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small problem, need advice

updated sun 29 oct 06

 

Bunny Lemak on sat 21 oct 06


Raku is strickly for decoration, you can not eat off of it, correct?
Actually I already know the answer is no you cannot eat off of it, so here
is my problem:

I am in charge of finding artists for an upcoming Cat/Art show at a local
cat shelter. This is an annual fundraiser for the shelter.

One artist who contacted me said she did Raku and makes kitty dishes and
platters and is willing to put some in the show.

Should I be bold and ask if these are for decoration or for food purposes,
then explain that Raku isn't suitable for food? Or....

should I just shut up and accpet what she is selling knowing that a
percentage is going to the shelter??

I don't want to come across as a "know-it-all" type, but then again I
don't want people to think they can eat off of Raku pieces safely either!!!

What would you do???

Bunny
In a quandry in sunny AZ.

Beth Spindler on sat 21 oct 06


She may just mean she does raku work AND makes kitty dishes, etc. (non raku).....I wouldn't hesitate to ask her.
Beth


-----Original Message-----
From: tlemak@COX.NET
To: CLAYART@LSV.CERAMICS.ORG
Sent: Sat, 21 Oct 2006 3:09 PM
Subject: Small problem, need advice


Raku is strickly for decoration, you can not eat off of it, correct?
Actually I already know the answer is no you cannot eat off of it, so here
is my problem:

I am in charge of finding artists for an upcoming Cat/Art show at a local
cat shelter. This is an annual fundraiser for the shelter.

One artist who contacted me said she did Raku and makes kitty dishes and
platters and is willing to put some in the show.

Should I be bold and ask if these are for decoration or for food purposes,
then explain that Raku isn't suitable for food? Or....

should I just shut up and accpet what she is selling knowing that a
percentage is going to the shelter??

I don't want to come across as a "know-it-all" type, but then again I
don't want people to think they can eat off of Raku pieces safely either!!!

What would you do???

Bunny
In a quandry in sunny AZ.

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Marta Matray on sat 21 oct 06


just because its raku, it doesnt mean it is poisonous!
for dry catfood, i would use it.
i am not a cat, but i have a rakufired dish i like to
put peanuts or almonds... or m&m candies.
ok, its not good for soup bowls or cereal bowls, but
whats wrong with putting catfood in it?

marta
(dont hate me because i like raku... :)

marta matray
rochester,mn
=============
http://www.mypots.com/Marta.htm
http://www.martamatray.com
http://www.angelfire.com/mn2/marta/

Russell Sheptak on sat 21 oct 06


Not exactly true. While many of the popular raku glazes are not
suitable for food (human or animal), this does not mean its impossible
to formulate and use, or even buy, a glaze that works at raku
temperatures that is food safe if fired properly.

There are two issues that I'm aware of, glaze stability and glaze fit.
Most of our favorite recipes for raku glazes are unstable; they have
too little silica and alumina to form a stable glaze that binds up the
oxides, so they end up leaching and changing color over time. Other
raku glazes are relatively stable in this regard, but craze (the
crackle glazes) because they don't fit the clay, and liquids soak
through them into the bisqueware and leach materials from the exterior
glaze and bisque. These crackle glaze lined vessels are usually fine
as containers for dry, non-acid foods.

There are stable glazes that can be used in raku that will be food
safe. John Hesselberth's frogpondpottery.com website posts the recipe
for a cone 04 liner glaze that he's had leach tested. That's a little
higher than most of my raku firings go, but the same principles could
be used to come up with a cone 06 version. There are also many
commercial cone 06 glazes that are marked as "food safe" and used in
raku. I would hope this person is using some of those glazes for
lining her petfood dishes.

