Jorge Nabel on mon 8 dec 03
I had experienced a similar problem. Fired a local adaptation of M6
variegated blue, and refired to
bisque temperature because of some blisters and it came out of the kiln
coffeandmilky satin brown.
I blamed the Carb. Cobalt as I used in a previous test CObalt Silicate and
happened the same,and was told
to use Cabonate instead.This is a very weak Spanish Carbonate that the
importer says is the best he could
buy,but the licorice came out brown with the 2%of it.....
The strange part is that after the first firing it come out fine,nice
blue...Can it be iron cristal growing????
Just another tought.
Jorge en Buenos Aires- Mercosur
Hi Michele,
This is hard to imagine what could be wrong - is it our varigated blue from
our book? you sure you put the copper and cobalt in?
I think the the floating blue comes out brown if on too thin.
Better do some tests and see if you have all the right materials in those
glazes.
RR
>I just fired my electric kiln to cone 6 using the Mastering ^6 firing
>schedule. My Variegated Blue, Glossy base came out a semi matte beige and
>my floating blue came out brown. Where has my blue gone? All my other
>glazes were great. I dipped the pots for 3 seconds and the glazes seem
>thick enough. Anyone have any ideas?
>
>Michele D'Amico
Ron Roy
Ron Roy on thu 11 dec 03
Hi Jorge and Michele,
I an beginning to wonder if the clay the ware is made out of is part of the
problem - would you both give me a brief description of the clays you are
using.
While it may be a material problem - it may also be compounded by other factors.
I would very much like to try and pin down the problem - with your help -
please - RR
>I had experienced a similar problem. Fired a local adaptation of M6
>variegated blue, and refired to
>bisque temperature because of some blisters and it came out of the kiln
>coffeandmilky satin brown.
>I blamed the Carb. Cobalt as I used in a previous test CObalt Silicate and
>happened the same,and was told
>to use Cabonate instead.This is a very weak Spanish Carbonate that the
>importer says is the best he could
> buy,but the licorice came out brown with the 2%of it.....
>The strange part is that after the first firing it come out fine,nice
>blue...Can it be iron cristal growing????
>
>Just another tought.
>Jorge en Buenos Aires- Mercosur
>
>
>
>
>
>
>
>Hi Michele,
>
>This is hard to imagine what could be wrong - is it our varigated blue from
>our book? you sure you put the copper and cobalt in?
>
>I think the the floating blue comes out brown if on too thin.
>
>Better do some tests and see if you have all the right materials in those
>glazes.
>
>RR
>
>>I just fired my electric kiln to cone 6 using the Mastering ^6 firing
>>schedule. My Variegated Blue, Glossy base came out a semi matte beige and
>>my floating blue came out brown. Where has my blue gone? All my other
>>glazes were great. I dipped the pots for 3 seconds and the glazes seem
>>thick enough. Anyone have any ideas?
>>
>>Michele D'Amico
>
>Ron Roy
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Liz Gowen on thu 11 dec 03
I had a similar experience, my nieces put the bright sky blue on 2 cups and
licorice. In the first firing having fired down per instructions in R&J's
book it came out as expected, deep black and very brilliant blue. I had used
a white liner that crawled in a couple of places. so dabbed with a clear on
those places and refired to ^04.
The licorice came out almost temoku brown black and the brilliant blue
came out much more mottled and more like the clear powder blue (but a bit
more slate like) in the book not at all the brilliant blue. I had 2 plates
they had done with the same glazes to compare them to after since they
weren't refired. I thought the refired were quite nice, more like reduction
pieces. I thought it was like the cobalt was separating more into the
crystals since it was in essence getting more soaking at the crystal growth
temp. ( like those that get blue crystals with a tan background) not at all
unpleasant. Nice to know if that blue comes out a bit too bright for a
project they can be refired to change them . I should have taken a picture
of the 2 before giving them to the girls so someone could put them up on a
temp website. These were made with standards 112 clay.
Liz Gowen
> I an beginning to wonder if the clay the ware is made out of is part of
the
> problem - would you both give me a brief description of the clays you are
> using.
>
> While it may be a material problem - it may also be compounded by other
factors.
>
> I would very much like to try and pin down the problem - with your help -
> please - RR
>
> >I had experienced a similar problem. Fired a local adaptation of M6
> >variegated blue, and refired to
> >bisque temperature because of some blisters and it came out of the kiln
> >coffeandmilky satin brown.
Chris Schafale on thu 11 dec 03
I'm pretty sure the blue-turning-brown phenom is a rutile thing. I had that
happen to me with Floating Blue. Refired to 06 in order to put a special
inscription on the back of a plate for a special order. Shocked me when I
opened the kiln and it was tan. The good news is, I refired to cone 5 and it
was perfectly blue again.
