Veena Raghavan on sun 25 apr 99
Hello Clayarters,
I wonder if someone can help with this problem, and if they have
had the same bad experience.
Ceramic Supply in Lodi New Jersey has a red iron oxide, they call
special red iron oxide. I bought some some years ago, and it has
consistently produced great iron red color. The studio where I do my
pottery also buys their iron oxide from them, and the oxide was fine,
including a batch they bought some time ago. Then, about a month or so ago,
they and I bought the Special from them. The studio's Randy's Red is coming
out brown with hardly any red at all, and my reds are doing the same.
I wonder if anyone else gets their red iron supply from the same
source and if they have had the same problem, and if so, what did you do
about it.
I also wonder whether our wonderful glaze gurus have some solution.
Is there anything one can add to the glaze mix to compensate for the fact
that the oxide (probably obtained from a different source than their
previous one) is not producing reds?
This type of glaze is one of the basics I depend on, so it is
really upsetting.
Any help would greatly appreciated, in fact, a solution would be a
life saver.
Thank you in advance.
Veena Raghavan
75124.2520@compuserve.com
Paul Lewing on mon 26 apr 99
Hi, Veena,
I've done hundreds of tests on oxidation iron reds, and my experience is
that the redder the iron is before it's fired, the redder it will be
after. Not a big help when you're mail-ordering, I realize, but maybe
you can call and ask them about the color.
Those who were at my slide presentation at NCECA know that I've
abandoned those high-calcium, high SiO2:Al2O3 ratio iron reds in favor
of a new recipe. Just too unpredictable. Unfortunately, folks, I won't
post that to Clayart, because one of the reasons I call it Drop Dead Red
is that is has LOTS of lead in it. Sorry. Sure is pretty, though.
Paul Lewing, Seattle
Lois Ruben Aronow on mon 26 apr 99
------------------
ME=21 ME=21 ME=21=21=21 I made up a 6000 bucket. tested it 3 times. =
dumped
it. Made up a new bucket. Looked OK. Tested it 3 times. This batch
is so wildly inconsistent. Depends on application AND which (of 3)
kiln it's fired in. And where. I mention this because this is a
longtime VERY reliable glaze. It's hard to screw it up, even for
beginners.
I even called Ceramic Supply to try and figure out if they sent me
Spanish Red (which is for clay) instead of special (which is for
glaze).
I am so relieved to hear someone mention this, as I am the glaze
chemist for our studio, and people are pointing their fingers at me
for this. Thanks for letting me know I'm not going insane. The
second time I mixed the Randy's with the new batch of RIO, I had
someone watch/help me, to make sure I was measuring correctly and
wasn't flipping out. I have to say, I don't often screw up the studio
glazes, especially large batches. I thought I lost my mind.
big sigh of relief. Still, don't know what to do about it.
On Sun, 25 Apr 1999 10:00:10 EDT, Veena Raghavan wrote:
=3E Ceramic Supply in Lodi New Jersey has a red iron oxide, they call
=3Especial red iron oxide. I bought some some years ago, and it has
=3Econsistently produced great iron red color. The studio where I do my
=3Epottery also buys their iron oxide from them, and the oxide was fine,
=3Eincluding a batch they bought some time ago. Then, about a month or so =
ago,
=3Ethey and I bought the Special from them. The studio's Randy's Red is =
coming
=3Eout brown with hardly any red at all, and my reds are doing the same.
=3E I wonder if anyone else gets their red iron supply from the same
=3Esource and if they have had the same problem, and if so, what did you do
=3Eabout it.
=3E I also wonder whether our wonderful glaze gurus have some =
solution.
=3EIs there anything one can add to the glaze mix to compensate for the fact
=3Ethat the oxide (probably obtained from a different source than their
=3Eprevious one) is not producing reds?
=3E This type of glaze is one of the basics I depend on, so it is
=3Ereally upsetting.
=3E Any help would greatly appreciated, in fact, a solution would be =
a
=3Elife saver.
=3EThank you in advance.
=3E
=3EVeena Raghavan
=3E75124.2520=40compuserve.com
Susan Fox on tue 27 apr 99
Veena - I use Randy's also - I have two kilns, and the glaze is brown in
one and red in the other - the thickness of application makes a big
difference, too. I mean, it may not be the iron oxide, but subtle
changes in the firing temp or atmosphere in your kiln. Kilns do change
gradually . I love this glaze for its quirkiness but sometimes it does
disappoint. Good luck.-
Susan
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Ron Roy on wed 28 apr 99
Hi Veena,
First thing to try is vary the iron - do this - make up 5 test batches -
500 grams each - I don't know how much iron is in the recipe now but lets
say its 9% - so a test with 8, 8.5,9.5 and 10 - and remember - the slower
the cooling the better the red should be. You can also refire them to
bisque temp to give the iron more chance to recrystallize.
RR
>----------------------------Original message----------------------------
>------------------
>ME! ME! ME!!! I made up a 6000 bucket. tested it 3 times. dumped
>it. Made up a new bucket. Looked OK. Tested it 3 times. This batch
>is so wildly inconsistent. Depends on application AND which (of 3)
>kiln it's fired in. And where. I mention this because this is a
>longtime VERY reliable glaze. It's hard to screw it up, even for
>beginners.
>
>I even called Ceramic Supply to try and figure out if they sent me
>Spanish Red (which is for clay) instead of special (which is for
>glaze).
>
>I am so relieved to hear someone mention this, as I am the glaze
>chemist for our studio, and people are pointing their fingers at me
>for this. Thanks for letting me know I'm not going insane. The
>second time I mixed the Randy's with the new batch of RIO, I had
>someone watch/help me, to make sure I was measuring correctly and
>wasn't flipping out. I have to say, I don't often screw up the studio
>glazes, especially large batches. I thought I lost my mind.
>
>big sigh of relief. Still, don't know what to do about it.
>
>On Sun, 25 Apr 1999 10:00:10 EDT, Veena Raghavan wrote:
>
>> Ceramic Supply in Lodi New Jersey has a red iron oxide, they call
>>special red iron oxide. I bought some some years ago, and it has
>>consistently produced great iron red color. The studio where I do my
>>pottery also buys their iron oxide from them, and the oxide was fine,
>>including a batch they bought some time ago. Then, about a month or so ago,
>>they and I bought the Special from them. The studio's Randy's Red is coming
>>out brown with hardly any red at all, and my reds are doing the same.
>> I wonder if anyone else gets their red iron supply from the same
>>source and if they have had the same problem, and if so, what did you do
>>about it.
>> I also wonder whether our wonderful glaze gurus have some solution.
>>Is there anything one can add to the glaze mix to compensate for the fact
>>that the oxide (probably obtained from a different source than their
>>previous one) is not producing reds?
>> This type of glaze is one of the basics I depend on, so it is
>>really upsetting.
>> Any help would greatly appreciated, in fact, a solution would be a
>>life saver.
>>Thank you in advance.
>>
>>Veena Raghavan
>>75124.2520@compuserve.com
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
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