I like my cats. I would ask about the glaze used as a liner on the
petfood dishes and how she knows its food safe. If they're for dry
food only, mark them that way. Have a good sale!

rus



On Oct 21, 2006, at 12:09 PM, Bunny Lemak wrote:

> Raku is strickly for decoration, you can not eat off of it, correct?
> Actually I already know the answer is no you cannot eat off of it, so
> here
> is my problem:
>
> I am in charge of finding artists for an upcoming Cat/Art show at a
> local
> cat shelter. This is an annual fundraiser for the shelter.
>
> One artist who contacted me said she did Raku and makes kitty dishes
> and
> platters and is willing to put some in the show.
>
> Should I be bold and ask if these are for decoration or for food
> purposes,
> then explain that Raku isn't suitable for food? Or....
>
> should I just shut up and accpet what she is selling knowing that a
> percentage is going to the shelter??
>
> I don't want to come across as a "know-it-all" type, but then again I
> don't want people to think they can eat off of Raku pieces safely
> either!!!
>
> What would you do???
>
> Bunny
> In a quandry in sunny AZ.
>
> _______________________________________________________________________
> _______
> 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.
>

Elizabeth Priddy on sat 21 oct 06


sell them with the caveat that they are for dry food
only. No water, no wet food.

You, yourself can eat jellybeans out of raku, you just
shouldn't eat the oatmeal.

Raku is food safe to serve bread but no butter.
muffins, but no pies.


She may already know and only intend them for dry
food, so you might ask her to label them accordingly.

E


Elizabeth Priddy

Beaufort, NC - USA
http://www.elizabethpriddy.com

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Craig Clark on sun 22 oct 06


Bunny, Russell, ........I do not know of any clay body that is sold
to the greater clay community that will vitrify at Raku temperatures.
Without a vitrified clay body there are several problems. There is not
much strength in a body that has not vitrified. Because of this the
ware, if used for functional purposes, may be damaged easily in general
use. Secondly, and perhaps more importantly, an unvitrified body is
still absorptive. Not a good idea when talking about food service.
Additionally, the very nature of the raku process puts an exceptional
stress on the glaze and clay body intentionally to bring about the
crackle effect that you have mentioned. I suspect that practically any
glaze, when subjected to the raku process will craze, whether a heavy
burn in reveals the crazing pattern or not, it will be there. My
question to folks is why use the raku process for functional work when
we know that there are such formidable issues to overcome? Raku is best
left for decorative effects.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 St
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org

Russell Sheptak wrote:
> Not exactly true. While many of the popular raku glazes are not
> suitable for food (human or animal), this does not mean its impossible
> to formulate and use, or even buy, a glaze that works at raku
> temperatures that is food safe if fired properly.
>
> There are two issues that I'm aware of, glaze stability and glaze fit.
> Most of our favorite recipes for raku glazes are unstable; they have
> too little silica and alumina to form a stable glaze that binds up the
> oxides, so they end up leaching and changing color over time. Other
> raku glazes are relatively stable in this regard, but craze (the
> crackle glazes) because they don't fit the clay, and liquids soak
> through them into the bisqueware and leach materials from the exterior
> glaze and bisque. These crackle glaze lined vessels are usually fine
> as containers for dry, non-acid foods.
>
> There are stable glazes that can be used in raku that will be food
> safe. John Hesselberth's frogpondpottery.com website posts the recipe
> for a cone 04 liner glaze that he's had leach tested. That's a little
> higher than most of my raku firings go, but the same principles could
> be used to come up with a cone 06 version. There are also many
> commercial cone 06 glazes that are marked as "food safe" and used in
> raku. I would hope this person is using some of those glazes for
> lining her petfood dishes.
>
> I like my cats. I would ask about the glaze used as a liner on the
> petfood dishes and how she knows its food safe. If they're for dry
> food only, mark them that way. Have a good sale!
>
> rus
>
>
>
> On Oct 21, 2006, at 12:09 PM, Bunny Lemak wrote:
>
>> Raku is strickly for decoration, you can not eat off of it, correct?
>> Actually I already know the answer is no you cannot eat off of it, so
>> here
>> is my problem:
>>
>> I am in charge of finding artists for an upcoming Cat/Art show at a
>> local
>> cat shelter. This is an annual fundraiser for the shelter.
>>
>> One artist who contacted me said she did Raku and makes kitty dishes
>> and
>> platters and is willing to put some in the show.
>>
>> Should I be bold and ask if these are for decoration or for food
>> purposes,
>> then explain that Raku isn't suitable for food? Or....
>>
>> should I just shut up and accpet what she is selling knowing that a
>> percentage is going to the shelter??
>>
>> I don't want to come across as a "know-it-all" type, but then again I
>> don't want people to think they can eat off of Raku pieces safely
>> either!!!
>>
>> What would you do???
>>
>> Bunny
>> In a quandry in sunny AZ.
>>
>> _______________________________________________________________________
>> _______
>> 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.
>

Lee Love on sun 22 oct 06


I once bought a latte bowl made by a local artist at Cafe Latte
in St. Paul. It come with a nice little brochure that explained the
French tradition of these functional bowls. This person inspired me
to make my own raku latte bowls. I used them for years and they are
in storage in Mpls. Going to start making them here.

