Dan Olson on sun 15 apr 12
Two days ago I put my new (used) kiln through its first glaze firing. It =
=3D
was
just awful. I'm in the process of narrowing down where everything went
wrong. I've got an idea of what happened but if you make it through the w=
=3D
all
of text and are able to give some speculation to where I went wrong I'll =
=3D
be
forever grateful.
First let me describe the hot mess that came out of the kiln (pun intende=
=3D
d).
I used a Temmoku, false ash, kaki, rutile blue, and oatmeal glaze.=3D20
1. False ash: came out okay at best, that one just needs some color adjus=
=3D
tment.=3D20
2. Temmoku: came out very thin, it is also a dark brown/purple color (nea=
=3D
rly
black) instead of the brown-to-black variation it should be, it is also a=
=3D
nd
odd satin matte instead of the high gloss that it should be. I have one
piece that came out a high gloss as it should be, but its a terrible poo
brown color.
3. Oatmeal: can barely tell there is any glaze where I applied it. It is =
=3D
a
stoney textured flat white and picks up any dirt/dust it comes in contact=
=3D
with. It should be a satin matte cream color (good liner glaze).
4. Rutile: This should be a rutile blue glaze, I don't even know what
happened with this one. Its the same texture as the oatmeal (stony, porou=
=3D
s,
matte) I know that TiO2 is a tan colorant so, i guess what I'm asking her=
=3D
e
is did I get the wrong rutile?
5. Kaki: Came out almost identical to the Temmoku. I think maybe one of t=
=3D
he
problems here is the spanish iron oxide I used, but I cant be sure since
I've used it before making glazes in college and it came out fine. It sho=
=3D
uld
be a dark, earthy brown with orange flecks throughout, high gloss.
All the glazes I have I've used before when I was in college so I know th=
=3D
at
they all work, I can count that out as a possible culprit. What I can't
count out is the fact that I fired to cone 7 instead of cone 9/10.
Now the actual firing process. This was an odd one and I think it was my
fault. I forgot to put the spy-plugs in for the first half of the firing =
=3D
or
so, which made the whole thing take much longer than it should have. I st=
=3D
ill
got the kiln to temp (between cone 6/7), but I'm wondering if the prolong=
=3D
ed
firing would have an effect on the glazes? Firing time was from 4:04pm
friday to 10am saturday morning. Another potential Huge mistake I may hav=
=3D
e
made is that I underfired the glazes compared to what I did in college. A=
=3D
ll
the glazes except the False ash are cone 10 but I asked around and was to=
=3D
ld
that they should still be okay for cone 6/7.
Sorry for creating so many variables to go over. Ideally I'd only make on=
=3D
e
mistake at a time but lets be serious, where's the fun in that? I'll neve=
=3D
r
stop learning if I can help it!
Dan
Dannon Rhudy on sun 15 apr 12
Dan, I can see a number of things that MIGHT have
been wrong, but mainly - why would you expect cone
9-10 glazes to mature at cone 7? Mostly, they don't.
Tenmoku might, depending on the recipe. Ash - well,
they are meant to run, and so they tend to have an
early melt anyway. Oatmeal glazes (depends on the
recipe) are going to need the extra heat to mature.
If they feel rough - not hot enough. Rutile Blue
is an iron blue - plus, fairly refractory - not
hot enough.
What kind of kiln?
You'll get lots of advice, but it seems to me that
your main problem was not thinking everything through
at the start. Slow down, make a plan, stick to the
plan. And don't expect glazes to mature two or three
cones early.
regards
Dannon Rhudy
-----Original Message-----
From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of Dan Olson
Sent: Sunday, April 15, 2012 10:16 AM
To: Clayart@LSV.CERAMICS.ORG
Subject: Glaze disaster.
Two days ago I put my new (used) kiln through its first glaze firing. It wa=
s
just awful. I'm in the process of narrowing down where everything went
wrong. I've got an idea of what happened but if you make it through the wal=
l
of text and are able to give some speculation to where I went wrong I'll be
forever grateful.
First let me describe the hot mess that came out of the kiln (pun intended)=
.
I used a Temmoku, false ash, kaki, rutile blue, and oatmeal glaze.
1. False ash: came out okay at best, that one just needs some color
adjustment.
2. Temmoku: came out very thin, it is also a dark brown/purple color (nearl=
y
black) instead of the brown-to-black variation it should be, it is also and
odd satin matte instead of the high gloss that it should be. I have one
piece that came out a high gloss as it should be, but its a terrible poo
brown color.
3. Oatmeal: can barely tell there is any glaze where I applied it. It is a
stoney textured flat white and picks up any dirt/dust it comes in contact
with. It should be a satin matte cream color (good liner glaze).
