jonpjon@ibm.net on mon 25 mar 96
David Stuchbery mentioned in his response to "request for Copper reds"
that the red tends to burn out if overfired. I have found this to be the
biggest problem about this glaze.I have also noticed that prolonged
firings seem to cause this also.
The first kiln I ever built was a small insulation brick catenary that
fired to ^9 in 12 hrs. or less and cooled overnight, I had some nice
reds from it. My current kiln is an 80cu.ft. hardbrick with 1in. of
kaowool behind the firebricks, and a red brick exterior. I wouldn`t
build another like this as my firings are usually around 16hrs. and,
whats worse , take 2 days to cool! I have observed that it takes
8 hrs.or so just to cool down to below red heat. I have noticed that
there are some glazes that long firings tend to favor, unfortunately
copper red is not one of them. More often than not the color dissappears
leaving a white with fleeting flecks of red.
One solution I have heard is to use a thin second coat of transparent
glaze to keep the copper from volatalizing, I haven`t had much
success with this either.
Does anyone have any experience with this problem? Does the
form of copper make any difference? Oxide,carbonate.cupric or cuprous?
Can copper loss be compensated by increasing the amount or some other
method? Is it just a matter of adjusting the melt?
Thanks Jon Pettyjohn, Manila jonpjon@ibm.net
John Britt on tue 26 mar 96
My experience with copper red is that what matters most is to begin
reduction at cone 012 fairly heavy and then go into moderate reduction after
cone 05 drops. Continue moderate to light reduction until cone 10 then a
brief oxidation peroid of about 10 minutes.
If you over reduce it will be liver brown and under reduced will be celadon.
One solution to a problem (uneven, spotty reduction and under reduced)we had
was to turn down the gas and air. To slow it down and reduce at the above
schedule. We were firing in an Alpine updraft with blowers and just running
the same schedule as the people who fired before us. (It was a community
center). They were firing at 4 pounds pressure (natural gas) with the
blowers at 70. Something like that. But we reduced the gas and the air and
the firing was 100% better. No more spotty reduction or unreduced pots. (I
kind of miss those unwanted interesting results though.)
Anyway try:
Pete 's Cranberry Red Cone 10
Gerstley Borate 10.2g
Whiting 11.1g
Custer Feldspar 73.8g
Flint 4.9g
Copper Carbonate 0.3g
Tin Oxide 1.0g
Copper Red I - Cone 10
Custer Feldspar 42.4g
Whiting 12.0g
Flint 13.6g
Ferro 3110 8.0g
Zinc Oxide 4.0g
Talc 3.2g
Kaolin 4.8g
Tin Oxide 1.2g
Copper Carbonate 0.8g
Splotchy Lavender Glaze - Cone 10 Comments:
Barium Carbonate 2.0g
Calcined Zinc Oxide 4.0g
Lithium Carbonate 2.0g GREAT BLUE/RED /DARK BLUE!
Whiting 14.0g
Custer Feldspar 50.0g
Frit 14 (3134) 7.0g
Bentonite 1.0g
Flint (325 mesh) 20.0g
Tin Oxide 1.0g
Copper Carbonate 0.6g
Semi Matt Red - Cone 10
Calcined Zinc Oxide 6.5g
Whiting 13.0g
Frit 14 (3134) 9.0g White
G-2 Feldspar 39.0g RETRY
Ball Clay 7.5g
Flint 25.0g
Tin Oxide 9.0g
Copper Carbonate 0.4g
Dependable Red - Cone 10
Calcined Zinc Oxide 4.5g
Talc 3.5g Oxblood needs to be thick mp.
Whiting 13.0g
Frit 14 (3134) 10.8g
Kona F-4 Feldspar 45.5g
Bentonite 1.5g
EPK 5.2g
Flint 16.0g
Tin Oxide 1.0g
Copper Carbonate 0.7g
Hope you enjoy.
check out the glaze section on my home page. I am updating it with lots of
glazes in the next week or so.
