Nancy Braches on thu 28 sep 06
Hi everyone
I made a test batch of floating blue and it did exactly what it was supposed to...break green on the rims and a nice blue.
Then I went and made a slightly larger batch (only 10 lbs). I have fired it 3 times and my floating blue is more a floating green and not a pretty green at that. Of course the places I threw honey (or as I call it, Runny Hunny) on the bowl I get the most gorgeous blue but the underlying floating green is uck!
Can anyone who knows the floating blue tell me why I'm getting green instead of blue. I used the recipe in the archives which matches the recipe in the clay times floating blue article from a while ago.
Thanks in advance. I can post a picture of bowl in myyahoo picture if anyone is interested in seeing it.
BTW....thanks to all who helped with my blue glaze..what's missing? I added 1 tsp of cobalt carbonate to my 1lb sample and have a nice medium blue that covers well.
Nancy
Hilltop Pottery
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Don Goodrich on thu 28 sep 06
Hi Nancy,
Sorry to see that Floating Blue has claimed yet another victim.
You're in good company on this list, and I'm sure there'll be
several suggestions.
My suggestion is that the greenish areas (lovingly referred to
as "snot green" by many) are where the glaze is thinner. When this
happens to me, I heat the pot in the oven to around 150 deg F,
or whatever the lowest setting on the oven is. Then I brush more
FB on the offending areas while hot, so it has a chance of drying
before it runs off. Try to apply the glaze evenly but thickly.
If you're lucky the next firing will be fine. Sometimes this glaze
will be darker if you refire it to ^5 instead of ^6.
Another alternative is to refire at a much lower temperature,
say ^04. At this temp, Floating Blue changes to a grey-green celadon color,
and you can tell everyone it was supposed to be that way.
Good luck,
Don Goodrich in chilly Zion, Illinois
goodrichdn@aol.com
Sue Cline on thu 28 sep 06
Nancy - I think the discussion in the past has revealed that Floating Blue does well, and what it's supposed to do, at ^5 to ^6, and with a "normal" or "fast" cool. If you slow down the cooling, a la Mastering Cone 6 Glazes by Ron Roy and John Hesselberth, the Floating Blue comes out sort of a snot green.
I use Floating Blue and generally fire a whole kiln load of it at ^5 without a controlled colldown, and then it is quite dependable (also dependably runny if it's too thick). For many of my other glazes I want a controlled cooldown and FB just doesn't work with that.
Sue Cline
Cincinnati, OH
Potters' Council Member
-----Original Message-----
>From: Nancy Braches
>Sent: Sep 28, 2006 2:43 PM
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Floating Blue --- again I know
>
>Hi everyone
>
>I made a test batch of floating blue and it did exactly what it was supposed to...break green on the rims and a nice blue.
>
>Then I went and made a slightly larger batch (only 10 lbs). I have fired it 3 times and my floating blue is more a floating green and not a pretty green at that. Of course the places I threw honey (or as I call it, Runny Hunny) on the bowl I get the most gorgeous blue but the underlying floating green is uck!
>
>Can anyone who knows the floating blue tell me why I'm getting green instead of blue. I used the recipe in the archives which matches the recipe in the clay times floating blue article from a while ago.
>
>Thanks in advance. I can post a picture of bowl in myyahoo picture if anyone is interested in seeing it.
>
>BTW....thanks to all who helped with my blue glaze..what's missing? I added 1 tsp of cobalt carbonate to my 1lb sample and have a nice medium blue that covers well.
>
>Nancy
>Hilltop Pottery
>
>
>---------------------------------
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> Get on board. You're invited to try the new Yahoo! Mail.
>
>______________________________________________________________________________
>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/
>
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John Rodgers on thu 28 sep 06
Hi Nancy.
Floating Blue is my principle glaze. I have been using it a long time,
and it is rare that I have problems with it. Doesn't mean I never have
problems, but nowadays it's a rare occasion when it happens.
The first time I tried it I was pushed for a show, had a new kiln - new
to me, anyway, and the whole load came out "snot green". I was
mortified. The stuff ran all over the place, stuck pots to the shelves,
made a mess. Needless to say, I didn't make the show, either.
