John Christie on sun 17 feb 02
Date: Thu, 14 Feb 2002 07:58:04 -0500
From: Mitsuru Cope
Subject: Re: The Importance of Cured Wood/Flash
>John,
>Would you mind telling us what kind of wood ash is giving the most flashing
>in gas firing in your experience?
>Mitsuru Cope
>Montreal
>mitsuru@mitsurucope.com
>on 13/2/02 2:17 PM, John Christie at john@BLACKHILLSPOTTERY.CO.UK wrote:
>What is more
> surprising is the degree and quality of flashing on the inside of the
bowls
> associated with different wood ashes - which might give an indication of
> which wood to favour in a particular firing.
Dear Mitsuru,
I have not done enough work on this to be able to give you any definitive
answers though I shall continue to look. When I did my tests, I was hoping
to find out whether the matte areas that I was getting on some heavily ashed
pieces were the product of a particular wood ash rather than a fault which
could be traced back to the firing schedule. As Karen says, these can be a
virtue on a sculptural piece - but on a teabowl whose tactile quality is so
important (you go on holding the thing long after you have stopped looking
at it) they are unpleasant . I was surprised by the differences in flashing
produced by different wood ashes in the gas kiln and particularly by the
fact that washed ash produced no flashing at all. I have put a page at:
http://www.blackhillspottery.co.uk/flashing/
with photographs of some of the tests of different ashes and photographs of
the problem that I was hoping to throw some light on. As well as raking the
ashpits in the wood firing, I throw wood ash into the fireboxes (a gallon or
two in a 64 cu.ft chamber) towards the end of the firing (but before the
last couple of hours soak). If I want more flashing, I add more ash. So my
problem has to do with the quality of the flashing/fly ash (which as Merrie
Boerner says is are two different things) rather than the amount of it. The
ash additions to the fireboxes are accompanied by puffs of white vapour from
the chimney that last two or three seconds and any chimney flame is briefly
stained bright yellow (presumably by the volatile sodium salts in the ash).
Karen rightly points out the importance of the cooling cycle in the
development of the flashing. It is, as Karen says, in the cooling cycle
that the flashing really develops, not because of additional deposits, but
because of chemical changes (particularly in iron oxides). Too little
attention is given to this in the literature on glazes. Temmoku, Shino and
Nuka glazes are dramatically transformed by changes in the cooling cycle. I
have put an example of this on the page mentioned above.
John Christie
Morayshire, Scotland
Merrie Boerner on sun 17 feb 02
Hi John,
I call the obvious deposits of ash on the clay, and where the glaze
color has been changed because of ash deposit "fly ash" or "ash deposit".
I call the change in the color of the naked clay to orange, or to darker
brown "flashing".......it is just the language that somebody taught me.
We can have two different clay bodies, side by side, at the front of the
kiln.....getting the same amount of ash.....same wood......same
cooling....and one clay's ash deposit can be thick, mat, dull (I'm not sure,
but I think that clay has lots of iron).....and the other clay's ash deposit
can be runny, glassy, clear (that body has lots of Helmer).
That is all I seem to know about the subject...and am really interested in
this discussion !
Thanks,
Merrie
karen terpstra on mon 18 feb 02
John Christie wrote:
> ...I have put a page at:
> http://www.blackhillspottery.co.uk/flashing/
> with photographs of some of the tests of different ashes and photographs of
> the problem that I was hoping to throw some light on. As well as raking the
> ashpits in the wood firing, I throw wood ash into the fireboxes (a gallon or
> two in a 64 cu.ft chamber) towards the end of the firing (but before the
> last couple of hours soak). If I want more flashing, I add more ash...
>
I looked up your website of these tests. Bravo! I wish more of us
could do this. If I had more time and know how with web pages, I would
put up a picture of the black gunge, gunk, grunge that we had. I still
think it is different. My gunk was chunky on the bottom of the work.
The wadding was still intact. It had nothing do do with my recipe for
wadding.
I received an email the other day from a friend of mine who works for
one of the clay suppliers. He is testing zirconium and various
materials for kiln wash, brick coatings etc in his own wood kiln. He
said with testing in his anagama, he is finding that zirconium MAY get a
little tacky under certain conditions. While zirconium is more
refractory than alumina, it seems to get tacky at cone 5/6. Could I
have had the right conditions?! He will be at NCECA so I will show him
a doozy of a cup.