Later on,
John Britt
Dysfunctional Pottery
claydude@erinet.com
http://www.erinet.com/claydude/britt1.html
Bill Buckner on tue 26 mar 96
Jon:
Copper is, indeed, votatile in glazes at the cone 8-10 range. If you
feel the slow cool is affecting you copper reds negatively, you might try
forced cooling several hundred degrees at the end of the fire. Leaving
the secondary air and the damper open after the burners are shut down
should be sufficient (use a pyrometer to monitor). If that is not
enough, try leaving the blowers on (assuming forced draft) as well
(burners off).
-Bill
Bill Buckner e-mail: bbuckner@gsu.edu
Georgia State University http://www.gsu.edu/~couwbb
peter pinnell on tue 26 mar 96
Hi David,
From my experience, a slow cooling actually helps copper reds, making
them deeper and more transparent. The huge kilns that the Chinese used
to produce copper reds during the Ching Dynasty took WEEKS to cool, not
days.
I would guess that the reason you're not getting red is that either you
are not beginning your reduction soon enough, or there is too thin a
glaze application. Either of these can result in the result you described.
Firing and application requirements vary depending on the formula of the
glaze, but generally I would say that reduction should begin by about
Orton cone 012. This is quite a bit earlier than is required by most
glazes, but that is because these high alkalie, low alumina formulas
begin to flux at a much earlier point.Once these glazes melt, they are
hard to reduce. The spaces in the glaze matrix are just too small for
the reduction molecules to penetrate, kind of like trying to push
basketballs through a screen door.
During the firing, a copper red separates into several distinct layers.
Between the body and the glaze a layer of anorthite and wollastonite
crystals grow that provide a white backround for the glaze. Above that
is a red layer that is made up of a liquid/liquid phase seperation:
globules of red glass floating in a transparent glaze. Above it all is a
thin, clear layer. If the glaze is applied too thinly, the first layer to
go is the red one. It is possible to produce even more layers by adding
a small amount of zinc, which adds tiny orange flects, and titania, which
pushes the glaze towards blue.
Are you using the same kind of burners that you used before? Are you
measuring reduction? It could just be that you are not getting as much
reduction as you think.
Good luck.
Pete Pinnell
P.S. I had the best luck with copper carbonate, in a ration of one to
three with tin oxide. ( .33 % copper carb to 1.0% tin oxide)
On Mon, 25 Mar
1996 jonpjon@ibm.net wrote:
> ----------------------------Original message----------------------------
> David Stuchbery mentioned in his response to "request for Copper reds"
> that the red tends to burn out if overfired. I have found this to be the
> biggest problem about this glaze.I have also noticed that prolonged
> firings seem to cause this also.
> The first kiln I ever built was a small insulation brick catenary that
> fired to ^9 in 12 hrs. or less and cooled overnight, I had some nice
> reds from it. My current kiln is an 80cu.ft. hardbrick with 1in. of
> kaowool behind the firebricks, and a red brick exterior. I wouldn`t
> build another like this as my firings are usually around 16hrs. and,
> whats worse , take 2 days to cool! I have observed that it takes
> 8 hrs.or so just to cool down to below red heat. I have noticed that
> there are some glazes that long firings tend to favor, unfortunately
> copper red is not one of them. More often than not the color dissappears
> leaving a white with fleeting flecks of red.
> One solution I have heard is to use a thin second coat of transparent
> glaze to keep the copper from volatalizing, I haven`t had much
> success with this either.
> Does anyone have any experience with this problem? Does the
> form of copper make any difference? Oxide,carbonate.cupric or cuprous?
> Can copper loss be compensated by increasing the amount or some other
> method? Is it just a matter of adjusting the melt?
> Thanks Jon Pettyjohn, Manila jonpjon@ibm.net
>
grevans@cencom.net on sat 22 jun 96
Just finishing up the arch on our reduction kiln at UIS. Looking for copper
red and Barium Matt glazes.
