Joyce Lee, Jim Lee on sat 26 jul 97
Emily,
Are you talking about a ^6 lichen-type glaze? If so, I have many such
glaze recipes from Robin Hopper's Glaze and Colour Development class in
B.C. I'm sure others do, too. If this is what you want, do you want
different base glazes to which different percentages of colorants can be
added, or just a recipe for say a lichen with RIO?
Joyce
In the Mojave where we had to switch from the swamp cooler to the
air=conditioner (much more expensive) because of the overcast and RAIN!
Sandi Taylor on mon 6 dec 04
Dear Potters,
We are having difficulty getting orange peel in our salt kiln. Please =
advise me on what to do to get the pebbly orange peel. More sand,alumina =
or what? I do not know.
Perhaps there is a clay body suitable that can be used. Our classroom =
clay body looks nice and the slips are good but no orange peel and that =
is the look many of us want to get.
We can make the clay body as we compound our glazes and claybodies.
If all else fails we could buy the clay that will work but our instuctor =
frowns on bought clay bodies. He thinks we should make our own.
Thanks so much.
Sandi Taylor Manatee Community College in Bradenton,Fla.
Paul Herman on mon 6 dec 04
Hi Sandy,
First let me say your teacher is right, making clay can teach you a lot.
We should know our materials intimately.
When I started salt firing five years ago, it was from zero, and I had
to develop appropriate clay bodies. I make my own clays. My old brown
stoneware came out like chocolate syrup, and smooth white clays were
just that, smooth, white and uninteresting.
I soon noticed that one of the prettiest clays to come out of the salt
chamber was the wadding. (Hey Joe, look at these wads!) It is equal
parts sand, kaolin and Lincoln fireclay. Great leopard skin spotting and
orange peel. So I made some little pots out of wadding, and they were
great, black and clear leopard spots. But the clay is porous, you should
see my little shot glass bubble when doing the dishes.
So I started adding feldspar to make it vitreous, and ball clay to make
it plastic, and silica to improve glaze fit. I ended up (so far) with
this formula for "Wad Bod":
Lincoln #60 Fireclay
(or the same thing, IMCO 400 fireclay) 30
EPK kaolin 20
OM4 ball clay 20
70m silica sand 12
custer feldspar 10
200m silica 8
It makes good orange peel.
From my own observations, I think a moderate amount of Iron in the
claybody, and some sand or white grog will help you get orange peel.
Also "medium to heavy" salt.
good salty firings,
Paul Herman
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/
----------
>From: Sandi Taylor
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: orange peel
>Date: Mon, Dec 6, 2004, 5:38 AM
>
> Dear Potters,
> We are having difficulty getting orange peel in our salt kiln. Please
> advise me on what to do to get the pebbly orange peel. More sand,alumina or
> what? I do not know.
> Perhaps there is a clay body suitable that can be used. Our classroom clay
> body looks nice and the slips are good but no orange peel and that is the
> look many of us want to get.
> We can make the clay body as we compound our glazes and claybodies.
> If all else fails we could buy the clay that will work but our instuctor
> frowns on bought clay bodies. He thinks we should make our own.
> Thanks so much.
> Sandi Taylor Manatee Community College in Bradenton,Fla.
Marta Matray Gloviczki on tue 7 dec 04
Paul Herman wrote:
>I soon noticed that one of the prettiest clays to come out of the salt
>chamber was the wadding.>>>>>>>>>
hi paul,
i was wondering if your 'wad bod' would make a good slip?
or even a nice orange peel glaze...
than it could be used on top of your claybody...
if you`d come up with a recipe, please let us know,
i`d love to try it!
marta
====
marta matray gloviczki
rochester,mn
http://www.angelfire.com/mn2/marta/
http://users.skynet.be/russel.fouts/Marta.htm
http://www.silverhawk.com/crafts/gloviczki/welcome.html
__________________________________
Cynthia Bracker on tue 7 dec 04
Wedge in some Silica Sand or (preferably) Shot. That is what causes the
Orange Peel effect.
