Mel Jacobson on sat 9 may 98
is almost always army green.
ick.
david hendley is very smart. i always take his advice.
some things just can't be re/used. well, unless you
really don't care what your pots look like.
however, i do save all of my rutile glazes, have about 40 gallons..
use it as an underglaze for my base rhodes 32...works all of the time.
but it is basically the same glaze.
p.s. hint no. 2,356
i have a nice kitchen strainer mounted to a long handle....use it to
stir glazes...you cannot imagine what it picks up each time.
i use a really small one with fine mesh to stir oxides and fine glazes.
just use it every time...always picks up crap, pieces that drop from
pots....just stuff.
mel/mn
http://www.pclink.com/melpots
Paul Lewing on fri 24 mar 06
on 3/24/06 8:07 PM, mel jacobson at melpots2@pclink.com wrote:
> why would anyone want to apply scrap/unknown
> glazes to good pots? it just does not make sense.
> after a few years of taking army green pots from a kiln
> will teach folks to dump scrap/unknown, mystery
> glazes.
> penny wise, pound foolish.
I have to disagree with you on this one, Mel. While you do have a point
that most scrap glaze is army green (oddly enough, it's almost exactly the
same color in reduction and oxidation) it doesn't have to stay that way.
I use all the scrap glaze I generate in my studio, but I use almost none of
it alone. I add more colorant to make a black, I mix it half and half with
an opaque white to get a gray almost like celadon, I mix it half and half
with a clear and add copper and cobalt to get a brilliant green. I've added
tin and gotten purple. I've added titanium and gotten an effect like a
rutile blue. Used this way, it's no more an unknown quantity than wood ash
or local clay. For me, anyway, it's remarkably consistent from batch to
batch over many years.
It's true that using something ugly because it saves you money is foolish,
it's also foolish to throw away something that you can make something
beautiful out of. I find that some of my scrap based glazes have a
complexity and depth to them I can't easily get otherwise in oxidation
glazes. I happen to like a really clear intense cobalt blue, but if you
don't, a little scrap glaze added can tone it down nicely.
I once kept two scrap batches for awhile- one that had all my iron glazes,
and one that had only glazes with no iron. The one I called Nofe (as in No
Fe) was the most gorgeous robin's egg blue you've ever seen. I was never
able to repeat it, but who cares? I wasn't making open stock dinnerware.
The iron one, by the way, just kept getting a darker and uglier army green.
All it takes is (you guessed it) MORE TESTING!
Paul Lewing
mel jacobson on fri 24 mar 06
that is what it is:
scrap. (junk)
i think making good pots, having great bisque ware
is vital to a studio.
why would anyone want to apply scrap/unknown
glazes to good pots? it just does not make sense.
it would prove you have no sense of value for your work.
a few cents worth of glaze materials is not worth it.
after a few years of taking army green pots from a kiln
will teach folks to dump scrap/unknown, mystery
glazes.
penny wise, pound foolish.
i have preached this for years....usually getting
very silly arguments in return. `i am learning something
with the use of scrap.` what? that junk, unknown entities
are good? you can ruin very good, well made pots with crap glaze?
same when you find a bag of white stuff, unmarked
in your glaze area. throw it out.
get rid of it.
do you think you can taste it...`hmm, seems to have a ginger
flavor, must be silica`.
it is hard enough to make great pots when you have a
really fine, well compounded known glaze. why use junk.
mel
"Luck is prepaid."
from: mel/minnetonka.mn.usa
website: http://my.pclink.com/~melpots3
John Post on sat 25 mar 06
Other than making the usual army green color, there is another problem
with scrap glazes.
When you start dumping glazes made of many different materials into one
bucket, you are increasing the variety of fluxes in the glaze. When you
have a glaze that has 10 or 15 different types of flux materials in it,
you have just lowered it's firing temperature by a couple of cones at
least. This glaze then runs off the pots and makes a mess for you to
clean up on all of your kiln shelves. So in order to save a few cents
of materials, you ruin some pots and then have to chisel and grind your
kiln shelves.
I think it was David Hendley who said that he just takes a cup of his
scrap glaze and mixes it into his clay when he is making it as a way to
dispose of the material.
John Post
Sterling Heights, Michigan
Paul Lewing on sat 25 mar 06
on 3/25/06 6:27 AM, John Post at johnpost@WIDEOPENWEST.COM wrote:
> When you start dumping glazes made of many different materials into one
> bucket, you are increasing the variety of fluxes in the glaze. When you
> have a glaze that has 10 or 15 different types of flux materials in it,
> you have just lowered it's firing temperature by a couple of cones at
> least. This glaze then runs off the pots and makes a mess for you to
> clean up on all of your kiln shelves.