Greg Evans
CFisher995@aol.com on mon 2 sep 96
We're looking for a good copper red at the studio where I work. We used to
have a copper red that was Toshika's. It was given to the owner of the studio
years ago. Someone walked off with the recipe. We are looking for a cone 10
Reduction Copper Red. We need a copper red with silicon carbide for local
reduction.
We just tested about 5 copper reds. Only on came close but it was very runny.
Can anybody help?
Shrope/Ratcliffe on tue 3 sep 96
Here's 2 recipies: for c10
Buckspar 48
Whiting 3
Colemanite 5
Dolomite 10
Zinc 2
EPK 2
Flint 30
add:
Colemanite 10%
Tin 3%
Copper Carb. 1.2%
(optional)
Colbalt Carb 2 gms. for purple
(Vivika and Otto)
Custer spar 43.2
EPK 1.9
Flint 28
Whiting 2.7
Colemanite 9
Dolomite 9
Zinc 1.7
Barium 4.5
add:
Tin 2.75%
Copper Carb. 3%
(unknown origin)
Both are good stable glazes and need heavy final reduction.
You can push them to c11.
Sorry, no silicon carbide, but experimenting is always an option.
Regards,
Peter
http://charm.net/~pssr/
Wendy Hampton on tue 21 jan 97
Hi,
Does anyone know of a copper red that can be accomplished in oxidation at
Cone 5-6?
thanks,
Wendy
Angela Young on sat 24 jul 99
Does anyone have recipe for Copper Red ^10 glaze?
It would be greatly appreciated.
thanks, angie from Tampa
David Hendley on tue 27 jul 99
At 04:15 PM 7/24/99 EDT, you wrote:
>----------------------------Original message----------------------------
>Does anyone have recipe for Copper Red ^10 glaze?
>It would be greatly appreciated.
>thanks, angie from Tampa
>
Kiln firing technique is the most important variable for producing
good copper red glazes. No recipe will work if the kiln is not
fired properly. I recommend oxidation from start to about cone
010, heavy reduction from 010 to about cone 1, and moderate
reduction from cone 1 to cone 10.
Simply Red, cone 10 reduction
recipe
45 Custer feldspar
9 Gerstley Borate
12 whiting
6 talc
3 EPK
2.5 bentonite
22.5 flint
2 tin oxide
.8 copper carbonate
unity formula
.54 Ca0
.19 Mg0
.26 KNa0
.12 Ba203
.32 Al203
3.42 Si0
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
DONALD G. GOLDSOBEL on tue 27 jul 99
Bob<
When you blow in the copper, is it into a kiln loaded with only clear chun
glazes? Could you be a bit more detailed. The idea is very appealing
Thank you Donald Goldsobel in the San Fernando Valley where we have unseasonalal cool
humid weather. A blessing after 90+ heat.
>----------------------------Original message----------------------------
>Dear Angela,
> Here are two glazes by Harriet Brisson.
>Feldspar 261-F 41.7
>Kaolin 1.7
>Flint 26.1
>Whiting 7.0
>Gerstley Borate 8.7
>Dolomite 8.7
>Zinc Oxide 6.1
>Tin Oxide 2.1
>Copper Carbonate 0.45
>
>Second Glaze:-
>Nepheline Syenite 42.4
>Feldspar 261-F 9.1
>Kaolin 2.0
>Flint 22.7
>Gerstley Borate 13.2
>Whiting 10.6
>Copper Carbonate 0.3
>Tin Oxide 1.0
>Both glazes worked for me with heavy reduction from 900C right up to the end
>which included a 30 minute soak still on heavy reduction.
> Now I just use a chun glaze in heavy reduction and spray copper
>carb.[powdered] into my burner ports, sparingly,just before optimum
>temperature [/\ 11] and finish up with my usual soak. I get beautiful red
>and blue flashing on a pale background.
> Regards
> Bob
>Hollis ----- Original Message -----
>From: Angela Young
>To:
>Sent: 24 July 1999 21:15
>Subject: copper red
>
>
>> '
>>
>> ----------------------------Original message----------------------------
>> Does anyone have recipe for Copper Red ^10 glaze?