Cindy Bracker
Sandi Taylor wrote:
>Dear Potters,
>We are having difficulty getting orange peel in our salt kiln. Please advise me on what to do to get the pebbly orange peel. More sand,alumina or what? I do not know.
>Perhaps there is a clay body suitable that can be used. Our classroom clay body looks nice and the slips are good but no orange peel and that is the look many of us want to get.
>We can make the clay body as we compound our glazes and claybodies.
>If all else fails we could buy the clay that will work but our instuctor frowns on bought clay bodies. He thinks we should make our own.
>Thanks so much.
>Sandi Taylor Manatee Community College in Bradenton,Fla.
>
>______________________________________________________________________________
>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.
>
>
>
>
billBUCKNER on tue 7 dec 04
>Hello, Sandy:
>
>It has been my experience that most clay bodies will orange peel to some
>extent. Of course, there are some exceptions. I had a commercial white
>stoneware that I used for years in reduction - a beautiful body to use.
>But, in salt and soda, it developed a surface that was so consistent and
>flat (no orange peel texture) as to be rather boring. For that reason, I
>had to retire it.
>
>As you suggested and Paul concurred, you would do well to develop a body
>to your own specifications. Iron content is definitely a consideration if
>you are doing any significant reduction - which will produce "sewer pipe
>ware". Too much iron will also interfere with the formation of the glaze
>on the ware. Avoiding reduction usually produces anemic looking ware.
>
>On the other hand, porcelains are usually too white and produce rather
>sterile surfaces unless they are enhanced with glazes or flashing slips
>and the like.
>
>So, something in between is a good place to start. You can even blend a
>porcelain body and a stoneware body with some good results.
>
>I fire soda. But, these issues are pretty much the same for both salt and
>soda. I have some recipes (body, as well as glazes that work well in
>salt/soda) on my web site, . I would be interested to
>discuss it further if you like. You can post me directly from the web site.
>
>Cheers,
>-Bill Buckner
>Atlanta
billBUCKNER
www.sodaglaze.com
"Life's journey is not to arrive at the grave safely in a well preserved
body. But, rather to slide in sideways, totally worn out, shouting... Holy
$*^#. What a ride !!!" -Author unknown
Ivor and Olive Lewis on tue 7 dec 04
Dear Sandi Taylor,
I think your instructor is putting you between an extremely large rock
and a very hard place.
To answer your question is necessary to know the factual cause of an
orange peel surface. As far as I know this has never been determined
or described therefore any suggestions as to how you might achieve a
good reticulated surface would be speculative.
However, I have found that some Ball Clays, used as slips, will give
an orange orange peel surface. In addition, Mica D (Powdered Muscovite
available in Australia) added to a stoneware clay body promotes
reticulation in a cone 8 firing.
I would like to know how your instructor makes a clay body that will
perform in this way. Ask him what he uses.
Best regards,Ivor Lewis.
Redhill,
S. Australia.
----- Original Message -----
From: "Sandi Taylor"
To:
Sent: Tuesday, 7 December 2004 12:08
Subject: orange peel
Dear Potters,
We are having difficulty getting orange peel in our salt kiln. Please
advise me on what to do to get the pebbly orange peel. More
sand,alumina or what? I do not know.
Perhaps there is a clay body suitable that can be used. Our classroom
clay body looks nice and the slips are good but no orange peel and
that is the look many of us want to get.
We can make the clay body as we compound our glazes and claybodies.
If all else fails we could buy the clay that will work but our
instuctor frowns on bought clay bodies. He thinks we should make our
own.
Thanks so much.
Sandi Taylor Manatee Community College in Bradenton,Fla.
______________________________________________________________________
________
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.
Edwards on tue 7 dec 04
Hello Sandi: Free silica in a clay is a major factor in orange peel.