Not in my experience, John. I don't think there are too many people who use
more different and varied glazes than I do, and my scrap always matures at
the same temperature as all the other glazes I use. Logically what you say
makes sense, but I've never seen it work that way.
Paul Lewing
Vince Pitelka on sat 25 mar 06
John Post wrote:
"When you start dumping glazes made of many different materials into one
bucket, you are increasing the variety of fluxes in the glaze. When you
have a glaze that has 10 or 15 different types of flux materials in it, you
have just lowered it's firing temperature by a couple of cones at least.
This glaze then runs off the pots and makes a mess for you to clean up on
all of your kiln shelves."
John -
Where do you get this information? I have never seen this happen. I don't
generally use mixes of scrap glazes any more, but I have many times in the
past. When you combine scrap glazes you are not increasing the overall
proportion of flux, and thus you are not lowering the firing temperature.
Among the reasons why it is desirable to have a variety of fluxes in a
glaze, it usually broadens the firing range, making a more versatile glaze.
It would not make the glazes run more than what would be expected from an
average of the combined glazes.
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Earl Brunner on sat 25 mar 06
I remember the post about putting some scrap or discard
glaze into the clay mixer, works good. However, if you
adjust the scrap like Paul Lewing suggested, then the
running shouldn't be a problem either.
Earl Brunner
Las Vegas, NV
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On
Behalf Of John Post
Sent: Saturday, March 25, 2006 6:28 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: scrap glaze
Other than making the usual army green color, there is
another problem
with scrap glazes.
When you start dumping glazes made of many different
materials into one
bucket, you are increasing the variety of fluxes in the
glaze. When you
have a glaze that has 10 or 15 different types of flux
materials in it,
you have just lowered it's firing temperature by a
couple of cones at
least. This glaze then runs off the pots and makes a
mess for you to
clean up on all of your kiln shelves. So in order to
save a few cents
of materials, you ruin some pots and then have to
chisel and grind your
kiln shelves.
I think it was David Hendley who said that he just
takes a cup of his
scrap glaze and mixes it into his clay when he is
making it as a way to
dispose of the material.
John Post on sat 25 mar 06
Before I started using glaze calculation and Currie grids to develop
glazes, I used what I now call the shotgun approach.
I would test glazes from everywhere looking for ones that I found
interesting at cone 6 oxidation.
I would either hit the target or be way off.
As a result of this method I had many 300 gram batches of leftover dud
glazes.
I would dump all of these into a 5 gallon bucket and then test it to see
what the glaze looked like.
Most times, the glaze would be more runny and tend to mature at a
temperature lower than cone 6.
I think the relevant thing in my experience is that the glazes made
using the shotgun approach to testing were made from a wide variety of
ceramic materials.
I didn't just have one feldspar and some whiting and Gerstley in that
combined bucket.
I had a wide variety of materials in that bucket...
3 or more different frits (3134, 3124, 3110)
3 different types of feldspars (custer, neph sy, kona)
whiting
wollastonite
cornwall stone
bone ash
barium
strontium
etc...
Because of this I came to the conclusion that the reason my scrap glazes
were runny was because the fluxes were so varied.
Now that I work in a more narrow vein when it comes to approaching glaze
development I guess that if I had a scrap bucket it would tend to be
less runny since the fluxes would not be so diverse.... but now I just
mix the small amount of scrap generated during testing into my clay.
Anyway, my theory about the scrap glazes firing at a lower temperature
is based on my personal experiences in mixing and firing a wide variety
of diverse base glazes to cone 6.
John Post
Sterling Heights, Michigan
Vince wrote:
> When you combine scrap glazes you are not increasing the overall
> proportion of flux, and thus you are not lowering the firing temperature.
> Among the reasons why it is desirable to have a variety of fluxes in a
> glaze, it usually broadens the firing range, making a more versatile
> glaze.
> It would not make the glazes run more than what would be expected from an
> average of the combined glazes.
Donna Kat on sun 26 mar 06
On Fri, 24 Mar 2006 22:07:33 -0600, mel jacobson wrote:
>that is what it is:
>scrap. (junk)
>
>i think making good pots, having great bisque ware
>is vital to a studio.
>
>why would anyone want to apply scrap/unknown
>glazes to good pots? it just does not make sense.
>it would prove you have no sense of value for your work.
>
>a few cents worth of glaze materials is not worth it.
>
>after a few years of taking army green pots from a kiln
>will teach folks to dump scrap/unknown, mystery
>glazes.
>penny wise, pound foolish.