I like lots of color on my woodfired work. You seem to be getting nice
corals and deep color from flashing. I like a few of those grey/black
areas (see # 2. not what I call gunk) mixed in with the warm colors as
long as it's melted and just here and there.
Sometimes the matte texture that is going to occur in a wood kiln can be
fixed by washing/scrubbing the area with wet fine sand paper. You save
the piece, and have all that variety of color.
Of course this is just my personal opinion of what I like to see on my
work at the present time. Everyone's aesthetic is different when it
comes to wood firing. Wish I could hop on a plane, fly to the UK and
fire with you. Our method of closing down the kiln is different from
yours but it's very interesting and one method I might want to explore
sometime. I think shutting down a kiln can be very difficult and where
lots of mistakes can be made.
Happy Firings,
Karen Terpstra
La Crosse, WI
Richard Selfridge on tue 19 feb 02
Hi John,
I have, as you may have seen from the stuff on our web site, tried to use
combinations of shino type slips and limestone fluxed celadon glazes on
pots for use which need to be user friendly and not rough and ruckeled
where one's lip or hand touches them.
After looking at your images #1 and #4 it seems to me that what you are
getting is the fault of the basic incompatability of the neph sy shino
flashing slip and the high calcium fly ash. I no longer overlap the celadon
(fluxed with calcium carb.) glazes over the flashing slip, especially on
handles or rims as it always seems to try to shiver off or give the kind of
rough surface in your photos. The nose on the face in fig#1 and the edge of
the handle in fig#4 is exactly the kind of effect I get when I put the
limestone type glazes over the flashing slip. I also get this effect with
ash accumulations on the flashing slip especially if the pots have not
experienced a long time above cone 11.
The sequence of events goes something like this.
1) The flashing slip gets tacky and acts like fly paper early (cone 012) in
the firing especially on the edges or protrusions.
2) The flashing volatiles also have the same effects early in the firing.
The ash with its high calcium content sticks and accumulates in these areas.
3) The ash is fairly refractory because of the calcium and what is formed
is like a calcium matt glaze, immature because of the over supply of
calcium. Your practice of throwing the raw ash into the kiln near the end
of the firing would seem to magnify the effect especially if a long high
(above cone 10) temp. soak does not go with it. Owen Rye fires for over
four days and keeps the temp at or below cone 10 in order to build up
frosty semi matt surfaces. The following image on our site shows a bottle
of his in our collection which has this effect.
http://www.compusmart.ab.ca/selfridg/largepics/4sr28.jpg
4) Although this type of deposit is refractory below cone 11, once you
raise the temp above that the matt glaze deposit has a powerful fluxing
action and will really melt and move on vertical surfaces. The main effect
on the shino flashing slip is that the calcium bleaches out the orange and
often gives a pewter type finish.
If you look at the image on our site of a large plate you will see most of
the effects I have described. The plate was fired on edge and masked by a
plate in front of it. The left side of the plate is the hot pewter type
glaze which has eaten most of the flashing slip. A middle area before the
orange part shows the dryer accumulation of matt calcium ash and then the
orange of the flashing slip which has not been touched by much ash.
http://www.compusmart.ab.ca/selfridg/largepics/5sr45.jpg
Let me know if this makes any sense to you. I don't know anything about
Karen's black gunk and was only responding to the info that she was having
trouble getting wads apart. Your black markings seem to be a form of carbon
traping which we sometimes experience, often in the salt kiln. We got a
delightful teabowl from Christine Pedley in LaBorne this last April which
has a similar effect as a sort of halo around the edges of glaze drips
which I find quite attractive.
As you can see from the work on our web site we are pleased when we get
these kind of unique effects. Regards, Richard and Carol Selfridge
http://www.selfridgeceramicart.ca
Ruth Ballou on tue 19 feb 02
Ash effect lovers,
I've posted 3 scans of ash tests done on a biaxial grid at
http://albums.photo.epson.com/j/ViewPhoto?u=3006606&a=30112890&p=60427297&f=0 T
he lower right hand corner is a bit blown out, but I think the rest of the
tile comes through okay. These tests show the result of varying alumina and
silica on a grid of 35 glazes with a set group of flux materials. More
information on this method is available at < http://ian.currie.to/ >. I
use a 60/40 ratio of ash/spar for the flux corner (lower left corner). Clay
content increases to 50% as you move up the tile;silica increases to 60% as
you move to the right. I picked the 60/40 ratio based on a line blend of
ash/spar. Interestingly, this happens to be the same ratio of calcium/spar
for the .9 CaO grid from Ian's first book, Stoneware Glazes. Since a lot of
ash is predominately CaO, I don't think this is an accident that I that I
chose this ratio. I've learned that some of the Chinese lime historic
glazes have been analyzed to have .9 CaO (according to Nigel Wood's book).
