Lili Krakowski on tue 1 jul 08
Someone wrote me off list to ask would I look at this glaze and see what it
is all about--as I did with Ann Griffin's.
As the person wrote off list I cannot use the name, suffice it to say it is
just as pretty a name as Ann Griffin. People with pretty names have glaze
problems apparently. (Yours truly, Wm of Ockham)
OK.
Here is the glaze and the addenda with it:
From:John B. Kenny "Ceramic Sculpture" page 163 Glaze #31 Black and Blue
Copper Cone 06-04 [Percent by weight]
Soda Ash-18
White Lead-30
Zinc Oxide-2
Feldspar-24
Flint-18
Tin Oxide-5
Copper Carbonate-2
Copper Oxide-1
I modified this slightly to remove the Copper Oxide and increase the Copper
Carbonate to 3 and got a very nice turquoise. Without the Copper
Carbonate/Copper Oxide it is a complex semi-matt opaque white. Increasing
the Copper Carbonate produces a deep green and if increased even more a
gunmetal.
Oy.
Let me say first that NOTHING replaces lead. When the Anti-Cholesterol
Lobby wants you to give up Whipped Cream and suggests putting skim milk
cream cheese and a bit of yoghurt in the blender and using that instead, or
similar disgusting concoctions--forget it. NO one who has EVER tasted
whipped cream will be fooled. A stray and starving cat might be Same with
lead glazes, although some are trying bismuth.
BUT LEAD IS DEADLY, AND LEAD CONTAINING FRITS, AND FRITTED LEAD, JUST AS
DEADLY. Yes in some countries lead frits and fritted lead are still
permitted and used, but that does NOT make the product safe! So just forget
lead.
Moreover, soda ash is water soluble. So that goes out. To be replaced by
a high soda frit: F 3110.
But when we took out the lead WE CHANGED THE INTRINSIC CHARACTER of the
glaze. There is no going back. Whatever we produce now we will not get the
look or characteristics of a lead glaze.
The best--as far as I have found--the closest is to insinuate a tiny bit, I
mean tiny, of yellow stain into a glaze. That still does not replicate lead,
but is at least within earshot.
So I will find some 04 glazes sans lead...but not till tomorrow, as the
Great Raccoon War still goes on, and two bags of cement await me.
Meanwhile: ALL NEWBIES. The first book you get is Monona Rossol's "The
Artist's Complete Health and Safety Guide" . And get the latest edition.
And look at it, study it, take it to heart, use it. And when you find old
recipes, in any of the books, check the ingredients in Rossol....Point being
that many materials we used to use we no longer do, for safety reasons. And
it is NOT the fault of those who wrote the old pottery books, it is that at
the time we "all" did not know what we know now. We smoked, ate lots of red
meat, tanned ourselves, and used lead, barium, antimony and such in the
studio.
Till tomorrow
Lili Krakowski
Be of good courage
Edouard Bastarache on tue 1 jul 08
Hello Lilli,
" Let me say first that NOTHING replaces lead.
Lilli"
Except Bismuth Oxide, I know some experts are working on this
problem to determine an exact subsitution.
Gis la revido
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
Canada
http://www.pshcanada.com/Toxicology.htm
http://pagesperso-orange.fr/smart2000/livres.htm
http://www.flickr.com/photos/30058682@N00/
http://www.flickr.com/photos/potier/20321056/
Ivor and Olive Lewis on wed 2 jul 08
I agree with Lili Krakowski concerning Lead. Yes there are Lead Frits
and compounded Lead silicate compounds that are prepared so that the
lead remains insoluble during the manufacturing stage to protect
industrial workers.
But once on the pot, testing is needed to determine the degree of lead
release. And, as I recall, additions of copper compounds to a Lead
bearing glaze enhance the ability of Lead to leach, especially into
acidic fruit drinks.