4. Rutile: This should be a rutile blue glaze, I don't even know what
happened with this one. Its the same texture as the oatmeal (stony, porous,
matte) I know that TiO2 is a tan colorant so, i guess what I'm asking here
is did I get the wrong rutile?
5. Kaki: Came out almost identical to the Temmoku. I think maybe one of the
problems here is the spanish iron oxide I used, but I cant be sure since
I've used it before making glazes in college and it came out fine. It shoul=
d
be a dark, earthy brown with orange flecks throughout, high gloss.
All the glazes I have I've used before when I was in college so I know that
they all work, I can count that out as a possible culprit. What I can't
count out is the fact that I fired to cone 7 instead of cone 9/10.
Now the actual firing process. This was an odd one and I think it was my
fault. I forgot to put the spy-plugs in for the first half of the firing or
so, which made the whole thing take much longer than it should have. I stil=
l
got the kiln to temp (between cone 6/7), but I'm wondering if the prolonged
firing would have an effect on the glazes? Firing time was from 4:04pm
friday to 10am saturday morning. Another potential Huge mistake I may have
made is that I underfired the glazes compared to what I did in college. All
the glazes except the False ash are cone 10 but I asked around and was told
that they should still be okay for cone 6/7.
Sorry for creating so many variables to go over. Ideally I'd only make one
mistake at a time but lets be serious, where's the fun in that? I'll never
stop learning if I can help it!
Dan
ronroy@CA.INTER.NET on sun 15 apr 12
Hi Dan,
It would be unusual for cone 10 glazes to do well at cone 6 or 7.
They would need to be adjusted to melt better at the lower temperature.
RR
Quoting Dan Olson :
> Two days ago I put my new (used) kiln through its first glaze firing. It =
was
> just awful. I'm in the process of narrowing down where everything went
> wrong. I've got an idea of what happened but if you make it through the w=
all
> of text and are able to give some speculation to where I went wrong I'll =
be
> forever grateful.
>
> First let me describe the hot mess that came out of the kiln (pun intende=
d).
> I used a Temmoku, false ash, kaki, rutile blue, and oatmeal glaze.
>
> 1. False ash: came out okay at best, that one just needs some color
> adjustment.
>
> 2. Temmoku: came out very thin, it is also a dark brown/purple color (nea=
rly
> black) instead of the brown-to-black variation it should be, it is also a=
nd
> odd satin matte instead of the high gloss that it should be. I have one
> piece that came out a high gloss as it should be, but its a terrible poo
> brown color.
>
> 3. Oatmeal: can barely tell there is any glaze where I applied it. It is =
a
> stoney textured flat white and picks up any dirt/dust it comes in contact
> with. It should be a satin matte cream color (good liner glaze).
>
> 4. Rutile: This should be a rutile blue glaze, I don't even know what
> happened with this one. Its the same texture as the oatmeal (stony, porou=
s,
> matte) I know that TiO2 is a tan colorant so, i guess what I'm asking her=
e
> is did I get the wrong rutile?
>
> 5. Kaki: Came out almost identical to the Temmoku. I think maybe one of t=
he
> problems here is the spanish iron oxide I used, but I cant be sure since
> I've used it before making glazes in college and it came out fine. It sho=
uld
> be a dark, earthy brown with orange flecks throughout, high gloss.
>
> All the glazes I have I've used before when I was in college so I know th=
at
> they all work, I can count that out as a possible culprit. What I can't
> count out is the fact that I fired to cone 7 instead of cone 9/10.
>
> Now the actual firing process. This was an odd one and I think it was my
> fault. I forgot to put the spy-plugs in for the first half of the firing =
or
> so, which made the whole thing take much longer than it should have. I st=
ill
> got the kiln to temp (between cone 6/7), but I'm wondering if the prolong=
ed
> firing would have an effect on the glazes? Firing time was from 4:04pm
> friday to 10am saturday morning. Another potential Huge mistake I may hav=
e
> made is that I underfired the glazes compared to what I did in college. A=
ll
> the glazes except the False ash are cone 10 but I asked around and was to=
ld
> that they should still be okay for cone 6/7.
>
> Sorry for creating so many variables to go over. Ideally I'd only make on=
e
> mistake at a time but lets be serious, where's the fun in that? I'll neve=
r
> stop learning if I can help it!
>
> Dan
>
James Freeman on sun 15 apr 12
On Sun, Apr 15, 2012 at 10:16 AM, Dan Olson wrote:
Two days ago I put my new (used) kiln through its first glaze firing. It wa=
s
just awful. I'm in the process of narrowing down where everything went
wrong.