In a university crafts studio very few of the pots made by the beginning
student would fall into the category of good pots. What you are doing for
the most part is using pots (that should never have been bisqued fired in
the first place by skilled potters) to learn about the techniques of glazing
and to have as keep sakes. Our students for the most part are doing this as
a means of relaxing and getting away from the stresses of college life.
They do want a memento of all their work and the experience however. Some
are willing to take the risk to see what surprise they will get. It is akin
to doing a reduction firing with a copper or iron glaze. You may get a
gorgeous red, blue or green - you may get a gag me with a spoon puke color.
We in general keep the mystery glaze in the same family of color and many
of our bases are the same so what you are playing with is the proportions of
cobalt, copper, rutile and iron. We just do oxidation firings so this is
our biggest surprise element. Those who are skilled potters in general
don't play around with the 'mystery' glaze - that is until someone's pot
comes out with a color that everyone envies. It would be a risky thing to
do in a production studio where you glazed many pots without know what the
outcome would be. I know of no one that would do that. It has been done in
every studio that I have been (college student studios).
Bob Masta on sun 26 mar 06
I am completely mystified why folks who wouldn't
want to put scrap glaze on a pot would mix in into
their clay! Sure, maybe you can reduce the proportion
enough so it won't be noticed... but then, you could
say that about mixing it into your drinking water.
What's wrong with using it as a glaze? Nobody is
saying "gosh, I've got a kiln-load of pots that I spent
days making, so I'll just dip 'em all in the mystery
glaze and cross my fngers". Of course not! You
test the scrap glaze on a few tiles and go from there.
People complain that they can't duplicate it because
they don't know its formula. Well, the only reason you'd
want to duplicate it is if it came out wonderful. Are
you saying that it's better to never have even seen a wonderful
glaze if you can't duplicate it? Heck, don't bother to fall
in love with a person either... what if the feeling doesn't
last? Sheesh!
Where is the artist's spirit of adventure? Give it a try;
what have you go to lose?
Best regards,
Bob Masta
potsATdaqartaDOTcom
John Hesselberth on sun 26 mar 06
> John Post wrote:
> "When you start dumping glazes made of many different materials
> into one
> bucket, you are increasing the variety of fluxes in the glaze.
> When you
> have a glaze that has 10 or 15 different types of flux materials in
> it, you
> have just lowered it's firing temperature by a couple of cones at
> least.
> This glaze then runs off the pots and makes a mess for you to clean
> up on
> all of your kiln shelves.
I have seen this happen when experimenting with layering glazes. The
overlap area is frequently significantly more fluid than the areas
where the two glazes are by themselves on the surface of the pot. It
doesn't always happen, but it sure can. I haven't taken the time to
try to define it more carefully, but I think it happens when the two
glazes have quite different fluxing systems. If you use very similar
base glazes you probably won't see it.
Regards,
John
Gayle Bair on sun 26 mar 06
I think the best response so far was using scrap glaze to make tiles.
I have a bucket that is about 10 years old and will now have a useful
purpose.
Gayle Bair
Bainbridge Island, WA
Tucson, AZ
www.claybair.com
-----Original Message-----
From: Bob Masta
I am completely mystified why folks who wouldn't
want to put scrap glaze on a pot would mix in into
their claysnip>
What's wrong with using it as a glaze? snip>
Paul Lewing on sun 26 mar 06
on 3/25/06 7:32 PM, John Post at johnpost@WIDEOPENWEST.COM wrote:
> Anyway, my theory about the scrap glazes firing at a lower temperature
> is based on my personal experiences in mixing and firing a wide variety
> of diverse base glazes to cone 6.
OK, John. That has not been my experience, even when testing lots of very
dissimilar glazes, but if that's what happened to you, there's no arguing
with it.
Paul Lewing
sharonia628 on sat 21 aug 10
I have seen these glazes labeled as GOK glaze (god only knows), WONDER glaz=
e
(as, I wonder what's in it) etc.
I remember Pete Pinnell telling us this story in a workshop:
He was working in Kansas City at the time, and the studio had a big vat of
this scrap glaze. He got to work on it, adding this and that, until it came
out to be a really really nice blue (I think) glaze, that everyone just
loved. Pots and pots got fired with this glaze, it was a huge amount of
glaze and a big success.
Years later, back in Kansas City Pete went to a crafts fair. At the end of
the day he came across a lone potter, who had one pot glazed with this ver=
y
glaze. Recognizing it, he asked what it was. The potter replied that it was
a sad story: it was the last pot fired with a glaze that some potter had
made up and then left town with the recipe and never gave out the secret.