Well designed high Sodium oxide glazes can give the same optical
brilliance as a transparent Lead glaze, but not the same colour
response.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
May Luk on wed 2 jul 08
Hello Lili and Friends;
If 'newbies' have gone to take a glaze course, they would have learned abou=
t health and safety. *AND* they would learn about what the materials dos an=
d don'ts. Or does that only happen in an ideal world?=20
I grow weary with self-taught potters and their loosey goosey health and sa=
fety interpretations. I hear it from my friends too, over in England and he=
re in the US. This is my personal experience.
We've done this before. Frit with 10-15% clay and 10-15% flint makes maioli=
ca base glaze. Base glaze plus opacifier (tin) =3D white glaze. It is a mat=
ter of messing about with the colorants / opacifiers with Professor Line Bl=
end and his dust mask.
Here are some complete eyesores - My maiolica glaze test analysis. {http://=
www.flickr.com/photos/yamerica/132019576/in/set-72057594112447083/} The rec=
ipes can be found goggling "Linda Arbuckle". Lee sent me the list of recipe=
s, but I moved across the pond and now I can't find them.
Lead white glaze with copper - yummy!!=20
May {still a newbie}
Kings County, NY
=0A=0A=0A __________________________________________________________=
=0ANot happy with your email address?.=0AGet the one you really want - mill=
ions of new email addresses available now at Yahoo! http://uk.docs.yahoo.co=
m/ymail/new.html
Kim Hohlmayer on wed 2 jul 08
Okay, I didn't know I was opening a can of worms here. I learned about glazing from a potter with a masters degree in ceramics from Ohio State University. He took me under his wing and taught me the whole plot from aardvark to zymurgy. BUT, glazing has changed over the past twenty years. The chemistry that leads to glaze formulation has not changed but ingredients have. Who remembers when oxidation reds were made of cadmium and much like the Corvaire car of the 1960's unsafe at any temperature.
I know what materials are safe and what materials are unsafe. Just because the work I and a number of people do requires the use of commercial glazes does not make me either an idiot or a lousy artist or an uneducated one. Sometimes we just don't have time to reinvent the wheel.
I have been firing electric kilns for 20 years and at every cone from 021 to 10. I have been helping a friend fire his wood reduction ^6 kiln for the past year. He and I both know the basics of glaze chemistry and both still use commercial glazes. The guy I mentioned who ran the one program where the glazes did not fit the bodies knew glaze chemistry, mixed his own glazes and did not care about the fit or the safety issue. He would not even allow a warning put on the jar of wax resist that it was really latex and therefore a health hazard for people with latex allergies. He was off in his own little state of denial.
Would I like to take off and review glaze making at a workshop? Yes!!! And I will as soon as someone sends me enough money to go do that. Could I look all this up in my personal collection of books on pottery. Yes I would if I could spend four or five days digging through the hundreds of stacked and piled boxes that used to be my studio before I moved in Nov. of 2006, but right now there is no way to do that.
And yes, I could check the archives and will next time but it took me two months just to get into clayart and figure out how to post and send email.
No, I am not mad at anyone but I do think that sometimes we forget that it is easy to harder on people than is necessary. Open forums only stay open when we have room to speak without unneccessary rebuff. Besides that I don't mind May's public comments nearly as much as the person who sent the direct email essentially telling me to not clutter up the list with such a basic question. Anyway, sort of sorry for the rant. Thanks. --Kim H.
--- On Tue, 7/1/08, May Luk wrote:
> From: May Luk
> Subject: Re: Recalculating a lead glaze
> To: CLAYART@LSV.CERAMICS.ORG
> Date: Tuesday, July 1, 2008, 9:47 PM
> Hello Lili and Friends;
>
> If 'newbies' have gone to take a glaze course, they
> would have learned about health and safety. *AND* they would
> learn about what the materials dos and don'ts. Or does
> that only happen in an ideal world?