Silica in solution attracts, free silica repels. Cindy Bracker is right
on about wedging in silica sand. Hmmm... firing also has something to do
with it. Salting when the clay has vitrified helps to get a nice peel.
Make some draw rings-- when you think the clay is vitrified pull one out
and quench it in water, if there are radial cracks going all the way
from the center to the outside edge, your clay is hot enough. These draw
rings are also good to see how well of a coating your pots are getting.
Quick cooling will help develop a nice silvery luster to some salt bodies.
I first saw quick cooling in Hohr-Grenzhausen, in the mid 60's, at that
time there were several traditional wood-fired Westerwald style kilns
being fired, by the early 90's there were none. Very rapid cooling to
bisque temp. The trick is to have only one opening in the kiln, so there
is no draft.
I have put some rutile in the clay body, it didn't help with orange
peel, but got some really nice colors, more in the golden hues instead
of the trad silvery colors.
Good luck,
~Craig
Oh! here is a good tip-- drink the beer after you salt, not before!
________________
Craig Edwards, New London MN
e-mail craigedwards@charter.net
http://photobucket.com/albums/v11/credwards/
Sandi Taylor wrote:
>Dear Potters,
>We are having difficulty getting orange peel in our salt kiln. Please advise me on what to do to get the pebbly orange peel. More sand,alumina or what? I do not know.
>Perhaps there is a clay body suitable that can be used. Our classroom clay body looks nice and the slips are good but no orange peel and that is the look many of us want to get.
>We can make the clay body as we compound our glazes and claybodies.
>If all else fails we could buy the clay that will work but our instuctor frowns on bought clay bodies. He thinks we should make our own.
>Thanks so much.
>Sandi Taylor Manatee Community College in Bradenton,Fla.
>
>______________________________________________________________________________
>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.
>
>
>
Paul Herman on tue 7 dec 04
Hi Cindy,
You wrote:
<(preferably) Shot.>
What is "Shot"?
best,
Paul Herman
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/
----------
>From: Cynthia Bracker
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: orange peel
>Date: Tue, Dec 7, 2004, 12:23 PM
>
> Wedge in some Silica Sand or (preferably) Shot. That is what causes the
> Orange Peel effect.
> Cindy Bracker
Ivor and Olive Lewis on wed 8 dec 04
Perhaps we should remember that Historically "Orange Peel" was
regarded as a fault in some sections of the heavy clay industry.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Cynthia Bracker on wed 8 dec 04
"Flint Shot" or "Silica Shot" or just "Shot" is (more or less) the same
compositionally as silica sand, however, if you look at Shot under a
microscope, all the particles are the same size and shape, whereas sand
particles are irregular. They are often used interchangeably, however
shot will be a little less abrasive wedged into a body (However, if your
goal is also to add more tooth to the body, sand would be better than
shot). You can also use shot as "ball bearings" underneath a pot in a
firing. Because all the particles are rounded, it will work better than
sand for that purpose. Does that all make sense?
Cindy
Paul Herman wrote:
>Hi Cindy,
>
>You wrote:
>
><(preferably) Shot.>
>
>What is "Shot"?
>
>best,
>
>Paul Herman
>
>Great Basin Pottery
>Doyle, California US
>http://www.greatbasinpottery.com/
>
>----------
>
>
>>From: Cynthia Bracker
>>To: CLAYART@LSV.CERAMICS.ORG
>>Subject: Re: orange peel
>>Date: Tue, Dec 7, 2004, 12:23 PM
>>
>>
>>
>
>
>
>>Wedge in some Silica Sand or (preferably) Shot. That is what causes the
>>Orange Peel effect.
>>Cindy Bracker
>>
>>
>
>______________________________________________________________________________
>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.
>
>
>
>
Ivor and Olive Lewis on wed 8 dec 04
Dear Cynthia Bracker,
How do you explain this? Is it peculiar to silica or does it happen
with grog, or alumina sand
If it is a peculiarity of silica sand why did I get good orange peel
with a ball clay slip which has no coarse silica in its constitution?
