Carol Tripp on sun 4 dec 05
I passed by the kiln area at Dubai Int'l Art Centre today and the stand-in
kiln guy stopped me. He'd used some kiln wash out of a bag (Potclays or
Potterycrafts) and the wash came off the shelves and stayed on the feet of
the pots. Uh-oh. Now all the students are upset with him. (He's just
standing in for the regular kiln woman and he's only following orders and is
actually the art centre carpenter.) Ok, that aside, I offered to come up
with a kiln wash recipe, thinking we had a big barrel of alumina hydrate.
No, it's a big barrel of alumina calcined and I know these two are different
in terms of LOI. I also know that the barrel of alumina calcined has been
around for some few years in the humid climate of Dubai. Could it all be
rehydrated and just like Alumina Hydrate in terms of measuring?
Ok, I know nothing about kiln wash. I don't use it and don't plan to at
home. (I'm an ITC100 and pancake sort of person). But I need to come up
with something to use at the art centre. An Archive search spits out a few
hundred combinations (reminds me of spagetti sauce recipes, must be millions
of them with the same main ingredients measured out differently). I want to
use what we have:
Alumina Calcined, Ball Clay (unknown variety, UK origin), China clay (aka
kaolin, from UK). I want the kiln guy to be able to paint it on the shelves
and fire. The kiln is electric, fires to ^9-10, the clay is stoneware.
What do you think of 80 Alumina Calcined and 20 Ball Clay? Or would 60
Alumina Calcined, 30 China Clay and 10 Bentonite be better? Or two parts
Alumina Calcined and one part China Clay?
I guess I am looking for a sure bet. The wash goes on, the pots don't stick
afterward (unless poorly glazed and no amount of kiln wash will fix that.)
Thanks very much.
Carol
Dubai, UAE
a/c off for the first time since April
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Deborah Grant on sun 4 dec 05
Why don't you just try the old tried and true 50% silica (flint) and 50%
china clay or kaolin?
Debby Grant in New Hampshire
>From: Carol Tripp
>Reply-To: Clayart
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Alumina calcined use in kiln wash ?
>Date: Sun, 4 Dec 2005 08:40:56 +0000
>
>I passed by the kiln area at Dubai Int'l Art Centre today and the stand-in
>kiln guy stopped me. He'd used some kiln wash out of a bag (Potclays or
>Potterycrafts) and the wash came off the shelves and stayed on the feet of
>the pots. Uh-oh. Now all the students are upset with him. (He's just
>standing in for the regular kiln woman and he's only following orders and
>is
>actually the art centre carpenter.) Ok, that aside, I offered to come up
>with a kiln wash recipe, thinking we had a big barrel of alumina hydrate.
>No, it's a big barrel of alumina calcined and I know these two are
>different
>in terms of LOI. I also know that the barrel of alumina calcined has been
>around for some few years in the humid climate of Dubai. Could it all be
>rehydrated and just like Alumina Hydrate in terms of measuring?
>
>Ok, I know nothing about kiln wash. I don't use it and don't plan to at
>home. (I'm an ITC100 and pancake sort of person). But I need to come up
>with something to use at the art centre. An Archive search spits out a few
>hundred combinations (reminds me of spagetti sauce recipes, must be
>millions
>of them with the same main ingredients measured out differently). I want
>to
>use what we have:
>Alumina Calcined, Ball Clay (unknown variety, UK origin), China clay (aka
>kaolin, from UK). I want the kiln guy to be able to paint it on the
>shelves
>and fire. The kiln is electric, fires to ^9-10, the clay is stoneware.
>
>What do you think of 80 Alumina Calcined and 20 Ball Clay? Or would 60
>Alumina Calcined, 30 China Clay and 10 Bentonite be better? Or two parts
>Alumina Calcined and one part China Clay?
>
>I guess I am looking for a sure bet. The wash goes on, the pots don't
>stick
>afterward (unless poorly glazed and no amount of kiln wash will fix that.)