Now, after many firings, I have it pretty well under control. The glaze
is finicky, but if you stay on top of the numbers with the glaze, it
will work every time. On FB, I weigh everything out exactly by the
numbers. I use only distilled water. I adjust the density to exactly
1.3. I use Cone 5 B-mix bisqued to 06. I dip and hold the bisque
submerged exactly 15 seconds. I fire to cone 5 (free standing witness
cone bent to 3 oclock). If I spray, it gets 10 full coats. I fire fast
with a fast cool down. The results have been consistent and excellent.
Beautiful with brown highlights on edges. And it virtually never runs,
except when I deliberately fire it a bit hotter.
I would like to see the recipe you use, and compare it to mine, because
my rims are brown. I am curious about the green you get on the rims and
edges.
Regards,
John Rodgers
Chelsea, AL
Nancy Braches wrote:
> Hi everyone
>
> I made a test batch of floating blue and it did exactly what it was supposed to...break green on the rims and a nice blue.
>
> Then I went and made a slightly larger batch (only 10 lbs). I have fired it 3 times and my floating blue is more a floating green and not a pretty green at that. Of course the places I threw honey (or as I call it, Runny Hunny) on the bowl I get the most gorgeous blue but the underlying floating green is uck!
>
> Can anyone who knows the floating blue tell me why I'm getting green instead of blue. I used the recipe in the archives which matches the recipe in the clay times floating blue article from a while ago.
>
> Thanks in advance. I can post a picture of bowl in myyahoo picture if anyone is interested in seeing it.
>
> BTW....thanks to all who helped with my blue glaze..what's missing? I added 1 tsp of cobalt carbonate to my 1lb sample and have a nice medium blue that covers well.
>
> Nancy
> Hilltop Pottery
>
>
> ---------------------------------
> Do you Yahoo!?
> Get on board. You're invited to try the new Yahoo! Mail.
>
> ______________________________________________________________________________
> 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.
>
>
>
Gary Harvey on thu 28 sep 06
floating blue is a cone 5 glaze and do not soak it, just let the kiln go
off and let it cool naturally. (no cool down) Gary Harvey, Palestine TX
----- Original Message -----
From: "Nancy Braches"
To:
Sent: Thursday, September 28, 2006 1:43 PM
Subject: Floating Blue --- again I know
> Hi everyone
>
> I made a test batch of floating blue and it did exactly what it was
> supposed to...break green on the rims and a nice blue.
>
> Then I went and made a slightly larger batch (only 10 lbs). I have fired
> it 3 times and my floating blue is more a floating green and not a pretty
> green at that. Of course the places I threw honey (or as I call it, Runny
> Hunny) on the bowl I get the most gorgeous blue but the underlying
> floating green is uck!
>
> Can anyone who knows the floating blue tell me why I'm getting green
> instead of blue. I used the recipe in the archives which matches the
> recipe in the clay times floating blue article from a while ago.
>
> Thanks in advance. I can post a picture of bowl in myyahoo picture if
> anyone is interested in seeing it.
>
> BTW....thanks to all who helped with my blue glaze..what's missing? I
> added 1 tsp of cobalt carbonate to my 1lb sample and have a nice medium
> blue that covers well.
>
> Nancy
> Hilltop Pottery
>
>
> ---------------------------------
> Do you Yahoo!?
> Get on board. You're invited to try the new Yahoo! Mail.
>
> ______________________________________________________________________________
> 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.
>
Steve Slatin on fri 29 sep 06
Nancy --
A few possibilities --
1 - the Gerstley may be an issue -- if you got it from a
different bag or something, Gerstley is so variable that
it could have been responsible for the change.
2 - Rutile is also variable, though if you got it from the
same supplier it's probably pretty similar.
3 - Clay body differences can be incredibly significant.
If you used a different clay, that might have done it.
4 - Of the colorants, cobalt is the most powerful. It's
possible that you got a bad weight from your scale
and that more cobalt will help (I'd be interested in
your results) but I suspect your 'snot green' color
comes from a mixture of blue and yellow. The yellow
may come from iron in the clay body, iron in the RIO,
the titanium in the rutile, and so on.
