhaps, still necessary to say that the very best glazes cannot
conceal badly shaped pots..." David Green, Pottery Glazes
Craig Martell on sat 9 dec 00
Les wanted to know:
>>Can anyone out there make a suggestion as to a change I might make to get
>>a soft gloss surface.
Hi:
Add some silica. This glaze has a low silica/alumina ratio at about 5 to
1. In terms of limits, it's too low for a balanced cone 10 glaze. You
could use another mole-plus of silica. So blend in about 25 to 30% more at
5 gram intervals and see what you get. If you want to see some very
dramatic results do a Currie 35 glaze biaxial. This will cover variables
that you wouldn't think of exploring. To do this, you would need his 2nd
book or you could look at his website and figure it out maybe.
later, Craig Martell in Oregon
Bill Edwards on tue 25 mar 03
gordon jones wrote:
> help i'm a newbie and i messed it up, had a great
> glaze and used it with
> nothing but success,ran out mixed it again and now
> it will not behave .
If I were going to guess I would take a stab at the
zinc oxide. Personally I don't like the stuff. Try
calcining it or moving it out. Somewhere a slip up
apparently occured and like stated, cobalt is a
powerful flux but I believe you would see that in
oxidation based on the fired color if you over-dosed
it. I would re-look at the base ingredients again and
make a small batch and see what happens.
Bill Edwards
=====
http://www.tallapoosariverpottery.com/
Bill Edwards
PO Box 267
Lafayette, AL, 36862
__________________________________________________
Do you Yahoo!?
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Patricia Minnes on sun 30 may 10
There was a clayart discussion regarding additions of ?? to a glaze which
helps to keep the glaze on the pot rather than having it rub off on your
fingers when holding the pot to be dipped.
I carefully filed the information for future use...............exactly,
where ???
Thanks for refreshing my memory.
Patsi Minnes
--
patsi.minnes@gmail.com
Ron Roy on mon 31 may 10
HI Patricia,
I can do that by replacing the kaolin with ball clay - I need the
recipe ad what kind of kaolin are you using and what kind of ball clay
can you get.
RR
Quoting Patricia Minnes :
> There was a clayart discussion regarding additions of ?? to a glaze which
> helps to keep the glaze on the pot rather than having it rub off on your
> fingers when holding the pot to be dipped.
> I carefully filed the information for future use...............exactly,
> where ???
> Thanks for refreshing my memory.
> Patsi Minnes
>
> --
> patsi.minnes@gmail.com
>
Robert Harris on mon 31 may 10
Both CMC - an organic additive that is a modern equivalent of Gum Arabic an=
d
Veegum T (a bentonite-like mineral) will help do this - the glaze gets much
harder on the pot.
There are a number of discussion in the archive about how much to add. I
wouldn't add much more that 0.5% of either. YMMV.
The problem is that they both alter the viscosity of the glaze slip which
means you will have to learn how to apply the new glaze. The glaze will,
(for a give specific gravity) be a lot 'thicker.
CMC also has the problem that it is prone to decompose after a few months -
you can add preservatives that will help, but they're pretty toxic (e.g.
formaldehyde) or alter the pH and therefore floculation (e.g. bleach).
hope this helps jog your memory
Robert
On Sun, May 30, 2010 at 4:30 PM, Patricia Minnes wr=
ote:
> There was a clayart discussion regarding additions of ?? to a glaze which
> helps to keep the glaze on the pot rather than having it rub off on your
> fingers when holding the pot to be dipped.
> I carefully filed the information for future use...............exactly,
> where ???
> Thanks for refreshing my memory.
> Patsi Minnes
>
> --
> patsi.minnes@gmail.com
>
--
----------------------------------------------------------
Lynn Goodman Porcelain Pottery on mon 31 may 10
You can add .25 cmc to the dry mix, mix it up with your fingers to
disperse it, then mix the glaze slightly thicker than normal and sieve
as usual. Use cold water to stop it from gelling prematurely and
clumping up.
Lynn
On May 30, 2010, at 4:30 PM, Patricia Minnes wrote:
> There was a clayart discussion regarding additions of ?? to a glaze
> which
> helps to keep the glaze on the pot rather than having it rub off on
> your
> fingers when holding the pot to be dipped.
> I carefully filed the information for future
> use...............exactly,
> where ???
> Thanks for refreshing my memory.
> Patsi Minnes
>
> --
> patsi.minnes@gmail.com
Lynn Goodman
Fine Porcelain Pottery
Cell 347-526-9805
www.lynngoodmanporcelain.com
Bonnie Staffel on tue 1 jun 10
Robert, there must be two grades of CMC. Whatever one I have has never
molded or gone bad on storage. I purchased it so long ago that I don't
recall the supplier, but it was a ceramic supplier. I have mixed it up
separately and used it as a liquid gum way back in the early 70s. Now I =3D
add
it dry and blend with one of the dry ingredients and add the mix to hot
water to dissipate the CMC faster. I go easy on the ratio of water to =3D
dry
ingredients and then with my hydrometer, I add water until the mix reads =
=3D
17
for my particular glaze.=3D20
I usually make a huge batch of glaze to last me for quite a while. Still
never any mold or spoilage.