I imagine that potters working with available materials have repeated these
experiments many times. For comparison, the single tiles are glaze 16 and
21 from the .9CaO set.
All these recent posts about ash on pots sent me to look at my grid tiles
again and compare them to a pot with a heavy hit of ash that was fired in a
train kiln.There on the pot are a range of the same glazes that appear in
the high clay area of both grids (ash/spar and .9 CaO) These glazes are low
in silica and have moderate amount of alumina. Makes sense as the
underlying clay body is contributing to the glaze.
Guess I'll go look at my tiles some more and see what else I see and think
about them some more.
Ruth Ballou
Silver Spring, MD
Didn't get to sit down much during the firing. Forgot my chair. Stood next
to the warm kiln instead. Unload tomorrow.
>Dear Mitsuru,
>I have not done enough work on this to be able to give you any definitive
>answers though I shall continue to look. When I did my tests, I was hoping
>to find out whether the matte areas that I was getting on some heavily ashed
>pieces were the product of a particular wood ash rather than a fault which
>could be traced back to the firing schedule. As Karen says, these can be a
>virtue on a sculptural piece - but on a teabowl whose tactile quality is so
>important (you go on holding the thing long after you have stopped looking
>at it) they are unpleasant . I was surprised by the differences in flashing
>produced by different wood ashes in the gas kiln and particularly by the
>fact that washed ash produced no flashing at all. I have put a page at:
>http://www.blackhillspottery.co.uk/flashing/
>with photographs of some of the tests of different ashes and photographs of
>the problem that I was hoping to throw some light on. As well as raking the
>ashpits in the wood firing, I throw wood ash into the fireboxes (a gallon or
>two in a 64 cu.ft chamber) towards the end of the firing (but before the
>last couple of hours soak). If I want more flashing, I add more ash. So my
>problem has to do with the quality of the flashing/fly ash (which as Merrie
>Boerner says is are two different things) rather than the amount of it. The
>ash additions to the fireboxes are accompanied by puffs of white vapour from
>the chimney that last two or three seconds and any chimney flame is briefly
>stained bright yellow (presumably by the volatile sodium salts in the ash).
>Karen rightly points out the importance of the cooling cycle in the
>development of the flashing. It is, as Karen says, in the cooling cycle
>that the flashing really develops, not because of additional deposits, but
>because of chemical changes (particularly in iron oxides). Too little
>attention is given to this in the literature on glazes. Temmoku, Shino and
>Nuka glazes are dramatically transformed by changes in the cooling cycle. I
>have put an example of this on the page mentioned above.
>John Christie
>Morayshire, Scotland
>
>______________________________________________________________________________
>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.
Tony Ferguson on tue 19 feb 02
Ruth,
Very cool and I wish we all did this. I think I will as soon as I figure
out the grid method. I have some combinations I want to try. What is the
composition of your clay body--how much feldspar (what kind) and iron?. I
may have some ideas for you if you want to change your body.
Thank you!
Tony Ferguson
Stoneware, Porcelain, Raku
www.aquariusartgallery.com
Photographic, Web Site, & Marketing Services for Artists
218-727-6339
315 N. Lake Ave
Apt 401
Duluth, MN 55806
----- Original Message -----
From: "Ruth Ballou"
To:
Sent: Tuesday, February 19, 2002 7:19 AM
Subject: Re: Flashing and cooling in wood-fired kilns
> Ash effect lovers,
>
> I've posted 3 scans of ash tests done on a biaxial grid at
>
http://albums.photo.epson.com/j/ViewPhoto?u=3006606&a=30112890&p=60427297&f=
0 T
> he lower right hand corner is a bit blown out, but I think the rest of the
> tile comes through okay. These tests show the result of varying alumina
and
> silica on a grid of 35 glazes with a set group of flux materials. More
> information on this method is available at < http://ian.currie.to/ >. I
> use a 60/40 ratio of ash/spar for the flux corner (lower left corner).