Chris
On 11 Dec 2003 at 7:38, Liz Gowen wrote:
> I had a similar experience, my nieces put the bright sky blue on 2 cups and
> licorice. In the first firing having fired down per instructions in R&J's
> book it came out as expected, deep black and very brilliant blue. I had used
> a white liner that crawled in a couple of places. so dabbed with a clear on
> those places and refired to ^04.
> The licorice came out almost temoku brown black and the brilliant blue
> came out much more mottled and more like the clear powder blue (but a bit
> more slate like) in the book not at all the brilliant blue. I had 2 plates
> they had done with the same glazes to compare them to after since they
> weren't refired. I thought the refired were quite nice, more like reduction
> pieces. I thought it was like the cobalt was separating more into the
> crystals since it was in essence getting more soaking at the crystal growth
> temp. ( like those that get blue crystals with a tan background) not at all
> unpleasant. Nice to know if that blue comes out a bit too bright for a
> project they can be refired to change them . I should have taken a picture
> of the 2 before giving them to the girls so someone could put them up on a
> temp website. These were made with standards 112 clay.
> Liz Gowen
>
> > I an beginning to wonder if the clay the ware is made out of is part of
> the
> > problem - would you both give me a brief description of the clays you are
> > using.
> >
> > While it may be a material problem - it may also be compounded by other
> factors.
> >
> > I would very much like to try and pin down the problem - with your help -
> > please - RR
> >
> > >I had experienced a similar problem. Fired a local adaptation of M6
> > >variegated blue, and refired to
> > >bisque temperature because of some blisters and it came out of the kiln
> > >coffeandmilky satin brown.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
Michele D'Amico on fri 12 dec 03
Ron,
I used three different clays and had the same problem. Cone 5 B Mix, a
Cone 4-10 red clay, (maybe cinnamon) and Danish which is really a cone 10
clay. When I mixed a 100 grams for a test the results were fine. I had
the problem with the large batch. Same clays same firing schedule. I'm
pretty certain I mixed things right.
Michele
damicom@cruzio.com
Ron Roy on sun 14 dec 03
Hi Liz,
Thanks for posting this - I think you are exactly right - crystals have
more time to grow at about bisque temperatures.
I should qualify that - if the glaze is a low fire glaze or is unbalanced
in that there is more fluxing material than necessary - the glaze may begin
to melt the crystals at cone 04 - in that case the crystal growth would
have to start over.
If that were the case then a refire at cone 08 or 06 might be better.
Am I waiting in vain for someone to do the experiments that will tell us
what is the best temperature for growing crystals in some specific glazes?
It's not that hard to do - fire several glazed tiles of each glaze to glaze
temp - then in subsequent lower firings - fire one tile of each glaze to
say cone 02 - hold for 1 hour and cool normally.
Fire another set to cone 04 - hold for an hour and cool normally.
Fire another set to cone 06 -
another to 08
Which firing resulted in the most recrystallization?
The more varied the glazes the more the results will vary but we will be
able to draw some conclusions from the molecular formulas of the different
glazes. I'll be glad to help if I'm needed.
RR
>I had a similar experience, my nieces put the bright sky blue on 2 cups and
>licorice. In the first firing having fired down per instructions in R&J's
>book it came out as expected, deep black and very brilliant blue. I had used
>a white liner that crawled in a couple of places. so dabbed with a clear on
>those places and refired to ^04.
> The licorice came out almost temoku brown black and the brilliant blue
>came out much more mottled and more like the clear powder blue (but a bit
>more slate like) in the book not at all the brilliant blue. I had 2 plates
>they had done with the same glazes to compare them to after since they
>weren't refired. I thought the refired were quite nice, more like reduction
>pieces. I thought it was like the cobalt was separating more into the
>crystals since it was in essence getting more soaking at the crystal growth
>temp. ( like those that get blue crystals with a tan background) not at all
>unpleasant. Nice to know if that blue comes out a bit too bright for a
>project they can be refired to change them . I should have taken a picture
>of the 2 before giving them to the girls so someone could put them up on a
>temp website. These were made with standards 112 clay.
> Liz Gowen
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Fara Shimbo on mon 15 dec 03
Ron Roy wrote:
> Am I waiting in vain for someone to do the experiments that will tell us
> what is the best temperature for growing crystals in some specific
glazes?
No, you're not. I've been doing just that with my own glazes for
a year or so. The information will be in the next edition of
Crystal Glazes. I've only worked so far with the glazes I use
myself and found that there is a lop-sided bell curve that arises
when you plot speed of growth in millimeters per 10 minutes against
soak temperature, and that it's different for each recipe.
Fa
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