The Chappell version is notorious for going green
if overfired. I do not know why this is, but it's a
very sodium rich glaze, and those glazes sometimes
are 'tippy' -- evincing strong color change with slight
differences in formulation or firing. I like the
Chappell effects myself, but because I didn't want
to mess with Gerstley I used a different recipe myself.
Good luck -- please tell us if the extra cobalt
changed anything -- Steve S
Nancy Braches wrote:
Hi Steve
I am using the chappell version which is
Nephaline 47.3
Gerstly 27
Flint 20.3
EPK 5.4
Cobalt Oxide1.0
Red Iron Oxide2.0
Rutile 4.0
Bentonite 1.0
My test making 1lb of the glaze was perfect, I even tried 3 of the variations from the clay times article on floating blue. They all were what I expected. I then mixed a batch of 10 lbs and this batch is giving me problems. I used
4.7 lbs of Nephaline
2.7 lbs of gertsley
2.0 lbs of flint
.6 lbs of EPK
.1 lbs cobalt oxide
.2 lbs red iron oxide
.4 lbs of rutile
.1 lbs of bentonite
I have an electronic mailing scale that makes it easy to measure for smaller batches but this 10 lb batch looks nothing like my original test tile. I measured out 16oz of this and added .25% of cobalt oxide to it. I am going to test it when I fire a glaze tonight and see if that helps...I hate to throw out this glaze and start again. I fired last time to cone 6. Top shelf hit cone 6 and the piece on top, while smooth and shiny...was awful green. The bottom shelf which is about cone 5 1/2...the piece that came out of there was pinholed and rough. All other pieces in the kiln without floating blue...were fine.
Thanks for any input
Nancy
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Chic Lotz + keith Montgomery on fri 29 sep 06
Nancy,
I found that when the floating blue overfires, it tends more towards
green.
Chic Lotz
Grass Valley, CA
Steve Slatin on fri 29 sep 06
Nancy --
Everyone's trying to be helpful, but what'd be most helpful would be if
you let us know what you're doing.
"Floating Blue" isn't a single glaze. It's many glazes with a specific
effect. (I have used 3 myself.) The James Chapell version uses
Nepheline Syenite, Gerstley Borate, Silica, EPK, and some RIO.
The DigitalFire site gives a version with Alberta Slip, and Frit 3134.
Ron Roy has many variation, some using Frit 3278. The list goes
on ...
Some variations of recipes have the "snot green" tendency; others
either don't or it hasn't been reported about them. If you use them
quite a bit, you get comfortable with substititions and so on.
Firing to ^5 seems to be a solution for some of the problems;
applying the glaze "thick enough" seems to be the solution for
others.
And, as always, the clay you're firing over makes a huge difference.
So ... what version of the recipe do you use, and what clay do you
fire over, and to what cone with what kind of firing (i.e., controlled
cooling or no, a fast or a slow firing)?
Best wishes -- Steve Slatin
Nancy Braches wrote:
Hi everyone
I made a test batch of floating blue and it did exactly what it was supposed to...break green on the rims and a nice blue.
Then I went and made a slightly larger batch (only 10 lbs). I have fired it 3 times and my floating blue is more a floating green and not a pretty green at that. Of course the places I threw honey (or as I call it, Runny Hunny) on the bowl I get the most gorgeous blue but the underlying floating green is uck!
---------------------------------
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Nancy Braches on fri 29 sep 06
I am going to try this again at cone 5 but at cone 5 1/2 (which is the bottom shelf on my skutt kiln) the piece I had in my last batch still had a lot of green in it but there was blue also but I found a lot of pinholing in that piece, almost like the glaze didn't get hot enough.
I am preparing to fire again tonight in the skutt and using my cone 5 glazes to see if this helps.
Thanks again for all the help
Nancy
Hilltoppottery
Chic Lotz + keith Montgomery wrote: Nancy,
I found that when the floating blue overfires, it tends more towards
green.