>> It would be greatly appreciated.
>> thanks, angie from Tampa
>>
>
Iveragh Ceramics on thu 29 jul 99
Donald,
No, I also have a blue glaze and the copper turns this a
deep dark blue/purple/red but it seems to depend on the path of the flames
as some pots do not get any flashing so next firing I am going to leave a
larger gap between pots, could be a total disaster,but they can always be
refired. As my burners fire up through the base of the kiln this allowed me
to put a level teaspoon of cu.carb on each of the four burners and the
results were better, I put this on at cone 10 at 2.o,clock and I start my
1/2 hour soak when cone11 is almost flat.Very heavy reduction all the way
[black smoke job] .
Regards
Bob
-----Original Message-----
From: DONALD G. GOLDSOBEL
To: CLAYART@LSV.UKY.EDU
Date: Tuesday, July 27, 1999 10:49 PM
Subject: Re: copper red
----------------------------Original message----------------------------
Bob<
When you blow in the copper, is it into a kiln loaded with only clear chun
glazes? Could you be a bit more detailed. The idea is very appealing
Thank you Donald Goldsobel in the San Fernando Valley where we have unseasonalal cool
humid weather. A blessing after 90+ heat.
>----------------------------Original message----------------------------
>Dear Angela,
> Here are two glazes by Harriet Brisson.
>Feldspar 261-F 41.7
>Kaolin 1.7
>Flint 26.1
>Whiting 7.0
>Gerstley Borate 8.7
>Dolomite 8.7
>Zinc Oxide 6.1
>Tin Oxide 2.1
>Copper Carbonate 0.45
>
>Second Glaze:-
>Nepheline Syenite 42.4
>Feldspar 261-F 9.1
>Kaolin 2.0
>Flint 22.7
>Gerstley Borate 13.2
>Whiting 10.6
>Copper Carbonate 0.3
>Tin Oxide 1.0
>Both glazes worked for me with heavy reduction from 900C right up to the
end
>which included a 30 minute soak still on heavy reduction.
> Now I just use a chun glaze in heavy reduction and spray copper
>carb.[powdered] into my burner ports, sparingly,just before optimum
>temperature [/\ 11] and finish up with my usual soak. I get beautiful red
>and blue flashing on a pale background.
> Regards
> Bob
>Hollis ----- Original Message -----
>From: Angela Young
>To:
>Sent: 24 July 1999 21:15
>Subject: copper red
>
>
>> '
>>
>> ----------------------------Original message----------------------------
>> Does anyone have recipe for Copper Red ^10 glaze?
>> It would be greatly appreciated.
>> thanks, angie from Tampa
>>
>
Donald G. Goldsobel on sun 1 aug 99
At 04:48 PM 7/29/99 EDT, you wrote:
>----------------------------Original message----------------------------
>Donald,
> No, I also have a blue glaze and the copper turns this a
>deep dark blue/purple/red but it seems to depend on the path of the flames
>as some pots do not get any flashing so next firing I am going to leave a
>larger gap between pots, could be a total disaster,but they can always be
>refired. As my burners fire up through the base of the kiln this allowed me
>to put a level teaspoon of cu.carb on each of the four burners and the
>results were better, I put this on at cone 10 at 2.o,clock and I start my
>1/2 hour soak when cone11 is almost flat.Very heavy reduction all the way
>[black smoke job] .
>
>Regards
>
>Bob
>-----Original Message-----
>From: DONALD G. GOLDSOBEL
>To: CLAYART@LSV.UKY.EDU
>Date: Tuesday, July 27, 1999 10:49 PM
>Subject: Re: copper red
>
>
>----------------------------Original message----------------------------
>Bob<
>
>When you blow in the copper, is it into a kiln loaded with only clear chun
>glazes? Could you be a bit more detailed. The idea is very appealing
>
>Thank you >Donald Goldsobel in the San Fernando Valley where we have unseasonalal cool
>humid weather. A blessing after 90+ heat.
>
>>----------------------------Original message----------------------------
>>Dear Angela,
>> Here are two glazes by Harriet Brisson.