>
> I grow weary with self-taught potters and their loosey
> goosey health and safety interpretations. I hear it from my
> friends too, over in England and here in the US. This is my
> personal experience.
>
> We've done this before. Frit with 10-15% clay and
> 10-15% flint makes maiolica base glaze. Base glaze plus
> opacifier (tin) = white glaze. It is a matter of messing
> about with the colorants / opacifiers with Professor Line
> Blend and his dust mask.
>
> Here are some complete eyesores - My maiolica glaze test
> analysis.
> {http://www.flickr.com/photos/yamerica/132019576/in/set-72057594112447083/}
> The recipes can be found goggling "Linda
> Arbuckle". Lee sent me the list of recipes, but I
> moved across the pond and now I can't find them.
>
> Lead white glaze with copper - yummy!!
>
> May {still a newbie}
> Kings County, NY
>
>
>
>
> __________________________________________________________
> Not happy with your email address?.
> Get the one you really want - millions of new email
> addresses available now at Yahoo!
> http://uk.docs.yahoo.com/ymail/new.html
May Luk on thu 3 jul 08
Oh, hello again Kim;
If you don't have time, commercial glaze is the way to go. I asked this sam=
e question on Clayart in April 06: I wanted to formulate a leadless earthen=
ware glaze. I got a shed load of recipes (UK and US both) I tested a bunch =
of them with my friend. We didn't expect to and we didn't get anywhere quic=
kly. In short, no quick fix to your query because I have done it myself. I =
found the easiest way is to start from scratch.=20
I don't have a lot of time myself (nobody does!), therefore I need to work =
smart by spending more time on thinking. Oil is $140 a barrel a week ago. T=
ruck drivers in India and England are going on strike. Food prices going up=
because of petrol. More reasons to work smart and make good work and be ha=
rsh on ourselves.
"Glaze preparation is not a trivial process" (Eppler and Obstler, Understan=
ding Glazes)"How successful we will be in problem solving and in direct rel=
ationship to the time we spend thinking about the problem, our knowledge of=
the process and materials we use. (Ron Roy, Glaze Doctor Computer Course M=
anual)
Thanks for listening.
May
Kings County NY
P.S. Excellent information on lead and the do's and don'ts and the why not'=
s. Read Understanding Glazes by Richard A. Eppler with Mimi Obstler when yo=
u can get to it.
> From: Kim Hohlmayer
> Sometimes we just don't have time to reinvent the
> wheel.
> I have been firing electric kilns for 20 years and at
> every cone from 021 to 10. I have been helping a friend
> fire his wood reduction ^6 kiln for the past year. He and
> I both know the basics of glaze chemistry and both still
> use commercial glazes. =20
[...]=0A=0A=0A _______________________________________________________=
___=0ANot happy with your email address?.=0AGet the one you really want - m=
illions of new email addresses available now at Yahoo! http://uk.docs.yahoo=
.com/ymail/new.html
Doric T. Jemison-Ball ll on thu 3 jul 08
Dear Lila:
It's OK to use my name. I never thought of my name as particularly pretty.
And thanks for looking into this for me. I agree totally with your comments
regarding lead. In California, there are serious legal requirements and
restrictions regarding the use of lead [largely dealing with labeling and
disposal] that make it impractical to consider using.
Doric T.Jemison-Ball II
Gualala, CA
707-884-5067 Voice
818-606-6678 CELL
buffalo@bbs-la.com
"You can always cure the sausage that's too long"
Susan Gatherers
----- Original Message -----
From: "Lili Krakowski"
To:
Sent: Tuesday, July 01, 2008 6:52 AM
Subject: Recalculating a lead glaze
> Someone wrote me off list to ask would I look at this glaze and see what
> it
> is all about--as I did with Ann Griffin's.
> As the person wrote off list I cannot use the name, suffice it to say it
> is
> just as pretty a name as Ann Griffin. People with pretty names have glaze
> problems apparently. (Yours truly, Wm of Ockham)
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