Chic Lotz
Grass Valley, CA
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Nancy Braches on fri 29 sep 06
Hi Steve
I am using the chappell version which is
Nephaline 47.3
Gerstly 27
Flint 20.3
EPK 5.4
Cobalt Oxide1.0
Red Iron Oxide2.0
Rutile 4.0
Bentonite 1.0
My test making 1lb of the glaze was perfect, I even tried 3 of the variations from the clay times article on floating blue. They all were what I expected. I then mixed a batch of 10 lbs and this batch is giving me problems. I used
4.7 lbs of Nephaline
2.7 lbs of gertsley
2.0 lbs of flint
.6 lbs of EPK
.1 lbs cobalt oxide
.2 lbs red iron oxide
.4 lbs of rutile
.1 lbs of bentonite
I have an electronic mailing scale that makes it easy to measure for smaller batches but this 10 lb batch looks nothing like my original test tile. I measured out 16oz of this and added .25% of cobalt oxide to it. I am going to test it when I fire a glaze tonight and see if that helps...I hate to throw out this glaze and start again. I fired last time to cone 6. Top shelf hit cone 6 and the piece on top, while smooth and shiny...was awful green. The bottom shelf which is about cone 5 1/2...the piece that came out of there was pinholed and rough. All other pieces in the kiln without floating blue...were fine.
Thanks for any input
Nancy
Hilltop Pottery
Steve Slatin wrote: Nancy --
Everyone's trying to be helpful, but what'd be most helpful would be if
you let us know what you're doing.
"Floating Blue" isn't a single glaze. It's many glazes with a specific
effect. (I have used 3 myself.) The James Chapell version uses
Nepheline Syenite, Gerstley Borate, Silica, EPK, and some RIO.
The DigitalFire site gives a version with Alberta Slip, and Frit 3134.
Ron Roy has many variation, some using Frit 3278. The list goes
on ...
Some variations of recipes have the "snot green" tendency; others
either don't or it hasn't been reported about them. If you use them
quite a bit, you get comfortable with substititions and so on.
Firing to ^5 seems to be a solution for some of the problems;
applying the glaze "thick enough" seems to be the solution for
others.
And, as always, the clay you're firing over makes a huge difference.
So ... what version of the recipe do you use, and what clay do you
fire over, and to what cone with what kind of firing (i.e., controlled
cooling or no, a fast or a slow firing)?
Best wishes -- Steve Slatin
Nancy Braches wrote:
Hi everyone
I made a test batch of floating blue and it did exactly what it was supposed to...break green on the rims and a nice blue.
Then I went and made a slightly larger batch (only 10 lbs). I have fired it 3 times and my floating blue is more a floating green and not a pretty green at that. Of course the places I threw honey (or as I call it, Runny Hunny) on the bowl I get the most gorgeous blue but the underlying floating green is uck!
---------------------------------
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______________________________________________________________________________
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.
---------------------------------
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Don Goodrich on fri 29 sep 06
Hi Nancy,
You may be on the right track in refiring to ^5, but I don't know if it
will help the pinholing problem. Pinholes might be preventable with a
hotter bisque. As you imply in your post, higher glaze firing may fix them.
OTOH hotter firing may bring some crawling, so it's a bit of a balancing
act. One thing that I haven't noticed in the present discussion is what
clay you're using. Too late to change that now, I realize, but it gives
some indication of the cause of undesired color.
A post by Michael Banks about 7 years ago made some sense of this:
http://tinyurl.com/g2y04
In this post, he explains that the titanium dioxide in the rutile yanks
iron out of nearby sources (the clay or glaze) making various other colors.
The time during which it can do this is limited by the cooling rate.
When I used mostly stoneware I saw the greenish FB color in thin areas
more often. Now that I use mostly porcelain, the thin areas tend toward
just lighter blue, with a hint of brown. Something complex is happening
in this glaze. Areas of thin glaze may allow more of the rutile/iron
interaction to show up, while thicker areas may show more coloration
from the cobalt. Firing lower gives the titanium less melt time, hence
it can't rob as much iron from the clay body. Firing hotter and cooling
slower give the melt more time to flow as the titanium color develops.
This means more visual texture (hare's fur) from a hotter than from a
cooler firing, especially on vertical surfaces. Slow cooling also gives
titanium dioxide crystals (white if pure) more time to form, so you'd
probably get an overall lighter blue with slow cooling. I know I do.
Hope this makes sense.
Don Goodrich
whose own early inquiries about Floating Blue can be seen here:
http://tinyurl.com/qx2jw
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