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
> Wedge in some Silica Sand or (preferably) Shot. That is what causes
the
> Orange Peel effect.
> Cindy Bracker
Paul Herman on wed 8 dec 04
Hi Marta,
You asked:
I don't know if it would be a good slip, I haven't tried it. It would
work well, maybe.
I imagine it might be OK, but believe the sand/grog in the mix helps
promote orange peel. You could try it without sand or with, though with
might make it difficult to brush.
Note: On white clays, like 'B-mix' for example, the orange peel is
there, it just doesn't show up, and looks clear and glossy. A little
iron seems to bring it out.
Another Note: Some of the more interesting salt-slips here are high
alumina formulas. Either a slip containing mostly kaolin, or a standard
white slip mixed 50/50 with alumina. The alumina resists the dissolving
action of the salt. Interesting things seem to happen just as the slip
starts to give itself up to the melt. You've heard Mel rant about Gail
Nichols' pots, that's high alumina.
Good salty firings,
Paul Herman
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/
----------
>From: Marta Matray Gloviczki
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: orange peel
>Date: Tue, Dec 7, 2004, 4:58 AM
>
> hi paul,
>
> i was wondering if your 'wad bod' would make a good slip?
> or even a nice orange peel glaze...
> than it could be used on top of your claybody...
> if you`d come up with a recipe, please let us know,
> i`d love to try it!
>
> marta
Jim Murphy on thu 9 dec 04
Hello all,
Here's some pure speculation from yours truly.
A pebbly orange-peel surface [from Salt Glazing] suggests a possible cause
may be due to localized "differential surface tension" at the
claybody-saltvapor interface as evidenced by the many separate convex
menisci formed, i.e., the pebbly glaze [glass] texture.
Salt-glazers tell us they fire their ware usually to 2200-2400 F [high
enough for internal claybody volatile gases to have already been released
and a certain degree of vitrification to be attained], then add Salt into
the kiln allowing it to volatilize and eventually "something" pulls volatile
Na vapor into the claybody surface.
Assuming uniform kiln heat distribution prior to Salt addition, we may
expect claybody surface temperature to be uniform although quite possibly
with differential "surface vitrification" [glass formation]. So, what then
may account for differential pulling-forces [at the claybody surface]
creating a "differential surface tension" mechanism ?
I'll propose the "Orange-Peel" process is more a function of "surface pore
structure" surrounding surface Silicate particles [just prior to salt vapor
deposition].
Deeper small diameter surface pores [capillaries ?] would create more
suction than shallow large diameter pores, each creating suction force to
pull Na vapor in a differential manner.
In some claybodies - at the claybody surface - larger Silica particles,
certain Ball Clays [Illitic?], Mica, etc. may provide the impetus for
creating the necessary surrounding surface pore structure maximizing
orange-peel texture [due to their affect on localized claybody surface
"glass" formation].
Adding Silica Sand, etc. to just any old claybody though may or may not
create the "right" surface pore structure.
Perhaps this speculation may serve as potential thesis material for a
graduate Ceramics student.
Best wishes,
Jim Murphy
Cynthia Bracker on thu 9 dec 04
I can't say for certain, because I'm not familiar with Australian veins
of ball clay and what the composition is. Perhaps Ball Clay in
Australia is high in silica content. As Bonita Cohn mentioned in her
post, the silica bonds with the sodium in the salt creating beads of
glass (I really like that descriptive she used) which we refer to as
Orange Peel.
Cindy Bracker
Ivor and Olive Lewis wrote:
>Dear Cynthia Bracker,
>How do you explain this? Is it peculiar to silica or does it happen
>with grog, or alumina sand
>If it is a peculiarity of silica sand why did I get good orange peel
>with a ball clay slip which has no coarse silica in its constitution?
>Best regards,
>Ivor Lewis.
>Redhill,
>S. Australia.
>
>
>
>>Wedge in some Silica Sand or (preferably) Shot. That is what causes
>>
>>
>the
>
>
>>Orange Peel effect.