I wonder if this could be an education opportunity with the
raku? Can the maker include an informational brochure.
--
Lee in Mashiko, Japan
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
"When we all do better. We ALL do better." -Paul Wellstone

claybair on sun 22 oct 06


Sheryl,
I would never consider using a raku bowl for the basin.
Line or seal away but you will never be sure that there isn't some hidden
crack that will eventually leak or leach water on the customer's antique
Loueee the XIIIIth
table. And then there you are with a irate customer bad mouthing you or
worse
suing you.
My advice....... make the basin out of stoneware with a stable ^6 glaze that
is
complementary to the raku pieces you use for the rest of the fountain.

Russell.......
Regarding your comment
"There are also many commercial cone 06 glazes that are marked as "food
safe" and used in raku."
Buyer beware......... many of the glazes which say "food safe" and "meets
FDA standards" .
For example.....Duncan Diamond Clear has 25+% lead in it.
Many of your "paint your own" shops use it. So there's little Betsy making
bowls for all her pets and family.
How sweet!
These glaze companies make that food safe claim are getting away with it
because the standards are antiquated (from 1970).
Today your average over the counter lead test kit is so much more sensitive
than the equipment used in 1970.
They will register a bright pink when applied to even the "correctly fired"
pieces with those glazes.
So the big thing to watch out for is the ingredients......

Gayle Bair
Bainbridge Island, WA
Tucson, AZ
http://claybair.com

-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Sheryl
McMonigal
Sent: Sunday, October 22, 2006 7:21 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Small problem, need advice


I have an added question to the raku problem. I am wondering if perhaps you
could do a lower cone clear glaze or colored glaze in the inside the before
rakuing that way it would be water proof on the inside. say raku is >06 and
maybe use >08 glaze for the inside. I have a client that wants me to make
fountains with my raku bowls.
sheryl mcmonigal
----- Original Message -----
From: "Russell Sheptak"
To:
Sent: Saturday, October 21, 2006 3:55 PM
Subject: Re: Small problem, need advice


> Not exactly true. While many of the popular raku glazes are not
> suitable for food (human or animal), this does not mean its impossible
> to formulate and use, or even buy, a glaze that works at raku
> temperatures that is food safe if fired properly.
>
> There are two issues that I'm aware of, glaze stability and glaze fit.
> Most of our favorite recipes for raku glazes are unstable; they have
> too little silica and alumina to form a stable glaze that binds up the
> oxides, so they end up leaching and changing color over time. Other
> raku glazes are relatively stable in this regard, but craze (the
> crackle glazes) because they don't fit the clay, and liquids soak
> through them into the bisqueware and leach materials from the exterior
> glaze and bisque. These crackle glaze lined vessels are usually fine
> as containers for dry, non-acid foods.
>
> There are stable glazes that can be used in raku that will be food
> safe. John Hesselberth's frogpondpottery.com website posts the recipe
> for a cone 04 liner glaze that he's had leach tested. That's a little
> higher than most of my raku firings go, but the same principles could
> be used to come up with a cone 06 version. There are also many
> commercial cone 06 glazes that are marked as "food safe" and used in
> raku. I would hope this person is using some of those glazes for
> lining her petfood dishes.
>
> I like my cats. I would ask about the glaze used as a liner on the
> petfood dishes and how she knows its food safe. If they're for dry
> food only, mark them that way. Have a good sale!
>
> rus
>
>
>
> On Oct 21, 2006, at 12:09 PM, Bunny Lemak wrote:
>
> > Raku is strickly for decoration, you can not eat off of it, correct?
> > Actually I already know the answer is no you cannot eat off of it, so
> > here
> > is my problem:
> >
> > I am in charge of finding artists for an upcoming Cat/Art show at a
> > local
> > cat shelter. This is an annual fundraiser for the shelter.
> >
> > One artist who contacted me said she did Raku and makes kitty dishes
> > and
> > platters and is willing to put some in the show.
> >
> > Should I be bold and ask if these are for decoration or for food
> > purposes,
> > then explain that Raku isn't suitable for food? Or....
> >
> > should I just shut up and accpet what she is selling knowing that a
> > percentage is going to the shelter??
> >
> > I don't want to come across as a "know-it-all" type, but then again I
> > don't want people to think they can eat off of Raku pieces safely
> > either!!!
> >
> > What would you do???
> >
> > Bunny
> > In a quandry in sunny AZ.
> >
> > _______________________________________________________________________
> > _______
> > 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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Snail Scott on sun 22 oct 06