Bonnie Staffel
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
DVD=3DA0 Throwing with Coils and Slabs
DVD=3DA0 Introduction to Wheel Work
Charter Member Potters Council
Robert Harris on tue 1 jun 10
On the topic of CMC I was just quoting the "received" wisdom. For me,
occasionally glazes with CMC in it smell a bit funny if they've been left
for a few weeks - but a good stir tends to get rid of it (and nothing as ba=
d
as good old fashioned bone ash). In other words I tend to agree with you.
Generally 5 gallons of glaze only lasts a month or so at the most when I'm
really hitting hard anyway. Personally I use Veegum T most of the time. And
that (like CMC) should generally be dissolved in water first. I personally
keep a big concentrated jar of both and add a dash to anything that seems t=
o
need it.
Robert
On Tue, Jun 1, 2010 at 11:18 AM, Bonnie Staffel wro=
te:
> Robert, there must be two grades of CMC. Whatever one I have has never
> molded or gone bad on storage. I purchased it so long ago that I don't
> recall the supplier, but it was a ceramic supplier. I have mixed it up
> separately and used it as a liquid gum way back in the early 70s. Now I a=
dd
> it dry and blend with one of the dry ingredients and add the mix to hot
> water to dissipate the CMC faster. I go easy on the ratio of water to dry
> ingredients and then with my hydrometer, I add water until the mix reads =
17
> for my particular glaze.
>
> I usually make a huge batch of glaze to last me for quite a while. Still
> never any mold or spoilage.
>
> Bonnie Staffel
>
> http://webpages.charter.net/bstaffel/
> http://vasefinder.com/bstaffelgallery1.html
> DVD Throwing with Coils and Slabs
> DVD Introduction to Wheel Work
> Charter Member Potters Council
>
--
----------------------------------------------------------
Lynn Goodman Porcelain Pottery on tue 1 jun 10
Paul,
You are FAR more organized than me! I generally mix up glaze at the
spur of the moment, as I figure out that I need it, so I wouldn't have
the cmc water mixed up yet. Also, if you add it to the dry mix, you
get exactly the amount you want; no guessing if there's enough cmc in
the batch.
I actually use a lot more than .25% since I paint my glazes instead of
dipping/pouring them--I use 2%, and mix my glazes thick. I have tried
any number of ways to make it easier to add cmc and sieve it in, but I
always come back to adding the precise amount into the dry mix.
Lynn
On Jun 1, 2010, at 9:01 AM, paul gerhold wrote:
> Lynn,
>
> CMC works much better if you add it to the water a day or so in
> advance and then use the water/CMC mix too make up your glaze. This
> eliminates the problem of clumping and clogging on the sieve screen.
>
> Paul
>
>
>
>
>
>
Lynn Goodman
Fine Porcelain Pottery
Cell 347-526-9805
www.lynngoodmanporcelain.com
paul gerhold on tue 1 jun 10
Lynn,
CMC works much better if you add it to the water a day or so in advance and
then use the water/CMC mix too make up your glaze. This eliminates the
problem of clumping and clogging on the sieve screen.
Paul
>>
>
>
>
>
Bonnie Staffel on tue 1 jun 10
Patricia, you might be referring to the use of CMC as a glaze additive =3D
to
make it tough for handling. I use 1/4 of 1% CMC addition (.0025) =3D
dispersed
in one of the dry ingredients before adding to the water. This also
deflocculates my glaze so the ratio of water needs to be carefully =3D
checked.
This material gives me a hard finished dry glaze so that I can decorate =3D
on
top without having to fight a powdery surface that could come from =3D
handling.
Bonnie Staffel =3D20
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
DVD=3DA0 Throwing with Coils and Slabs
DVD=3DA0 Introduction to Wheel Work
Charter Member Potters Council
Bonnie Staffel on wed 2 jun 10
If you really want to mix up a wet batch of CMC, I used an electric =3D
blender
(specifically only for the studio) put in about one or two cups of very =3D
hot
water, then slowly add the CMC powder as the blender is whirring. You =3D
can
stop as soon as the mixture becomes the gum consistency. Really only =3D
takes
less than 1/4 of a cup of CMC. I then store it in a covered jar. My mix =3D
does
not mold, but your type may for whatever reason.=3D20
I guess you know that CMC is used in some foods and candies to have an
edible degree of hardness. Wonder if I have the food grade CMC?=3D20
Bonnie
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
DVD=3DA0 Throwing with Coils and Slabs
DVD=3DA0 Introduction to Wheel Work
Charter Member Potters Council
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