>>Feldspar 261-F 41.7
>>Kaolin 1.7
>>Flint 26.1
>>Whiting 7.0
>>Gerstley Borate 8.7
>>Dolomite 8.7
>>Zinc Oxide 6.1
>>Tin Oxide 2.1
>>Copper Carbonate 0.45
>>
>>Second Glaze:-
>>Nepheline Syenite 42.4
>>Feldspar 261-F 9.1
>>Kaolin 2.0
>>Flint 22.7
>>Gerstley Borate 13.2
>>Whiting 10.6
>>Copper Carbonate 0.3
>>Tin Oxide 1.0
>>Both glazes worked for me with heavy reduction from 900C right up to the
>end
>>which included a 30 minute soak still on heavy reduction.
>> Now I just use a chun glaze in heavy reduction and spray copper
>>carb.[powdered] into my burner ports, sparingly,just before optimum
>>temperature [/\ 11] and finish up with my usual soak. I get beautiful red
>>and blue flashing on a pale background.
>> Regards
>> Bob
>>Hollis ----- Original Message -----
>>From: Angela Young
>>To:
>>Sent: 24 July 1999 21:15
>>Subject: copper red
>>
>>
>>> '
>>>
>>> ----------------------------Original message----------------------------
>>> Does anyone have recipe for Copper Red ^10 glaze?
>>> It would be greatly appreciated.
>>> thanks, angie from Tampa
>>>
>>
>Ok Bob, one last question, if I may. How the hell do you get the cu co3 up
the burner port. My burners are 1\2 inch at most from the floor of the
kiln. I'll try anything half sane, but I can't quite figure a method to
introduce the powder via the burner port via the floor.
thanks
Donald
David Cuzick on mon 2 aug 99
Here are some copper reds that I have been using, they work best on porcelain
and the very best on grolleg porcelain such as Colemans porcelain sold at
Aardvark in LA or English porcelain sold at Laguna Clay (all over the place
in the west of USA)
Ox Blood Red cone 10 R
nepheline syenite 42.35
silica 22.7
colemanite 13.27
whiting 10.46
feldspar 9.18
EPK 2.04
add
tin oxide 1.7
copper oxide .26
this glaze needs good reduction to turn red, I mix it with the glaze which
follows, 2:3 ratio by volume, this gives the very best red.
Red, cone 10 R
silica 35.24
nepheline syenite 20.00
custer feldspar 15.24
whiting 15.40
colemanite 10.57
EPK 1.45
add
tin oxide 1.68
copper carbonate .42
a very nice purple red, needs early reduction, start reduction at ^010 and
light reduction there after.
You may also know that copper reds need to be applied med. thick, If they are
too thin the color will "burn" out. These glazes can run if they are too
thick, so be careful... in other words they need to be applied and fired just
so.. that's why they are so special
make good pots,
David Cuzick
San Diego,CA
Claycuzian@aol.com
Nick Zappa on sat 20 nov 99
-------------------
We fire our copper red to cone 10 then shut the kiln off and go to bed. We =
are
reducing at 1800 F. You can see our results at www.zappapottery.com we =
have
been doing it this way for over 25 years. Nick Zappa
Martin Howard on fri 26 jul 02
Just tested .5% CuO and .5% SiC in a white earthenware slip and then covered
with a clear glaze. Hoping for a copper red.
Just nothing, but white slip.
To get there should I increase or decrease the amounts of CuO and SiC?
What's your guess?
I fired first with the CuO and SiC in white earthenware slip. Nothing.
Then I put the clear glaze over and fired again. Nothing.
Should I slip and glaze at fire just once?
Any advice will be gratefully received:-)
Martin Howard
Webbs Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
01371 850 423
martin@webbscottage.co.uk
http://www.webbscottage.co.uk
Updated 6th July 2002
Marcia Selsor on sat 27 jul 02
Increase the copper. Sometimes I get a copper red by using a copper wash under
clear. It really bleeds but will work. Don't over do it or you'll get blisters. I
think you could go to 5% copper in the slip. But what else is in the slip?