At 03:09 PM 10/21/2006 -0400, you wrote:
>...One artist who contacted me said she did Raku and makes kitty dishes and
>platters and is willing to put some in the show.


Dry foods like pet-food kibble
would be fine, but soft food
might cause a change in a metallic
interior glaze. I don't know how
sensitive our short-lived pets are
to metal oxide leaching, but
if the interior isn't a copper
glaze, it should be just fine. The
difficulties with raku tableware
are partly that the appearance
can change, and that the porous
clay and crazing can allow leakage
and bacterial growth, in addition
to the oxide-leaching issue. Raku
also microwaves badly, but most
people don't nuke pet food.

For pet dishes, I wouldn't use
raku for a water dish, but a food
bowl with no copper on the inside
seems pretty much OK to me. Should
be OK with copper, too, if dry
food only. Might be OK with wet
food too, but not sure. Hand
washing with no prolonged soaking
should make bacterial growth no
huge concern. Besides, I know
what my critters eat (and eat
off of) outdoors. Can raku really
be worse?

-Snail

Nancy Braches on sun 22 oct 06


I would be concerned with that customer who buys the piece, puts the water or moist food in it and then something happens to poor kitty. Next thing you know, that customer is blaming the shelter who put up the show because it was their responsibility to sell "safe" products. All in all...how important is the percetage going to the good cause when compared to being sued. Raku...safe or not...hard to sell in any case as a "functional" piece of pottery. I'd lean more toward the safer side, have the artist mark them on the bottom as "safe for dry foods only" or not sell them. Many animal lovers think of their precious ones as their children and though not everyone thinks that way about animals, that one person can cause a lot of problems. Just my .02 on the issue.

Nancy

Snail Scott wrote: At 03:09 PM 10/21/2006 -0400, you wrote:
>...One artist who contacted me said she did Raku and makes kitty dishes and
>platters and is willing to put some in the show.


Dry foods like pet-food kibble
would be fine, but soft food
might cause a change in a metallic
interior glaze. I don't know how
sensitive our short-lived pets are
to metal oxide leaching, but
if the interior isn't a copper
glaze, it should be just fine. The
difficulties with raku tableware
are partly that the appearance
can change, and that the porous
clay and crazing can allow leakage
and bacterial growth, in addition
to the oxide-leaching issue. Raku
also microwaves badly, but most
people don't nuke pet food.

For pet dishes, I wouldn't use
raku for a water dish, but a food
bowl with no copper on the inside
seems pretty much OK to me. Should
be OK with copper, too, if dry
food only. Might be OK with wet
food too, but not sure. Hand
washing with no prolonged soaking
should make bacterial growth no
huge concern. Besides, I know
what my critters eat (and eat
off of) outdoors. Can raku really
be worse?

-Snail

______________________________________________________________________________
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/

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Nancy
Hilltop Pottery

http://pg.photos.yahoo.com/ph/hilltoppottery/album?.dir=/e4e8re2&.src=ph

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Alex Remon on sun 22 oct 06


>
>She may already know and only intend them for dry
>food, so you might ask her to label them accordingly.
>

Hi,

Kitty shelter employee here.

Any dishes that are not good for wet food should not be used for dry food
for kitties (or dogs) either. There is a lot of saliva generated when a
kitty eats and they lick near their food to pick it up. The kitties will
be licking the bowls thus picking up any toxins that would leach into
water or wetfood.