>
>Thanks very much.
>
>Carol
>Dubai, UAE
>a/c off for the first time since April
>
>_________________________________________________________________
>Express yourself instantly with MSN Messenger! Download today it's FREE!
>http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
>
>______________________________________________________________________________
>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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Earl Brunner on sun 4 dec 05
She said the standard kilnwash "stuck". Alumina hydrate makes a far superior kiln wash
Alumina hydrate 60
EPK 30
Bentonite 10
Deborah Grant wrote:
Why don't you just try the old tried and true 50% silica (flint) and 50%
china clay or kaolin?
Debby Grant in New Hampshire
>From: Carol Tripp
>Reply-To: Clayart
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Alumina calcined use in kiln wash ?
>Date: Sun, 4 Dec 2005 08:40:56 +0000
>
>I passed by the kiln area at Dubai Int'l Art Centre today and the stand-in
>kiln guy stopped me. He'd used some kiln wash out of a bag (Potclays or
>Potterycrafts) and the wash came off the shelves and stayed on the feet of
>the pots. Uh-oh. Now all the students are upset with him. (He's just
>standing in for the regular kiln woman and he's only following orders and
>is
>actually the art centre carpenter.) Ok, that aside, I offered to come up
>with a kiln wash recipe, thinking we had a big barrel of alumina hydrate.
>No, it's a big barrel of alumina calcined and I know these two are
>different
>in terms of LOI. I also know that the barrel of alumina calcined has been
>around for some few years in the humid climate of Dubai. Could it all be
>rehydrated and just like Alumina Hydrate in terms of measuring?
>
>Ok, I know nothing about kiln wash. I don't use it and don't plan to at
>home. (I'm an ITC100 and pancake sort of person). But I need to come up
>with something to use at the art centre. An Archive search spits out a few
>hundred combinations (reminds me of spagetti sauce recipes, must be
>millions
>of them with the same main ingredients measured out differently). I want
>to
>use what we have:
>Alumina Calcined, Ball Clay (unknown variety, UK origin), China clay (aka
>kaolin, from UK). I want the kiln guy to be able to paint it on the
>shelves
>and fire. The kiln is electric, fires to ^9-10, the clay is stoneware.
>
>What do you think of 80 Alumina Calcined and 20 Ball Clay? Or would 60
>Alumina Calcined, 30 China Clay and 10 Bentonite be better? Or two parts
>Alumina Calcined and one part China Clay?
>
>I guess I am looking for a sure bet. The wash goes on, the pots don't
>stick
>afterward (unless poorly glazed and no amount of kiln wash will fix that.)
>
>Thanks very much.
>
>Carol
>Dubai, UAE
>a/c off for the first time since April
Earl Brunner
e-mail: brunv53@yahoo.com
skiasonaranthropos@FSMAIL.NET on mon 5 dec 05
Hi Malcolm,
Whilst Id agree that its better to use kaolin rather than ball clay in
kiln wash are you sure that its presence leads to the formation of a
eutectic?
Regards
Antony
Malcolm Cooke on mon 5 dec 05
Do not use Ball clay in kiln Wash it will lower the eutectics and
make it fuse use only Kaolin at least 25-30% of the mix is enough
with the alumina this makes a very smooth wash for shelves and lasts
a long time we also use this in the wood kiln as well.
On 05/12/2005, at 9:14 AM, Deborah Grant wrote:
> Why don't you just try the old tried and true 50% silica (flint)
> and 50%
> china clay or kaolin?
>
> Debby Grant in New Hampshire
>
>
>> From: Carol Tripp
>> Reply-To: Clayart
>> To: CLAYART@LSV.CERAMICS.ORG
>> Subject: Alumina calcined use in kiln wash ?