Another potential Huge mistake I may have
made is that I underfired the glazes compared to what I did in college. All
the glazes except the False ash are cone 10 but I asked around and was told
that they should still be okay for cone 6/7.
Dan...
You've answered your own question. You simply under-fired all of your
work. Stick them all back in and fire to cone 10, and you will likely
salvage most of them.
It is a huge jump from cone 10 down to cone 6. 200 or so degrees may not
seem like much, but that, along with the shorter firing required to reach
the lower temperature, makes a huge difference. I have a couple of cone 10
glazes that I occasionally use at cone 6, but only because I like how they
look for sculptural purposes in their under-fired state. They are NOT
stable, food-safe, or anything else at this lower temperature, and often
cannot really be thought of as a glaze. They are really just a sintered or
minimally melted coating, likely entirely lacking the necessary clay/glaze
interface.
You can reformulate your glazes to fire properly at cone 6 (more flux, and
more active fluxes, which of course also more or less alters the nature of
the glaze), but it might be easier to just find or develop native cone 6
glazes with the look you are after.
Leaving the peeps out won't affect anything other than a slight increase in
your electric bill, with the possible exception of a small underfired spot
an a piece directly adjacent to the open hole.
Good luck!
...James
James Freeman
"Talk sense to a fool, and he calls you foolish."
-Euripides
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources
William & Susan Schran User on sun 15 apr 12
On 4/15/12 10:16 AM, "Dan Olson" wrote:
>All the glazes I have I've used before when I was in college so I know
>that
>they all work, I can count that out as a possible culprit. What I can't
>count out is the fact that I fired to cone 7 instead of cone 9/10.
This paragraph sums it up, just didn't fire high enough. I also suspect
the glazes might have been applied on the thin side. The length of the
firing (4pm - 10am) is not unusual for some folks but might be a bit long
for your kiln. Did you stay up all night with the firing? What type of
kiln, gas set up, all that stuff do you have?
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
Mike on mon 16 apr 12
Hi Dan,
Just from a quick read of your description, it sounds like you didn't
get hot enough. That's why so many came out stony matte.
On the upside, you can just refire them and they'll probably be ok.
Mike
in Taku, Japan
http://karatsupots.com
http://karatsupots.blogspot.com
Workshop in Taku 2012: The Simple Teabowl, May 12 - 18
http://karatsupots.com/workshop2012/2012home.html
http://workshopintaku2012.blogspot.com/
(2012/04/15 23:16), Dan Olson wrote:
> Two days ago I put my new (used) kiln through its first glaze firing. It =
was
> just awful. I'm in the process of narrowing down where everything went
> wrong. I've got an idea of what happened but if you make it through the w=
all
> of text and are able to give some speculation to where I went wrong I'll =
be
> forever grateful.
>
> First let me describe the hot mess that came out of the kiln (pun intende=
d).
> I used a Temmoku, false ash, kaki, rutile blue, and oatmeal glaze.
>
> 1. False ash: came out okay at best, that one just needs some color adjus=
tment.
>
> 2. Temmoku: came out very thin, it is also a dark brown/purple color (nea=
rly
> black) instead of the brown-to-black variation it should be, it is also a=
nd
> odd satin matte instead of the high gloss that it should be. I have one
> piece that came out a high gloss as it should be, but its a terrible poo
> brown color.
>
> 3. Oatmeal: can barely tell there is any glaze where I applied it. It is =
a
> stoney textured flat white and picks up any dirt/dust it comes in contact
> with. It should be a satin matte cream color (good liner glaze).
>
> 4. Rutile: This should be a rutile blue glaze, I don't even know what
> happened with this one. Its the same texture as the oatmeal (stony, porou=
s,
> matte) I know that TiO2 is a tan colorant so, i guess what I'm asking her=
e
> is did I get the wrong rutile?
>
> 5. Kaki: Came out almost identical to the Temmoku. I think maybe one of t=
he
> problems here is the spanish iron oxide I used, but I cant be sure since
> I've used it before making glazes in college and it came out fine. It sho=
uld
> be a dark, earthy brown with orange flecks throughout, high gloss.
>
> All the glazes I have I've used before when I was in college so I know th=
at
> they all work, I can count that out as a possible culprit. What I can't
> count out is the fact that I fired to cone 7 instead of cone 9/10.