I would recommend that you ask her what kind of markings she puts on the
raku dishes to inform customers that they are not intended for food. By
asking this, she will either have an answer, or will say they are intended
for food. Then you can play dumb and say but it was my understanding that
raku glazes are toxic, and let her explain what makes her dishes food
safe. If she can't, you've either now gently informed her that she's
poisoning the poor things, or you've learned a new process for raku that's
foodsafe. Win win.

Alex

Sheryl McMonigal on sun 22 oct 06


I have an added question to the raku problem. I am wondering if perhaps you
could do a lower cone clear glaze or colored glaze in the inside the before
rakuing that way it would be water proof on the inside. say raku is >06 and
maybe use >08 glaze for the inside. I have a client that wants me to make
fountains with my raku bowls.
sheryl mcmonigal
----- Original Message -----
From: "Russell Sheptak"
To:
Sent: Saturday, October 21, 2006 3:55 PM
Subject: Re: Small problem, need advice


> Not exactly true. While many of the popular raku glazes are not
> suitable for food (human or animal), this does not mean its impossible
> to formulate and use, or even buy, a glaze that works at raku
> temperatures that is food safe if fired properly.
>
> There are two issues that I'm aware of, glaze stability and glaze fit.
> Most of our favorite recipes for raku glazes are unstable; they have
> too little silica and alumina to form a stable glaze that binds up the
> oxides, so they end up leaching and changing color over time. Other
> raku glazes are relatively stable in this regard, but craze (the
> crackle glazes) because they don't fit the clay, and liquids soak
> through them into the bisqueware and leach materials from the exterior
> glaze and bisque. These crackle glaze lined vessels are usually fine
> as containers for dry, non-acid foods.
>
> There are stable glazes that can be used in raku that will be food
> safe. John Hesselberth's frogpondpottery.com website posts the recipe
> for a cone 04 liner glaze that he's had leach tested. That's a little
> higher than most of my raku firings go, but the same principles could
> be used to come up with a cone 06 version. There are also many
> commercial cone 06 glazes that are marked as "food safe" and used in
> raku. I would hope this person is using some of those glazes for
> lining her petfood dishes.
>
> I like my cats. I would ask about the glaze used as a liner on the
> petfood dishes and how she knows its food safe. If they're for dry
> food only, mark them that way. Have a good sale!
>
> rus
>
>
>
> On Oct 21, 2006, at 12:09 PM, Bunny Lemak wrote:
>
> > Raku is strickly for decoration, you can not eat off of it, correct?
> > Actually I already know the answer is no you cannot eat off of it, so
> > here
> > is my problem:
> >
> > I am in charge of finding artists for an upcoming Cat/Art show at a
> > local
> > cat shelter. This is an annual fundraiser for the shelter.
> >
> > One artist who contacted me said she did Raku and makes kitty dishes
> > and
> > platters and is willing to put some in the show.
> >
> > Should I be bold and ask if these are for decoration or for food
> > purposes,
> > then explain that Raku isn't suitable for food? Or....
> >
> > should I just shut up and accpet what she is selling knowing that a
> > percentage is going to the shelter??
> >
> > I don't want to come across as a "know-it-all" type, but then again I
> > don't want people to think they can eat off of Raku pieces safely
> > either!!!
> >
> > What would you do???
> >
> > Bunny
> > In a quandry in sunny AZ.
> >
> > _______________________________________________________________________
> > _______
> > 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.

Lee Love on mon 23 oct 06


On 10/23/06, Sheryl McMonigal wrote:

> maybe use >08 glaze for the inside. I have a client that wants me to make
> fountains with my raku bowls.
> sheryl mcmonigal

Sheryl,

I use TAK Fat white and have made water tight vases with it.
This is a beautiful glaze in post firing reduction and is the
closest thing I can find in low fire to a Hagi or Shino glaze. When
you resist decorate, the contrast between the white glaze and the
reduced black body is striking. It also takes copper decoration
well

I believe what is hardest on the integrity of the clay
body and glaze is putting the work in quenching water. It is where
the most thermal shock happens. If you reduce and let the pot cool
at room temp, you have a better chance of the pot not leaking.