>> Date: Sun, 4 Dec 2005 08:40:56 +0000
>>
>> I passed by the kiln area at Dubai Int'l Art Centre today and the
>> stand-in
>> kiln guy stopped me. He'd used some kiln wash out of a bag
>> (Potclays or
>> Potterycrafts) and the wash came off the shelves and stayed on the
>> feet of
>> the pots. Uh-oh. Now all the students are upset with him. (He's
>> just
>> standing in for the regular kiln woman and he's only following
>> orders and
>> is
>> actually the art centre carpenter.) Ok, that aside, I offered to
>> come up
>> with a kiln wash recipe, thinking we had a big barrel of alumina
>> hydrate.
>> No, it's a big barrel of alumina calcined and I know these two are
>> different
>> in terms of LOI. I also know that the barrel of alumina calcined
>> has been
>> around for some few years in the humid climate of Dubai. Could it
>> all be
>> rehydrated and just like Alumina Hydrate in terms of measuring?
>>
>> Ok, I know nothing about kiln wash. I don't use it and don't plan
>> to at
>> home. (I'm an ITC100 and pancake sort of person). But I need to
>> come up
>> with something to use at the art centre. An Archive search spits
>> out a few
>> hundred combinations (reminds me of spagetti sauce recipes, must be
>> millions
>> of them with the same main ingredients measured out differently).
>> I want
>> to
>> use what we have:
>> Alumina Calcined, Ball Clay (unknown variety, UK origin), China
>> clay (aka
>> kaolin, from UK). I want the kiln guy to be able to paint it on the
>> shelves
>> and fire. The kiln is electric, fires to ^9-10, the clay is
>> stoneware.
>>
>> What do you think of 80 Alumina Calcined and 20 Ball Clay? Or
>> would 60
>> Alumina Calcined, 30 China Clay and 10 Bentonite be better? Or
>> two parts
>> Alumina Calcined and one part China Clay?
>>
>> I guess I am looking for a sure bet. The wash goes on, the pots
>> don't
>> stick
>> afterward (unless poorly glazed and no amount of kiln wash will
>> fix that.)
>>
>> Thanks very much.
>>
>> Carol
>> Dubai, UAE
>> a/c off for the first time since April
>>
>> _________________________________________________________________
>> Express yourself instantly with MSN Messenger! Download today it's
>> FREE!
>> http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
>>
>> _____________________________________________________________________
>> _________
>> 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.
>
> _________________________________________________________________
> On the road to retirement? Check out MSN Life Events for advice on
> how to
> get there! http://lifeevents.msn.com/category.aspx?cid=Retirement
>
> ______________________________________________________________________
> ________
> 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.
Malcolm Cooke
Identity Environment & Art and
The Art Shed
7 Naas Rd
Tharwa ACT 2620
02 62355644
Earl Brunner on tue 6 dec 05
Ask Tom Coleman.
John Jensen wrote: Earl;
What does the Bentonite do to improve the kiln wash? I use half and half
alumina and Kaolin, which seems to work pretty well; but I'm open to
suggestions.
John Jensen, Mudbug Pottery
John Jensen@mudbugpottery.com
http://www.toadhouse.com http://www.mudbugpottery.com
http://www.mudbugblues.com
>
> She said the standard kilnwash "stuck". Alumina hydrate makes a far
> superior kiln wash
>
> Alumina hydrate 60
> EPK 30
> Bentonite 10
>
> Earl Brunner
> e-mail: brunv53@yahoo.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.
Earl Brunner
e-mail: brunv53@yahoo.com
Ivor and Olive Lewis on tue 6 dec 05
Dear Deborah Grant,
I would not use this mixture because it is a health hazard.
Substituting either Calcined Alumina or Aluminium Hydrate removes much =
of the danger from Silicosis from your recipe <>
=20
<<50%
china clay or kaolin?>>>
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Steve Mills on tue 6 dec 05
Dear Carol,
The kiln wash recipe that I use is very simple and stays on the
shelves. It consists of two parts by weight of Alumina Hydrate, and one
part China Clay (Kaolin). Applied thickness is up to you, I use it
fairly lightly except in my salt kiln, and it needs to be stirred
constantly as it settles at the speed of light.