Clay
> content increases to 50% as you move up the tile;silica increases to 60%
as
> you move to the right. I picked the 60/40 ratio based on a line blend of
> ash/spar. Interestingly, this happens to be the same ratio of calcium/spar
> for the .9 CaO grid from Ian's first book, Stoneware Glazes. Since a lot
of
> ash is predominately CaO, I don't think this is an accident that I that I
> chose this ratio. I've learned that some of the Chinese lime historic
> glazes have been analyzed to have .9 CaO (according to Nigel Wood's book).
> I imagine that potters working with available materials have repeated
these
> experiments many times. For comparison, the single tiles are glaze 16 and
> 21 from the .9CaO set.
>
> All these recent posts about ash on pots sent me to look at my grid tiles
> again and compare them to a pot with a heavy hit of ash that was fired in
a
> train kiln.There on the pot are a range of the same glazes that appear in
> the high clay area of both grids (ash/spar and .9 CaO) These glazes are
low
> in silica and have moderate amount of alumina. Makes sense as the
> underlying clay body is contributing to the glaze.
>
> Guess I'll go look at my tiles some more and see what else I see and think
> about them some more.
>
> Ruth Ballou
> Silver Spring, MD
>
> Didn't get to sit down much during the firing. Forgot my chair. Stood next
> to the warm kiln instead. Unload tomorrow.
>
>
> >Dear Mitsuru,
> >I have not done enough work on this to be able to give you any definitive
> >answers though I shall continue to look. When I did my tests, I was
hoping
> >to find out whether the matte areas that I was getting on some heavily
ashed
> >pieces were the product of a particular wood ash rather than a fault
which
> >could be traced back to the firing schedule. As Karen says, these can be
a
> >virtue on a sculptural piece - but on a teabowl whose tactile quality is
so
> >important (you go on holding the thing long after you have stopped
looking
> >at it) they are unpleasant . I was surprised by the differences in
flashing
> >produced by different wood ashes in the gas kiln and particularly by the
> >fact that washed ash produced no flashing at all. I have put a page at:
> >http://www.blackhillspottery.co.uk/flashing/
> >with photographs of some of the tests of different ashes and photographs
of
> >the problem that I was hoping to throw some light on. As well as raking
the
> >ashpits in the wood firing, I throw wood ash into the fireboxes (a gallon
or
> >two in a 64 cu.ft chamber) towards the end of the firing (but before the
> >last couple of hours soak). If I want more flashing, I add more ash. So
my
> >problem has to do with the quality of the flashing/fly ash (which as
Merrie
> >Boerner says is are two different things) rather than the amount of it.
The
> >ash additions to the fireboxes are accompanied by puffs of white vapour
from
> >the chimney that last two or three seconds and any chimney flame is
briefly
> >stained bright yellow (presumably by the volatile sodium salts in the
ash).
> >Karen rightly points out the importance of the cooling cycle in the
> >development of the flashing. It is, as Karen says, in the cooling cycle
> >that the flashing really develops, not because of additional deposits,
but
> >because of chemical changes (particularly in iron oxides). Too little
> >attention is given to this in the literature on glazes. Temmoku, Shino
and
> >Nuka glazes are dramatically transformed by changes in the cooling cycle.
I
> >have put an example of this on the page mentioned above.
> >John Christie
> >Morayshire, Scotland
> >
>
>___________________________________________________________________________
___
> >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.
>
>
____________________________________________________________________________
__
> 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.
Hank Murrow on tue 19 feb 02
>Ruth,
>
>Very cool and I wish we all did this. I think I will as soon as I figure
>out the grid method. I have some combinations I want to try. What is the
>composition of your clay body--how much feldspar (what kind) and iron?. I
>may have some ideas for you if you want to change your body.
>
>Thank you!
>
>Tony Ferguson
Dear Tony;
Check with Ian Currie to see if he's coming to a venue near you
this spring. His workshop is an eye-opener! Know you'll enjoy it. Amazing!
After 44 years, I can still learn something new.