Just came back from my supply store and bought a bag of red
raku clay. I have got TAK fat white working with Japanese materials.
You can see my experiments here from a couple years ago. The
crawling is identical to Shino and Hagi:

http://public.fotki.com/togeika/science/tak1.html

Tak Fat White Raku Glaze Comments: A Kurt Wild glaze, it came from a
student named Takahara.

Fat white, big crackle Give it time to cool just a second/deep reduction

frit 3134 100
silica 6 epk 10
tin or opax 10 If you want a clear leave this out. Bentonite will help
suspend it.

Takes copper well: blue/green to red/blood . Variations -- Takes
copper well Leave out tin for clear

Do some tests sans water quenching.

--
Lee in Mashiko, Japan
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
"When we all do better. We ALL do better." -Paul Wellstone

Craig Clark on mon 23 oct 06


Lee, there is no misunderstanding on my part. I'm fully aware that
low fired ware is not vitrified, though will not say never. I suspect
that given a proper lab and a good ceramic chemist one could design a
clay body that would vitrify at low fire temps. The problem is that it
would be so expensive as to be cost prohibitive for a potters use.I
can't really say for sure one way or the other.
I am not refering to a traditional tea ceremony or the making of tea
cups. It is not something toward which I aspire and claim little
knowledge thereof, other than appreciating the idea of the tea ceremony
from a potters perspective. I also understand what you are refering to
as "the insulating properties" of the clay. Once again, this was not
what I was talking about. I was making specific reference to what you
have emphasized in "....depends upon the glaze in terms of resisting
moisture." This is my point.....
I do not think that this is a very good idea to rely on the glaze to
resist the absorption of moisture. It is my belief that one ought to
strive for a vitrified clay body as well as a glaze that fits the body
well. This is what I now practice. I do not pretend it is the end all or
be all. I tell folks not to use Raku for functional purposes for the
reasons that I outlined. I stand by my reasoning. If someone wants to
use Raku for functional purposes then that is indeed their choice. I
just don't think it is particularly wise one.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 St
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org

Lee Love wrote:
> On 10/23/06, Craig Clark wrote:
>> Bunny, Russell, ........I do not know of any clay body that is sold
>> to the greater clay community that will vitrify at Raku temperatures.
>
> This is a misunderstanding about all low-fire ware. Low fired
> ware is never vitrified.(it is a deffinition of "earthen ware".) It
> always depends upon the glaze in terms of resisting moisture.
>
> One of the special attributes of raku for use in ceremonial
> tea is, because it is not vitrified, the clay body has insulating
> properties. This gives it a special feel in the hands in use.
>
> Original shino is similar. The clays used in mino shino
> ware do not vitrify at the glaze fire temps, but at much higher temps.
> Like cone 13 to 14. Also, the tea bowls are usually not fully
> glazed on the bottom. The bare clay on Shino tea bowls I have
> handed feel like bisque ware. They say because of this, you can
> "taste" the clay.
>
>> Raku is best left for decorative effects.
>
> Original raku teabowls are only used as functional ware, to
> serve matcha wisked tea in. They can be used safely when used in
> their original funcitons.
>
> --
> Lee in Mashiko, Japan
> http://potters.blogspot.com/
> "Let the beauty we love be what we do." - Rumi
> "When we all do better. We ALL do better." -Paul Wellstone
>
> ______________________________________________________________________________
>
> 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.
>

Snail Scott on mon 23 oct 06


At 09:01 PM 10/22/2006 -0400, Alex S wrote:
>Any dishes that are not good for wet food should not be used for dry food
>for kitties (or dogs) either. There is a lot of saliva generated when a
>kitty eats and they lick near their food to pick it up. The kitties will
>be licking the bowls thus picking up any toxins that would leach into
>water or wetfood.



A very good point about animal spit.

Raku doesn't always have to mean
copper-flash glazes, though. A nice
white crackle, or clear over a slip
design, or amber and other non-
copper glazes would be non-toxic
even when licked. Copper on the outer
non-food surface should be OK for
cats.

-Snail

Lee Love on mon 23 oct 06


On 10/23/06, Craig Clark wrote:
> Bunny, Russell, ........I do not know of any clay body that is sold
> to the greater clay community that will vitrify at Raku temperatures.

