liddybug2002 on sun 19 may 02
I am a second year Vis Arts student, with a rapidly approaching
assessment. I have been making spheres and would dearly love to
glaze them with a copper red. My problem is that I only have access
to an electric kiln. My glaze tests so foar have been less than
happy, with the only red appearing in blotches, with the rest of the
glaze looking a very unappealing grey. Could this be from carbon
trapping?? If anyone can give me some hints, I would be EXTREMELY
grateful! Or does anyone know of a glaze that would give a similar
kind of red? I am using Buff Raku with Trachyte, and am trying to
achieve an opaque red with a medium gloss.
Any help would be wonderful!
Liddy
Carol Tripp on tue 21 may 02
Hi Liddy,
You know that old saying about the grass being greener...? For pottery,
it's "the glazes out of the type of kiln I don't have are the ones I want."
Well, it seems you have two issues here; you want a copper red from an
electric kiln and you don't have much time. Take a step back and ask
yourself what are you trying to accomplish - the big picture so to speak.
Are you making forms and glazing them or are you on a glaze testing quest?
To get copper reds out of an electric kiln is a LONGGGG term project. Do
you have the time? Doesn't sound like it. Either you can try glazing your
globes with an iron red and then refiring them to bring out more "red" or
you can find another glaze that suits your forms and doesn't drive you
crazy. Remember your goal and try not to get extremely sidetracked.
Best of luck,
Carol
Liddy wrote:
>I am a second year Vis Arts student, with a rapidly approaching
>assessment. I have been making spheres and would dearly love to
>glaze them with a copper red. My problem is that I only have access
>to an electric kiln. My glaze tests so foar have been less than
>happy, with the only red appearing in blotches, with the rest of the
>glaze looking a very unappealing grey. Could this be from carbon
>trapping?? If anyone can give me some hints, I would be EXTREMELY
>grateful! Or does anyone know of a glaze that would give a similar
>kind of red? I am using Buff Raku with Trachyte, and am trying to
>achieve an opaque red with a medium gloss.
>Any help would be wonderful!
>
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Paul Taylor on tue 21 may 02
Dear liddy
Go get a copy of Ron and Johns book.
But here is the warning, since you are only learning; you may miss the
significance of some of the detail . I have not read the book but I expect
Ron has been very precise in his instructions; because for a copper red he
would have to be .
Firstly the materials have to be the same . Any substitution will put
the red, which is the most fussy of glaze, out of balance and it will not
work.
Also i suspect the particle size and the grades of all the materials have
to be right, especially the reducing agent to stoping the pot going green
and not red.
Also the firing will matter - the rate of heating and cooling . The
heating because you do not want to burn out all the reducing agent before
the firing finishes and the cooling for much the same reason, and also the
formation of the red depends on the cooling rate.
All these above are inter linked . Copper red glazes are a dynamic between
glaze and firing. There is obviously an optimum for all depending on the
nature of your fuel and materials. Even so it is a delicate balancing act.
It would be nice to think if you had other materials you could substitute
using the formula . That is worth a try, but if you do you may have to
change the firing slightly and Or the amount of reducing material - lots of
testing.
You can start to appreciate how much effort goes into a good copper red
which is why you see so many 'blotchy piebald and grays' being passed off as
copper reds.
I would be very wary of glazing your work in copper red unless you have
compleat control of the process. even then it is not a glaze to be using to
a deadline. If I were you I would go for a stained glaze that does not rely
on reduction . this will get rid of one of the variables. glazes containing
Rutile ( titanium) plus stains or oxides can give some nice glazes but again
there is a dynamic between recipe and firing ( heating, and temperature and
cooling ) with these glazes.
A clear glaze plus an opacifyer (like Zircon) and stain cuts the
variables down to just the recipe but you have by now realized that these
glazes are featurless and a bit mechanical looking.