"Ian Currie"
Cheers, Hank in Eugene
Mitsuru Cope on tue 19 feb 02
Dear John,
Thank you for your information and the website. What a great way to show
the test results! Very clear!
This is not a wood firing... but in 1990, I did a series of test to obtain
orange colour and flashing in gas firing. I put wood ash and soda ash
solution in porcelain bowls and I got variety of red to oranges, grays,
blacks and whites. I even got luster like orange, too.
Now I am trying to re-create the same colours, but nothing comes close. I am
still using the same porcelain body and firing in the same gas kiln. I don't
know what kind of wood ashes I have used then but for sure I had never
washed them. I thought all ashes worked similar way because I got ashes from
several different friends' fire places and they all gave me an excellent
colours.
Last week, I dipped 4 pine cones in porcelain slip and fired at cone 9 gas
reduction. I got a beautiful orange colour inside of one of the pine cones.
The rests got no colours. I wonder what gave the orange colour in this case:
resin of the pine cone, enclosed atmosphere or pine ash?
The cooling was natural way. I'll try to fire down the next time.
I am going to take a wood/salt firing workshop in May, so I can do a lot of
interesting stuff that you've been doing. However, I am not sure if Tony
Clennell will let me throw wood ash into the fireboxes.
Regards,
Mitsuru Cope
Montreal
Canada
> I have not done enough work on this to be able to give you any definitive
> answers though I shall continue to look. When I did my tests, I was hoping
> to find out whether the matte areas that I was getting on some heavily ashed
> pieces were the product of a particular wood ash rather than a fault which
> could be traced back to the firing schedule. As Karen says, these can be a
> virtue on a sculptural piece - but on a teabowl whose tactile quality is so
> important (you go on holding the thing long after you have stopped looking
> at it) they are unpleasant . I was surprised by the differences in flashing
> produced by different wood ashes in the gas kiln and particularly by the
> fact that washed ash produced no flashing at all. I have put a page at:
> http://www.blackhillspottery.co.uk/flashing/
> with photographs of some of the tests of different ashes and photographs of
> the problem that I was hoping to throw some light on. As well as raking the
> ashpits in the wood firing, I throw wood ash into the fireboxes (a gallon or
> two in a 64 cu.ft chamber) towards the end of the firing (but before the
> last couple of hours soak). If I want more flashing, I add more ash. So my
> problem has to do with the quality of the flashing/fly ash (which as Merrie
> Boerner says is are two different things) rather than the amount of it. The
> ash additions to the fireboxes are accompanied by puffs of white vapour from
> the chimney that last two or three seconds and any chimney flame is briefly
> stained bright yellow (presumably by the volatile sodium salts in the ash).
> Karen rightly points out the importance of the cooling cycle in the
> development of the flashing. It is, as Karen says, in the cooling cycle
> that the flashing really develops, not because of additional deposits, but
> because of chemical changes (particularly in iron oxides). Too little
> attention is given to this in the literature on glazes. Temmoku, Shino and
> Nuka glazes are dramatically transformed by changes in the cooling cycle. I
> have put an example of this on the page mentioned above.
> John Christie
> Morayshire, Scotland
Ruth Ballou on wed 20 feb 02
I use a commercial clay from Highwater so I do not have the formula. It is
a low iron body. That test was fired in my gas kiln. I've done some testing
with Helmer and would like to do some more. I've added a pic of another
grid of the same clay, fired in the wood kiln. It is the same ash base with
5% TiO2 added.
http://albums.photo.epson.com/j/AlbumIndex?u=3006606&a=30112890&f=0
Ruth
>Ruth,
>
>Very cool and I wish we all did this. I think I will as soon as I figure
>out the grid method. I have some combinations I want to try. What is the
>composition of your clay body--how much feldspar (what kind) and iron?. I
>may have some ideas for you if you want to change your body.
>
>Thank you!