Something there could be impeding the red.
Marcia in Montana
Martin Howard wrote:
> Just tested .5% CuO and .5% SiC in a white earthenware slip and then covered
> with a clear glaze. Hoping for a copper red.
> Just nothing, but white slip.
> To get there should I increase or decrease the amounts of CuO and SiC?
> What's your guess?
> I fired first with the CuO and SiC in white earthenware slip. Nothing.
> Then I put the clear glaze over and fired again. Nothing.
> Should I slip and glaze at fire just once?
> Any advice will be gratefully received:-)
>
> Martin Howard
> Webbs Cottage Pottery
> Woolpits Road, Great Saling
> BRAINTREE, Essex CM7 5DZ
> 01371 850 423
> martin@webbscottage.co.uk
> http://www.webbscottage.co.uk
> Updated 6th July 2002
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
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chris clarke on sun 28 jul 02
Hey Martin and everyone,
I get blood red with slip (cone ten). Has quite a bit of copper carb.
but I can't tell you exact numbers because I mix by color. I also add red
iron, but not tin. Try adding more then you think. Also, I just use my
clay as the base, b-mix.
By the way, you didn't say what cone you fire to?
chris
temecula, california
chris@ccpots.com
http://www.ccpots.com
Gene Arnold on sat 24 nov 07
Is there a cone 10 copper red recipe out there that is a fail safe =
always (or at least more success than failure) works everytime glaze. =
Each one that I have read about seems to be very finicky and =
unpredictable.=20
Gene=20
mudduck@mudduckpottery.net
www.mudduckpottery.net
Rod on sun 25 nov 07
Gene,
The only copper red'ish glaze that I know that is fool proof is a recipe I
tried years ago called "Pablo's Red". Not sure of the source of this glaze.
Not a true copper red (IMHO) but it is okay for some forms.
9701 Pablo's Red (c10r)
--------------------------
Custer feldspar 44.20
Flint 22.10
EPK kaolin 3.20
Whiting 8.40
Gerstley borate 11.60
Zinc oxide 4.20
Dolomite 6.30
--------
100.00
Tin oxide 3.00
Copper carbonate 1.50
IRON OXIDE RED 0.50
Na2O 0.08 Al2O3 0.25 SiO2 2.61
K2O 0.14 B2O3 0.14 P2O5 0.00
MgO 0.13 TiO2 0.00
CaO 0.47 Fe2O3 0.01
CuO 0.03 SnO2 0.06
ZnO 0.15
Alumina:Silica ratio is 1.00:10.42
Neutral:Acid ratio is 1.00:6.90
Alk:Neut:Acid ratio is 1.00:0.39:2.68
Expansion: 74.6 x 10e-7 per degree C
Oxides causing abnormal expansion:
B2O3
Note: I have found the zinc to be useless and think it is an "old school"
glaze addition in reduction firings. According to most sources it just
volatizes, and how much it takes part in the melt is of constant debate. I
can tell you from my experience that I've have never noticed a difference in
high fire reduction glazes if you leave out the zinc.
Other than that I can tell you as other copper red users will; Copper red
glazes are by nature finicky. The nicest copper reds have very low amounts
of copper in them, usually less than 1% added to the batch. Tin will help
stabilize the copper a bit, but this is not a silver bullet by any means.
If you start going over 1% the copper reds are livery in appearance and not
personally my favorite but some like it.
Copper reds are really all about the firing process, moderate reduction not
heavy; 5.5 - 6.0 on the oxy-probe. I personally have had better luck with
the entire kiln being copper red. That is of course a heart ache if you have
a bad firing.
I have heard of some pretty wacky firing schedules for copper reds - I've
never used them, start with a simple firing schedule and go from there. One
last thing - fire them "almost" as fast as you can, extended firings tend to
show your copper where the stack is and it finds its way up there without
further encouragement.
If you don't already own John Britt's EXCELLENT book I highly recommend it!