As you only have calcined Alumina, I suggest you dust the surface of the
shelves with that alone as a dry powder. For this technique I use a 60
mesh sieve with a small coin in it to help the Alumina through, and wipe
the edges of the shelves with a cloth to prevent overspill. After a
firing the Alumina can be tipped onto a piece of paper and recycled for
the same purpose.
All the best
Steve Mills
In message , Carol Tripp writes
>I passed by the kiln area at Dubai Int'l Art Centre today and the stand-i=
>n
>kiln guy stopped me. He'd used some kiln wash out of a bag (Potclays or
>Potterycrafts) and the wash came off the shelves and stayed on the feet o=
>f
>the pots. Uh-oh. Now all the students are upset with him. (He's just
>standing in for the regular kiln woman and he's only following orders and=
> is
>actually the art centre carpenter.) Ok, that aside, I offered to come up
>with a kiln wash recipe, thinking we had a big barrel of alumina hydrate.
>No, it's a big barrel of alumina calcined and I know these two are differ=
>ent
>in terms of LOI. I also know that the barrel of alumina calcined has bee=
>n
>around for some few years in the humid climate of Dubai. Could it all be
>rehydrated and just like Alumina Hydrate in terms of measuring?
>
>Ok, I know nothing about kiln wash. I don't use it and don't plan to at
>home. (I'm an ITC100 and pancake sort of person). But I need to come up
>with something to use at the art centre. An Archive search spits out a f=
>ew
>hundred combinations (reminds me of spagetti sauce recipes, must be milli=
>ons
>of them with the same main ingredients measured out differently). I want=
> to
>use what we have:
>Alumina Calcined, Ball Clay (unknown variety, UK origin), China clay (aka
>kaolin, from UK). I want the kiln guy to be able to paint it on the shel=
>ves
>and fire. The kiln is electric, fires to ^9-10, the clay is stoneware.
>
>What do you think of 80 Alumina Calcined and 20 Ball Clay? Or would 60
>Alumina Calcined, 30 China Clay and 10 Bentonite be better? Or two parts
>Alumina Calcined and one part China Clay?
>
>I guess I am looking for a sure bet. The wash goes on, the pots don't st=
>ick
>afterward (unless poorly glazed and no amount of kiln wash will fix that.=
>)
>
>Thanks very much.
>
>Carol
>Dubai, UAE
>a/c off for the first time since April
>
>_________________________________________________________________
>Express yourself instantly with MSN Messenger! Download today it's FREE!
>http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
--
Steve Mills
Bath
UK
William & Susan Schran User on tue 6 dec 05
On 12/5/05 9:31 PM, "Ivor and Olive Lewis" wrote:
> Substituting either Calcined Alumina or Aluminium Hydrate removes much of the
> danger from Silicosis from your recipe <>
>
> <<> china clay or kaolin?>>>
I agree totally with Ivan on this.
Our kiln wash is : 1/2 alumina hydrate, 1/2 EPK - by VOLUME! An equal scoop
of both. Works well, doesn't flake, no plucking at ^10.
FYI - We got ten, 12x24 Advancer shelves a couple months ago for our gas
kiln, ^10 firings. We use no kiln wash. Get some major glaze drips from
students. Couple light taps with a chisel and a quick going over with angle
grinder fitted with masonry grinding wheel clean it right up.
I'm sold - will be purchasing 10 more soon!
FYI - Previously contacted Baileys & Axner to purchase Advancer shelves. Was
told would be shipped in 8-10 weeks! Contacted www.kilnshelf.com, got the
shelves in one week! Apparently they supply the shelves to the other
distributors.
-- William "Bill" Schran
Fredericksburg, Virginia
wschran@cox.net
wschran@nvcc.edu
John Jensen on tue 6 dec 05
Earl;
What does the Bentonite do to improve the kiln wash? I use half and half
alumina and Kaolin, which seems to work pretty well; but I'm open to
suggestions.