This is a misunderstanding about all low-fire ware. Low fired
ware is never vitrified.(it is a deffinition of "earthen ware".) It
always depends upon the glaze in terms of resisting moisture.

One of the special attributes of raku for use in ceremonial
tea is, because it is not vitrified, the clay body has insulating
properties. This gives it a special feel in the hands in use.

Original shino is similar. The clays used in mino shino
ware do not vitrify at the glaze fire temps, but at much higher temps.
Like cone 13 to 14. Also, the tea bowls are usually not fully
glazed on the bottom. The bare clay on Shino tea bowls I have
handed feel like bisque ware. They say because of this, you can
"taste" the clay.

> Raku is best left for decorative effects.

Original raku teabowls are only used as functional ware, to
serve matcha wisked tea in. They can be used safely when used in
their original funcitons.

--
Lee in Mashiko, Japan
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
"When we all do better. We ALL do better." -Paul Wellstone

Heather Pedersen on mon 23 oct 06


Every time this issue comes up, I go look and see if I can find ANYTHING
relating to food safety and tableware/ceramics/pottery and porosity. I
have found a single regional restriction that restaurants (and only
restaurants) cannot use porous tableware.

As near as I have been able to find, the only thing that the law cares
about is levels for leachable lead and cadmium, and then many, many
regulations relating to how the food is prepared.

So, as long as the raku isn't poisonous (no lead, no cadmium), it is food
safe.

Unless someone can find some actual data/information from a reputable
source in the food safety industry saying otherwise, I consider allegations
that raku is not food safe because it is porous to be old wives tales with
no basis in fact.

So, I would accept the raku cat dishes and not even bat an eyelash.

Regards,


-= Heather Pedersen



On Sat, 21 Oct 2006 15:09:09 -0400, Bunny Lemak wrote:

>Raku is strickly for decoration, you can not eat off of it, correct?
>Actually I already know the answer is no you cannot eat off of it, so here
>is my problem:
>
>I am in charge of finding artists for an upcoming Cat/Art show at a local
>cat shelter. This is an annual fundraiser for the shelter.
>
>One artist who contacted me said she did Raku and makes kitty dishes and
>platters and is willing to put some in the show.
>
>Should I be bold and ask if these are for decoration or for food purposes,
>then explain that Raku isn't suitable for food? Or....
>
>should I just shut up and accpet what she is selling knowing that a
>percentage is going to the shelter??
>
>I don't want to come across as a "know-it-all" type, but then again I
>don't want people to think they can eat off of Raku pieces safely either!!!
>
>What would you do???
>
>Bunny
>In a quandry in sunny AZ.
>
>___________________________________________________________________________
___
>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.

Snail Scott on mon 23 oct 06


At 07:20 PM 10/22/2006 -0700, you wrote:
>I have an added question to the raku problem. I am wondering if perhaps you
>could do a lower cone clear glaze or colored glaze in the inside the before
>rakuing that way it would be water proof on the inside.


It's not just the glaze that causes
crazing and thus leaks- it's also the
thermal shock of the usual raku
process. Even if you had a good glaze
layer form a previous firing - and any
temperature glaze could potentially
produce that - re-firing it as raku
(pulling it from the kiln while still
hot) will make that glaze craze.

Additionally, most raku clay bodies are
made resistant to the stresses of thermal
shock by being undervitrified, and many
so-called raku clays are really just
higher-temperature clays, relabeled.
Any glaze applied to such an underfired
body will eventually craze, especially
after the clay gets wet.

For non-food purposes, penetrating
sealants seem to have potential, but I
woudn't rely on these for foodware.

-Snail

Lee Love on wed 25 oct 06


On 10/24/06, Craig Clark wrote:
> Lee, there is no misunderstanding on my part.

Craig, you were singling out raku,. It is earthenware and one
of the definitions of earthenware is that it is not vitrified.

I have ONLY made functional raku. The way to achieve it is
based upon the same principles for any earthenware, combined with no
quenching of the pots in water.