You have inadvertently stumbled on the big secret: the more interesting
the glaze the more important the firing schedule . If you can grasp the
significance of this and have an opportunity to fire your own kilns you can
to use the firing to its optimum . Other wise you will have to just stick to
adjusting recipes and formulas to fit the firings at the college . But make
sure the kilns you use give the same schedule every firing or you will be
constantly let down.
If you want more info write to me and I will explain further.
--
Regards from Paul Taylor
http://www.anu.ie/westportpottery
The boy who announced that the king had no clothes was tortured for the
names of his confederates and then shot.
> From: liddybug2002
> Reply-To: Ceramic Arts Discussion List
> Date: Sun, 19 May 2002 07:07:39 -0000
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: copper red...HELP!!
>
> I am a second year Vis Arts student, with a rapidly approaching
> assessment. I have been making spheres and would dearly love to
> glaze them with a copper red. My problem is that I only have access
> to an electric kiln. My glaze tests so foar have been less than
> happy, with the only red appearing in blotches, with the rest of the
> glaze looking a very unappealing grey. Could this be from carbon
> trapping?? If anyone can give me some hints, I would be EXTREMELY
> grateful! Or does anyone know of a glaze that would give a similar
> kind of red? I am using Buff Raku with Trachyte, and am trying to
> achieve an opaque red with a medium gloss.
> Any help would be wonderful!
> Liddy
>
Ron Roy on tue 28 may 02
Hi Liddy
There is a little confusion here - The red (Raspberry) in our book is not a
copper red glaze - they only work in reduction firing. Our (John's) red
uses chrome and Tin to get red at cone 6.
Just to clarify - most of the glazes in our book were invented by John -
lots of hard work and understanding on his part - My contribution was
mostly in adjusting to get the reology and expansion right.
Just to confirm much of what Paul is saying about getting everything right
with copper reds - I think it has mostly to do with firing and cooling -
getting copper reds to work with other materials. It does require some
skill to replace materials it is true but not something we potters can do
with some concentrated thinking - and accurate analysis of the materials we
use.
RR
>Dear liddy
>
>Go get a copy of Ron and Johns book.
>
> But here is the warning, since you are only learning; you may miss the
>significance of some of the detail . I have not read the book but I expect
>Ron has been very precise in his instructions; because for a copper red he
>would have to be .
>> I am a second year Vis Arts student, with a rapidly approaching
>> assessment. I have been making spheres and would dearly love to
>> glaze them with a copper red. My problem is that I only have access
>> to an electric kiln. My glaze tests so foar have been less than
>> happy, with the only red appearing in blotches, with the rest of the
>> glaze looking a very unappealing grey. Could this be from carbon
>> trapping?? If anyone can give me some hints, I would be EXTREMELY
>> grateful! Or does anyone know of a glaze that would give a similar
>> kind of red? I am using Buff Raku with Trachyte, and am trying to
>> achieve an opaque red with a medium gloss.
>> Any help would be wonderful!
>> Liddy
Gregory Evans on wed 29 may 02
Nov. 1997 Ceramic Monthly has an article on cone 6 ox copper Red. You can
also purchase the frits for the glazes and the color mixtures from General
Color. http://www.generalcolor.com/ceramicglass.html.
Carol Tripp on thu 30 may 02
Gregory wrote:
>Nov. 1997 Ceramic Monthly has an article on cone 6 ox copper Red. You can
>also purchase the frits for the glazes and the color mixtures from General
>Color. http://www.generalcolor.com/ceramicglass.html.
>
Didn't someone once say there is a sucker born every minute? Well, hands up
all those who bought this Sampler Pack from General Color. I did and I can
say from long experience that if you want copper reds, save your money and
buy a gas kiln. Give Genl Color its due, they declare clearly that your
results may not look like those in CM and believe me, they won't. I wrote
earlier about this copper red quest and mentioned then that the "grass is
always greener..." Let's all try for the best out of the type of kiln we
have.
Best regards,
Carol
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