>
> Now the actual firing process. This was an odd one and I think it was my
> fault. I forgot to put the spy-plugs in for the first half of the firing =
or
> so, which made the whole thing take much longer than it should have. I st=
ill
> got the kiln to temp (between cone 6/7), but I'm wondering if the prolong=
ed
> firing would have an effect on the glazes? Firing time was from 4:04pm
> friday to 10am saturday morning. Another potential Huge mistake I may hav=
e
> made is that I underfired the glazes compared to what I did in college. A=
ll
> the glazes except the False ash are cone 10 but I asked around and was to=
ld
> that they should still be okay for cone 6/7.
>
> Sorry for creating so many variables to go over. Ideally I'd only make on=
e
> mistake at a time but lets be serious, where's the fun in that? I'll neve=
r
> stop learning if I can help it!
>
> Dan
>
Jackie.Miller.Clay on mon 16 apr 12
Could it be that they are not just under fired, but also need to be in redu=
c=3D
tion. I don't know of an oxidation Temmoku for instance, but if anyone one =
d=3D
oes, I would love the recipe.
Jackie
On Apr 16, 2012, at 8:00 AM, Mike wrote:
> Hi Dan,
>=3D20
> Just from a quick read of your description, it sounds like you didn't
> get hot enough. That's why so many came out stony matte.
> On the upside, you can just refire them and they'll probably be ok.
>=3D20
> Mike
> in Taku, Japan
>=3D20
> http://karatsupots.com
> http://karatsupots.blogspot.com
>=3D20
> Workshop in Taku 2012: The Simple Teabowl, May 12 - 18
>=3D20
> http://karatsupots.com/workshop2012/2012home.html
>=3D20
> http://workshopintaku2012.blogspot.com/
>=3D20
>=3D20
> (2012/04/15 23:16), Dan Olson wrote:
>> Two days ago I put my new (used) kiln through its first glaze firing. It=
w=3D
as
>> just awful. I'm in the process of narrowing down where everything went
>> wrong. I've got an idea of what happened but if you make it through the =
w=3D
all
>> of text and are able to give some speculation to where I went wrong I'll=
b=3D
e
>> forever grateful.
>>=3D20
>> First let me describe the hot mess that came out of the kiln (pun intend=
e=3D
d).
>> I used a Temmoku, false ash, kaki, rutile blue, and oatmeal glaze.
>>=3D20
>> 1. False ash: came out okay at best, that one just needs some color adju=
s=3D
tment.
>>=3D20
>> 2. Temmoku: came out very thin, it is also a dark brown/purple color (ne=
a=3D
rly
>> black) instead of the brown-to-black variation it should be, it is also =
a=3D
nd
>> odd satin matte instead of the high gloss that it should be. I have one
>> piece that came out a high gloss as it should be, but its a terrible poo
>> brown color.
>>=3D20
>> 3. Oatmeal: can barely tell there is any glaze where I applied it. It is=
a=3D
>> stoney textured flat white and picks up any dirt/dust it comes in contac=
t=3D
>> with. It should be a satin matte cream color (good liner glaze).
>>=3D20
>> 4. Rutile: This should be a rutile blue glaze, I don't even know what
>> happened with this one. Its the same texture as the oatmeal (stony, poro=
u=3D
s,
>> matte) I know that TiO2 is a tan colorant so, i guess what I'm asking he=
r=3D
e
>> is did I get the wrong rutile?
>>=3D20
>> 5. Kaki: Came out almost identical to the Temmoku. I think maybe one of =
t=3D
he
>> problems here is the spanish iron oxide I used, but I cant be sure since
>> I've used it before making glazes in college and it came out fine. It sh=
o=3D
uld
>> be a dark, earthy brown with orange flecks throughout, high gloss.
>>=3D20
>> All the glazes I have I've used before when I was in college so I know t=
h=3D
at
>> they all work, I can count that out as a possible culprit. What I can't
>> count out is the fact that I fired to cone 7 instead of cone 9/10.
>>=3D20
>> Now the actual firing process. This was an odd one and I think it was my
>> fault. I forgot to put the spy-plugs in for the first half of the firing=
o=3D
r
>> so, which made the whole thing take much longer than it should have. I s=
t=3D
ill
>> got the kiln to temp (between cone 6/7), but I'm wondering if the prolon=
g=3D
ed
>> firing would have an effect on the glazes? Firing time was from 4:04pm
>> friday to 10am saturday morning. Another potential Huge mistake I may ha=
v=3D
e
>> made is that I underfired the glazes compared to what I did in college. =
A=3D
ll
>> the glazes except the False ash are cone 10 but I asked around and was t=
o=3D
ld
>> that they should still be okay for cone 6/7.
>>=3D20
>> Sorry for creating so many variables to go over. Ideally I'd only make o=
n=3D
e
>> mistake at a time but lets be serious, where's the fun in that? I'll nev=
e=3D
r
>> stop learning if I can help it!