>>Cindy Bracker
>>
>>
>
>______________________________________________________________________________
>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.
>
>
>
>
Ivor and Olive Lewis on fri 10 dec 04
Dear Jim,
Wrote on nearby envelope this morning "High Surface Tension....Low
viscosity.... Poor wetting properties".
I have problems getting my head around your notion of gas or vapour
being able to exert a capillary force. But if you will accept the
following notions, for the sake of argument : (a) In spite of claims
that the sodium chloride becomes a dissociated gas the majority of
what comes into intimate contact with the clay is fluid. (b) Given
there is a vigorous chemical reaction between Sodium Chloride and both
Potash Felspar and Potash Mica (Muscovite) your idea of microporosity
being the site of things which cause the emergence of the soda rich
melt is, in my opinion, a most plausible way of thinking about
differential variations in the three qualities mentioned at the
beginning of my post.
By the way, I did some single substance tests back in 1987 and
reported my findings to the National Clay Conference at Sydney.
Specimens of silica that had been heated to cone 8 flat showed no sign
of reacting when given a heavy salting. Given the materials testing
models of Susan Peterson, Hutchinson-Cuff, Greg Daly as well as Cooper
and Royle I often wonder why those who insist that it is Silica that
is responsible for the formation of the glaze never test substances in
isolation. Must be in the "Too Hard Basket".
By the way, in support of (a) above, look at pages 26-7 in Jack Troy's
book, "Salt- Glazed Ceramics"
Best regards and have a wonderful festive season.
Ivor.
Ivor Lewis.
Redhill,
S. Australia.
----- Original Message -----
From: "Jim Murphy"
To:
Sent: Thursday, 9 December 2004 6:42
Subject: Re: orange peel
> Hello all,
>
> Here's some pure speculation from yours truly.
>
> A pebbly orange-peel surface [from Salt Glazing] suggests a possible
cause
> may be due to localized "differential surface tension" at the
> claybody-saltvapor interface as evidenced by the many separate
convex
> menisci formed, i.e., the pebbly glaze [glass] texture.
>
> Salt-glazers tell us they fire their ware usually to 2200-2400 F
[high
> enough for internal claybody volatile gases to have already been
released
> and a certain degree of vitrification to be attained], then add Salt
into
> the kiln allowing it to volatilize and eventually "something" pulls
volatile
> Na vapor into the claybody surface.
>
> Assuming uniform kiln heat distribution prior to Salt addition, we
may
> expect claybody surface temperature to be uniform although quite
possibly
> with differential "surface vitrification" [glass formation]. So,
what then
> may account for differential pulling-forces [at the claybody
surface]
> creating a "differential surface tension" mechanism ?
>
> I'll propose the "Orange-Peel" process is more a function of
"surface pore
> structure" surrounding surface Silicate particles [just prior to
salt vapor
> deposition].
>
> Deeper small diameter surface pores [capillaries ?] would create
more
> suction than shallow large diameter pores, each creating suction
force to
> pull Na vapor in a differential manner.
>
> In some claybodies - at the claybody surface - larger Silica
particles,
> certain Ball Clays [Illitic?], Mica, etc. may provide the impetus
for
> creating the necessary surrounding surface pore structure maximizing
> orange-peel texture [due to their affect on localized claybody
surface
> "glass" formation].
>
> Adding Silica Sand, etc. to just any old claybody though may or may
not
> create the "right" surface pore structure.
>
> Perhaps this speculation may serve as potential thesis material for
a
> graduate Ceramics student.
>
> Best wishes,
>
> Jim Murphy
>
>
______________________________________________________________________
________
> 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.
Ivor and Olive Lewis on fri 10 dec 04
Dear Cynthia,
Thank you for your reply.