Many of the warnings about glaze crazing etc, is primarily
important related to earthenware, because as long as you are beginning
with safe materials, you are not going to have a lot of trouble with
stoneware because the body is vitrified. Several of my stoneware
bodies do not require any glaze at all and work as functional pottery.
This is not true for most Earthernware (yes, there are exceptions,
like terrasig burnished redware.) Matt surfaced raku is where
trouble comes into play for functional ware.

> clay body that would vitrify at low fire temps. The problem is that it
> would be so expensive as to be cost prohibitive for a potters use.I
> can't really say for sure one way or the other.

With enough money you can do just about anything. But we are
talking about what we generally think of as being earthenware. As I
mentioned previously, there are exceptions to stoneware being
vitrified, as in the case of Mino Shino. If you vitrified
earthenware, you would loose the characteristics that make it unique.
You would end up with the worst of both worlds.


> I am not refering to a traditional tea ceremony or the making of tea
> cups. It is not something toward which I aspire and claim little
> knowledge thereof, other than appreciating the idea of the tea ceremony

It is the only true raku . I dont make majolica, but I know
very well that it is earthenware than can be used with food.

Many of the mat surfaced, post reduction raku wares made
in America are not usable as functional ware. That is the best way
to explain it. But also, you might question if this American work is
really raku? It isnt recognized as such here. It will be
interesting when I start showing my TAK Fat White tea bowls here in
Japan. They might not pass as Raku either.

> what I was talking about. I was making specific reference to what you
> have emphasized in "....depends upon the glaze in terms of resisting
> moisture." This is my point.....

The insulating qualites can have a function as well as the shock
resistance when used in traditional flameware. Non-vitirfied clay
has its purposes. Hey, did you know in India that the traditional
teapot and cup used on the railroad were not fired at all? Because
of this, they could be tossed out the window and the clay simply
returned to the earth after use.

> well. This is what I now practice. I do not pretend it is the end all or
> be all. I tell folks not to use Raku for functional purposes for the
> reasons that I outlined. I stand by my reasoning. If someone wants to
> use Raku for functional purposes then that is indeed their choice. I
> just don't think it is particularly wise one.

I understand. I think the specific problems of
earthenware should be explained and understood. It is better, I
think, to explain the qualities of the work and then let people decide
on their own. That was my advice to the original person who posted
the question.

I really like functional raku. Recently, there was a teabowl on
Nan Demo Kan Tai Den, that was valued at a quarter milllion dollars!
One of my favorite functional potters is Linda Arbuckle. Her
majolica earthenware is very functional.

Check out Tom Hess s unglazed redware pie plates

http://www.hesspottery.com/pie_plates.htm

He got a big break with an article in the New York Times advertising him

http://www.nytimes.com/2003/12/10/dining/10PLAT.html?ex=1386392400&en=00f5f372f7e5cbe7&ei=5007&partner=USERLAND
--
Lee in Mashiko, Japan
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
"When we all do better. We ALL do better." -Paul Wellstone

Ron Roy on sat 28 oct 06


Hi Heather,

I do think there are potential problems.

Ware that is porous will have some water in it after use and washing for
instance - microwave that and the pot can get very hot.

What happens when liquid food is absorbed? - does it go bad? - is that a
problem if more food is stored in that pot? What happens if food is heated
in that pot and the old food comes out of the pot into the new food.

I would say that we are used to using ware that is not porous now and we
don't realize what the problems can be - so perhaps there should be some
kind of warning about porous pots and how they should be used.

By the way there are legal limits on other heavy metals leaching in other
countries - surely you don't mean that anything is OK?

RR


>Every time this issue comes up, I go look and see if I can find ANYTHING
>relating to food safety and tableware/ceramics/pottery and porosity. I
>have found a single regional restriction that restaurants (and only
>restaurants) cannot use porous tableware.
>
>As near as I have been able to find, the only thing that the law cares
>about is levels for leachable lead and cadmium, and then many, many
>regulations relating to how the food is prepared.
>
>So, as long as the raku isn't poisonous (no lead, no cadmium), it is food
>safe.
>
>Unless someone can find some actual data/information from a reputable
>source in the food safety industry saying otherwise, I consider allegations
>that raku is not food safe because it is porous to be old wives tales with
>no basis in fact.
>
>So, I would accept the raku cat dishes and not even bat an eyelash.
>
>Regards,
>
>
>-= Heather Pedersen

Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0