>>=3D20
>> Dan
>>=3D20
Robert Harris on mon 16 apr 12
As far as I am aware, all Tenmokus are oxidation glazes. It does not
require a reduction atmosphere. BUT most Tenmokus do not work
particularly well in an electric kiln ... unless you fire down to
mimic the cooling of a fuel kiln ... as I do.
Robert
On Mon, Apr 16, 2012 at 12:14 PM, Jackie.Miller.Clay
wrote:
> Could it be that they are not just under fired, but also need to be in re=
=3D
duction. I don't know of an oxidation Temmoku for instance, but if anyone o=
=3D
ne does, I would love the recipe.
> Jackie
>
>
>
> On Apr 16, 2012, at 8:00 AM, Mike wrote:
>
>> Hi Dan,
>>
>> Just from a quick read of your description, it sounds like you didn't
>> get hot enough. That's why so many came out stony matte.
>> On the upside, you can just refire them and they'll probably be ok.
>>
>> Mike
>> in Taku, Japan
>>
>> http://karatsupots.com
>> http://karatsupots.blogspot.com
>>
>> Workshop in Taku 2012: The Simple Teabowl, =3DA0May 12 - 18
>>
>> http://karatsupots.com/workshop2012/2012home.html
>>
>> http://workshopintaku2012.blogspot.com/
>>
>>
>> (2012/04/15 23:16), Dan Olson wrote:
>>> Two days ago I put my new (used) kiln through its first glaze firing. I=
=3D
t was
>>> just awful. I'm in the process of narrowing down where everything went
>>> wrong. I've got an idea of what happened but if you make it through the=
=3D
wall
>>> of text and are able to give some speculation to where I went wrong I'l=
=3D
l be
>>> forever grateful.
>>>
>>> First let me describe the hot mess that came out of the kiln (pun inten=
=3D
ded).
>>> I used a Temmoku, false ash, kaki, rutile blue, and oatmeal glaze.
>>>
>>> 1. False ash: came out okay at best, that one just needs some color adj=
=3D
ustment.
>>>
>>> 2. Temmoku: came out very thin, it is also a dark brown/purple color (n=
=3D
early
>>> black) instead of the brown-to-black variation it should be, it is also=
=3D
and
>>> odd satin matte instead of the high gloss that it should be. I have one
>>> piece that came out a high gloss as it should be, but its a terrible po=
=3D
o
>>> brown color.
>>>
>>> 3. Oatmeal: can barely tell there is any glaze where I applied it. It i=
=3D
s a
>>> stoney textured flat white and picks up any dirt/dust it comes in conta=
=3D
ct
>>> with. It should be a satin matte cream color (good liner glaze).
>>>
>>> 4. Rutile: This should be a rutile blue glaze, I don't even know what
>>> happened with this one. Its the same texture as the oatmeal (stony, por=
=3D
ous,
>>> matte) I know that TiO2 is a tan colorant so, i guess what I'm asking h=
=3D
ere
>>> is did I get the wrong rutile?
>>>
>>> 5. Kaki: Came out almost identical to the Temmoku. I think maybe one of=
=3D
the
>>> problems here is the spanish iron oxide I used, but I cant be sure sinc=
=3D
e
>>> I've used it before making glazes in college and it came out fine. It s=
=3D
hould
>>> be a dark, earthy brown with orange flecks throughout, high gloss.
>>>
>>> All the glazes I have I've used before when I was in college so I know =
=3D
that
>>> they all work, I can count that out as a possible culprit. What I can't
>>> count out is the fact that I fired to cone 7 instead of cone 9/10.
>>>
>>> Now the actual firing process. This was an odd one and I think it was m=
=3D
y
>>> fault. I forgot to put the spy-plugs in for the first half of the firin=
=3D
g or
>>> so, which made the whole thing take much longer than it should have. I =
=3D
still
>>> got the kiln to temp (between cone 6/7), but I'm wondering if the prolo=
=3D
nged
>>> firing would have an effect on the glazes? Firing time was from 4:04pm
>>> friday to 10am saturday morning. Another potential Huge mistake I may h=
=3D
ave
>>> made is that I underfired the glazes compared to what I did in college.=
=3D
All
>>> the glazes except the False ash are cone 10 but I asked around and was =
=3D
told
>>> that they should still be okay for cone 6/7.
>>>
>>> Sorry for creating so many variables to go over. Ideally I'd only make =
=3D
one
>>> mistake at a time but lets be serious, where's the fun in that? I'll ne=
=3D
ver
>>> stop learning if I can help it!
>>>
>>> Dan
>>>
--=3D20
----------------------------------------------------------
| |
|