John Jensen, Mudbug Pottery
John Jensen@mudbugpottery.com
http://www.toadhouse.com http://www.mudbugpottery.com
http://www.mudbugblues.com
>
> She said the standard kilnwash "stuck". Alumina hydrate makes a far
> superior kiln wash
>
> Alumina hydrate 60
> EPK 30
> Bentonite 10
>
> Earl Brunner
> e-mail: brunv53@yahoo.com
skiasonaranthropos@FSMAIL.NET on wed 7 dec 05
A low percentage of bentonite in kiln wash will be a suspension agent,
which is very important for when a material as dense as alumina is mixed
with water
Regards,
Antony
John Britt on wed 7 dec 05
John,
You really don't need any bentonite. You can use Alumina Hydrate 50/EPK 50
or 60/ 40. You can weigh it or just do one scoop of each. It is very
forgiving. It is only kiln wash.
The recipe below has 30% clay in it (EPK) and that should be sufficient to
suspend that alumina. Bentonite swells about 50% and can cause cracking.
I just try to keep it simple.
Incidently, I have a chart of kiln wash recipes (pg. 169)in my book which
show the range of ingredients to help give you an understanding of how/why
various combinations work.
Hope it helps,
John Britt
www.johnbrittpottery.com
>What does the Bentonite do to improve the kiln wash? I use half and half
>alumina and Kaolin, which seems to work pretty well; but I'm open to
>suggestions.
>
>> Alumina hydrate 60
>> EPK 30
>> Bentonite 10
>>
Craig Martell on wed 7 dec 05
John Britt was saying
>You can use Alumina Hydrate 50/EPK 50 or 60/ 40.
Hello Shelf Washers:
Why do folks use alumina hydrate? I see no advantage over alumina oxide
other than price.
Alumina Hydrate has a loss on ignition of about 35% which means you are
only getting 65% alumina in the wash. I use a wash of 75% alumina oxide
(this is calcined and has no LOI) 25% china clay. It works very well and I
don't need to rewash very much. Every 6th or 7th firing I do some touch ups.
I used to be able to get some 100 mesh alumina oxide that's made in Japan
but haven't seen it around for awhile. The larger mesh was nice in terms
of allowing pots to move easily when undergoing firing shrinkage.
just wondering about the hydrate, Craig Martell Hopewell, Oregon
Ivor and Olive Lewis on wed 7 dec 05
Now I understand Malcolm.
You are using "Eutectic" in its simplistic sense, meaning "To melt =
easily" and not in its Scientific Sense, as defined in "Phase Diagrams =
for Ceramists" .
Funny you should choose Barium Carbonate as an example. I know it is =
written that adding more Barium Carbonate will lead to the production of =
a mat surface. I wondered about this and ran a series of tests with up =
to 30% Barium Carbonate. Funny things happened, it did not behave as =
predicted. I got wonderful transparent glasses. Totally unbelievable, =
but I still have the evidence.
Yes, they use Silica and Alumina as an example of a Eutectic event in =
many of the books written about Glazing. But if you have been taught how =
to read Phase Equilibrium Diagrams you soon realise this is untrue, as =
described by you, and I quote ..."So it is possible to add two high =
melting point refactories silica and alumina together and the melting =
point will be lower than either of the lowest milting point of original =
materials...." If you study the Si02-Al2O3 phase diagram (Fig 314 in =
the Ref) you will see that the Eutectic point in this system is at =
1595=BAC and takes place between Mullite and Silica.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
John Britt on wed 7 dec 05
Hey Craig,
The only reason is because it costs about 30% more. ( I don't have a
catalogue handy but that is my recollection.)
You are right that alumina oxide works well, too. And with 35% LOI it
comes out about the same when comparing price with acutal alumina oxide. I
seem to remember that it is sometimes harder to get Alumina Oxide but
Highwater sells both here in NC.
Talk to you later,
John Britt
www.johnbrittpottery.com
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