Back in 1983 I became interested in salt glaze chemistry. One of the
facts which interested me was the reports from the Alkali Inspectorate
(UK) and the British Ceramic Research Association that kiln effluent
from industrial salt kilns contained almost as much Potassium Chloride
as Sodium Chloride as well; as other metallic chlorides. These results
are inconsistent with the popular way Salt glaze chemistry is
described for the studio potter and ceramic artist.
Among the tests I did was one which isolated each of the potential
ingredients of a clay body and tested them separately in Cone 8 Sodium
Chloride firings.
I tested Aluminium Hydrate, Silica, Kaolin, Ball clay, Potash felspar
and Muscovite Mica. The results were enlightening, showing quite
clearly that Silica alone would not form a glaze with Sodium Chloride,
that silica in chemical combination with Alumina was only marginally
affected.
In my reply to Jim Murphy I make the suggestion that people should do
single substance tests to gain deeper insights relating to their own
materials..
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Ivor and Olive Lewis on sat 11 dec 04
Jim,
By the way, did I tell you about the salt glazed piece that I have
that shows clearly salt of some description does enter into the
porosity of the clay.
Over a period of time this piece develops a pattern of efflorescent
crystals growing in the same patterns as the crazing of the glaze. The
crystals are not of the form one might expect from Sodium Chloride but
tend to be feathery instead of cubic or granular.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
There is so much knowledge to be discovered. When found, it often
contradicts conventional wisdom
Jim Murphy on sat 11 dec 04
on 12/9/04 7:13 PM, Ivor and Olive Lewis at iandol@WESTNET.COM.AU wrote:
> Wrote on nearby envelope this morning "High Surface Tension....Low
> viscosity.... Poor wetting properties".
> I have problems getting my head around your notion of gas or vapour
> being able to exert a capillary force.
Hi Ivor,
My Salt-Glaze "orange-peel" thinkin' process goes something like this:
a. Salt vapor begins wafting through the heated kiln.
b. The leading-edge of the very 1st vapor wavefront approaching the
[vitrified?] ware condenses - instantaneously - due to temperature
differential between the stationary heated ware surface and the moving vapor
[super-heated molecules?]. During firing, some claybodies may develop a
number of surface pores of such relative diameter and depth that a curved
meniscus (concave) of condensed molten liquid forms within these pore
openings.
c. The concave meniscii produce capillary suction force to the NEXT vapor
wavefront thereby pulling-in a "plug" of deposited molten liquid into each
of these pore openings. As more vapor wavefronts waft by, each molten "plug"
would oscillate slightly in & out [like the "air plug" at the soundhole of a
stringed acoustic instrument].
d. Saltvapor deposited "above" adjacent nonporous ware surface areas
undergoes no capillary suction and therefore no molten "plug" oscillation.
e. The wafting continues until finally all saltvapor is depleted or kiln
cooling freezes the viscous glass [and each pore "plug"] in place so the net
effect is a reticulated salt-glaze network of "convex" meniscii.
f. Tada ! - "Orange Peel!"
It would be interesting to view any available Tramsmission Electron
Micrograph (TEM) or etched SEM imagery of salt-glazed ware (flat tiles ?).
Perhaps we could then see where large residual Quartz (Silica) particles and
different-sized pore openings reside in relation to the "apex" and
low-valley perimeter of each convex meniscus and get "closer" to
understanding what's really going on.
FWIW, I have seen no such imagery myself.
Best wishes,
Jim Murphy
David Hewitt on sun 12 dec 04
This thread has been concerned with producing an orange peel effect with
salt glazing and I have found the possible explanations very
interesting.
I do not salt glaze myself, but do use vanadium trioxide or pentoxide as
a glaze ingredient. The majority, but not all the ones that I have
tried, do produce an orange peel surface. I would be most interested if
anyone has an explanation for this. I have none myself to offer as I
have just accepted that this happens and so use this experience to
advantage on selected items.
You can see examples of what I get from my web site under 'Pottery
Designs / Arcadia (Vanadium Glazes)'
David
--
David Hewitt
Web:- http://www.dhpot.demon.co.uk
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