It is without question one of the best damn glaze firing books out there bar
none.
Good luck,
Rod
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Gene Arnold
Sent: Saturday, November 24, 2007 7:05 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: copper red
Is there a cone 10 copper red recipe out there that is a fail safe always
(or at least more success than failure) works everytime glaze. Each one that
I have read about seems to be very finicky and unpredictable.
Gene
mudduck@mudduckpottery.net
www.mudduckpottery.net
____________________________________________________________________________
__
Clayart members may send postings to: clayart@lsv.ceramics.org
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Bruce Girrell on mon 26 nov 07
Gene Arnold wrote:
>Is there a cone 10 copper red recipe out there that is a fail safe always
(or at least more success than failure) works everytime glaze.
>Each one that I have read about seems to be very finicky and unpredictable.
Ooooooohhhh, can I be the first to answer this one?
NO
and if I were using hypertext, I would put that in bold 30 pt font
See if you can find a copy of Copper Red Glazes by Robert Tichane. Not
necessarily a definitive treatise, but certainly a lot of useful
information.
Bruce Girrell
Tom at Hutchtel.net on mon 26 nov 07
OK Bruce got first dibbies.
Besides Tichane's book, look up John Britt's Cone 10 glazes.
Then start experimenting. Took Betsy maybe 6 to 9 months before she could
do the reds reliably. They are sensitive to thickness of application...if
you're not tracking density in he bucket, you're making it hard. then
they're sensitive to oxidation/reduction, and the time you enter reduction.
Then how you hold reduction during the firing. Then how you cool and how
leaky your kiln is. Do you strike on the way down or not.
So I go back, Gene to the experiment for yourself. If you scan the
archives, it's all there, and you'll quickly learn that it's different for
everybody....if I were Tony C I would have made an analogy there.
Oh Yeah...the firing schedule can screw up other glazes.
Happy reds to you!
Tom Wirt
----- Original Message -----
From: "Bruce Girrell"
To:
Sent: Monday, November 26, 2007 9:52 AM
Subject: Re: copper red
> Gene Arnold wrote:
>
>>Is there a cone 10 copper red recipe out there that is a fail safe always
> (or at least more success than failure) works everytime glaze.
>>Each one that I have read about seems to be very finicky and
>>unpredictable.
>
> Ooooooohhhh, can I be the first to answer this one?
>
> NO
>
> and if I were using hypertext, I would put that in bold 30 pt font
>
> See if you can find a copy of Copper Red Glazes by Robert Tichane. Not
> necessarily a definitive treatise, but certainly a lot of useful
> information.
>
> Bruce Girrell
>
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Bill Merrill on mon 31 jan 11
Copper reds are at their best in a high alkaline glaze base. I have
used the following glaze since the late 50's. The glaze is a Chun type
glaze that Carlton Ball formulated. It is a beautiful clear glaze at
cone 10 in reduction. It will fire higher than cone 10. This glaze is
listed in Carlton's' book " Making Pottery without a Wheel" . There are
lots of very good glazes in that book, from low fire to mid fire glazes.
His book also shows some very textural effects this glaze can produce
with the addition of other ingredients. The copper red is more rich on
Porcelain or a white body.
One of the reduction cone 10 glazes is listed as PM5, which is a glaze
Pete Meloy developed at the Bray foundation in the early 50's. He was a
lawyer for Archie Bray and made some nice pots also. The Meloy glaze is
a really nice eggshell mat glaze. I use it with a little black iron and
some Manganese. It is a beautiful tan glaze. Other colorants can be
used also...
=3D20
The Chun is also versatile, but we are talking copper red....The glaze
has lots of ingredients, but worth the effort of trying it. The book has
other colors Carlton used.
=3D20
Custer or G-200 spar 1440
=3D20
EPK 50
=3D20
Flint 900
=3D20
whiting 90
=3D20
Colemanite 300
=3D20
Dolomite 300
=3D20
Zinc 60
=3D20
Barium 150
=3D20
Tin 90
=3D20
17 grams of copper produces a copper red
=3D20
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