>
>Tony Ferguson
>Stoneware, Porcelain, Raku
>www.aquariusartgallery.com
>Photographic, Web Site, & Marketing Services for Artists
>218-727-6339
>315 N. Lake Ave
>Apt 401
>Duluth, MN 55806
>
>
>----- Original Message -----
>From: "Ruth Ballou"
>To:
>Sent: Tuesday, February 19, 2002 7:19 AM
>Subject: Re: Flashing and cooling in wood-fired kilns
>
>
>> Ash effect lovers,
>>
>> I've posted 3 scans of ash tests done on a biaxial grid at
>>
>http://albums.photo.epson.com/j/ViewPhoto?u=3006606&a=30112890&p=60427297&f=
>0 T
>> he lower right hand corner is a bit blown out, but I think the rest of the
>> tile comes through okay. These tests show the result of varying alumina
>and
>> silica on a grid of 35 glazes with a set group of flux materials. More
>> information on this method is available at < http://ian.currie.to/ >. I
>> use a 60/40 ratio of ash/spar for the flux corner (lower left corner).
>Clay
>> content increases to 50% as you move up the tile;silica increases to 60%
>as
>> you move to the right. I picked the 60/40 ratio based on a line blend of
>> ash/spar. Interestingly, this happens to be the same ratio of calcium/spar
>> for the .9 CaO grid from Ian's first book, Stoneware Glazes. Since a lot
>of
>> ash is predominately CaO, I don't think this is an accident that I that I
>> chose this ratio. I've learned that some of the Chinese lime historic
>> glazes have been analyzed to have .9 CaO (according to Nigel Wood's book).
>> I imagine that potters working with available materials have repeated
>these
>> experiments many times. For comparison, the single tiles are glaze 16 and
>> 21 from the .9CaO set.
>>
>> All these recent posts about ash on pots sent me to look at my grid tiles
>> again and compare them to a pot with a heavy hit of ash that was fired in
>a
>> train kiln.There on the pot are a range of the same glazes that appear in
>> the high clay area of both grids (ash/spar and .9 CaO) These glazes are
>low
>> in silica and have moderate amount of alumina. Makes sense as the
>> underlying clay body is contributing to the glaze.
>>
>> Guess I'll go look at my tiles some more and see what else I see and think
>> about them some more.
>>
>> Ruth Ballou
>> Silver Spring, MD
>>
>> Didn't get to sit down much during the firing. Forgot my chair. Stood next
>> to the warm kiln instead. Unload tomorrow.
>>
>>
>> >Dear Mitsuru,
>> >I have not done enough work on this to be able to give you any definitive
>> >answers though I shall continue to look. When I did my tests, I was
>hoping
>> >to find out whether the matte areas that I was getting on some heavily
>ashed
>> >pieces were the product of a particular wood ash rather than a fault
>which
>> >could be traced back to the firing schedule. As Karen says, these can be
>a
>> >virtue on a sculptural piece - but on a teabowl whose tactile quality is
>so
>> >important (you go on holding the thing long after you have stopped
>looking
>> >at it) they are unpleasant . I was surprised by the differences in
>flashing
>> >produced by different wood ashes in the gas kiln and particularly by the
>> >fact that washed ash produced no flashing at all. I have put a page at:
>> >http://www.blackhillspottery.co.uk/flashing/
>> >with photographs of some of the tests of different ashes and photographs
>of
>> >the problem that I was hoping to throw some light on. As well as raking
>the
>> >ashpits in the wood firing, I throw wood ash into the fireboxes (a gallon
>or
>> >two in a 64 cu.ft chamber) towards the end of the firing (but before the
>> >last couple of hours soak). If I want more flashing, I add more ash. So
>my
>> >problem has to do with the quality of the flashing/fly ash (which as
>Merrie
>> >Boerner says is are two different things) rather than the amount of it.
>The
>> >ash additions to the fireboxes are accompanied by puffs of white vapour
>from
>> >the chimney that last two or three seconds and any chimney flame is
>briefly
>> >stained bright yellow (presumably by the volatile sodium salts in the
>ash).
>> >Karen rightly points out the importance of the cooling cycle in the
>> >development of the flashing. It is, as Karen says, in the cooling cycle
>> >that the flashing really develops, not because of additional deposits,
>but
>> >because of chemical changes (particularly in iron oxides). Too little
>> >attention is given to this in the literature on glazes. Temmoku, Shino
>and
>> >Nuka glazes are dramatically transformed by changes in the cooling cycle.
>I
>> >have put an example of this on the page mentioned above.
>> >John Christie
>> >Morayshire, Scotland
>> >
>>
>>___________________________________________________________________________
>___
>> >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.
>>
>>
>____________________________________________________________________________
>__
>> 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.
>
>______________________________________________________________________________
>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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