Sharon
(thanks, guys for all the help w/ clock - my worry was that if I glued
something on the back it would eventually come crashing down off the wall
and break everything in sight. So it's forward, march now.)
Paul Lewing on sat 21 aug 10
On Aug 21, 2010, at 7:20 AM, sharonia628 wrote:
I have seen these glazes labeled as GOK glaze (god only knows), WONDER
glaze
(as, I wonder what's in it) etc.
This is slightly off the original topic, but I remember Louis Katz
once telling us on Clayart that the secret to getting students to use
up that barrel of not-so-wonderful glaze was what you labeled it. He
said the name "Moonlight Over Montana" was the best name he'd found to
get it to disappear fast.
Paul Lewing
www.paullewingtile.com
www.paullewingart.com
Ann Brink on sat 21 aug 10
I keep a 5 gallon bucket of water in my glazing area, for washing glaze off
bowls, utinsels, my hands, etc. After a while the bucket has a lot of
settled glaze on the bottom, so I pour off most of the water into a new
bucket, strain the scrap glaze and give it a name, as in "WB6"
(washbucket6), and so on. After firing some of it on a test piece, I decide
how to improve it..and try several more tests which have copper, cobalt,
and/or opacifier added to it. I have way more glazes in the blue and green
family than I'll ever use, but some have turned out really nice. I know
some of you are banging your fists on your forehead after reading this! I
just really hate to throw things out.
Ann Brink in Lompoc CA
(mostly about pottery)
----- Original Message -----
From: "Paul Lewing"
To:
Sent: Saturday, August 21, 2010 2:20 PM
Subject: Re: scrap glaze
> On Aug 21, 2010, at 7:20 AM, sharonia628 wrote:
>
> I have seen these glazes labeled as GOK glaze (god only knows), WONDER
> glaze
> (as, I wonder what's in it) etc.
>
> This is slightly off the original topic, but I remember Louis Katz
> once telling us on Clayart that the secret to getting students to use
> up that barrel of not-so-wonderful glaze was what you labeled it. He
> said the name "Moonlight Over Montana" was the best name he'd found to
> get it to disappear fast.
>
> Paul Lewing
> www.paullewingtile.com
> www.paullewingart.com
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Louis Katz on sun 22 aug 10
Hear is an old column I wrote for the NCECA Journal years ago. I no longe=
=3D
r
segragate sinks, and I am not nearly as good at reusing glaze scrap as I
once was. I am more dedicated to the idea of having good usable glazes. T=
=3D
he
studio is more fully used and space for scrap glazes is valuble. But here=
=3D
it
is. Please note that the name of the column is not my doing.
Ask the Doctor:
Preventative Medicine
"Waste Not"
Dear Doctor,
I goofed mixing a bucket of a glaze wrong. I apparently switched recipes
mid-stride. Can you help me find a use for this runny green glop.
Sincerely,
Oops in Michigan,
Dear Doctor,
Our glaze area sink does not have a trap, so we have been washing brushes=
=3D
,
buckets and other glazing tools in trash cans filled with water. The seco=
=3D
nd
can is almost filled. I would hate to throw away this material. What shou=
=3D
ld
I do?
Sincerely,
To the Rim in Arizona,
Dear Oops and Rim,
I applaud your desire to conserve resources, protect the environment, sa=
=3D
ve
money and avoid violating the first principle ( never throw anything away=
=3D
).
My first experience with recycled glaze ingredients was when my job was t=
=3D
o
empty a 15 gallon trap built into the floor at the University of Michigan=
=3D
in
1974. This material without any alterations was an acceptable semi matte
black. If I remember correctly we called it Scrap Black. It was not very
popular, It might still be there..=3D20
My next experience was while my wife was teaching at University of Missou=
=3D
ri,
Columbia. We had inherited a good deal of glaze remnants with little
documentation and a five gallon trap full of glaze material. We mixed it =
=3D
all
together and developed a few glazes with these materials. Named "Moonligh=
=3D
t
over Montana" and other colorful names these firing sensitive glazes wit=
=3D
h
complex surfaces were studio favorites until they ran out.
In the Island University studio I segregate the clay washing sink from th=
=3D
e
glaze sink. This limits the variation in the scrap and insures that the
glaze scrap will at least come close to melting. When altering the glaze=
=3D
scrap I try to use only inexpensive ingredients, and only those that are
O.K. to dispose of in landfills. I mix and sieve the scrap and test it in=
=3D
our normal firing cycle. If the scrap has chunks in it that don't want to=
=3D
mix in I throw the chunks away.
Runny glazes that craze get additions of clay, sometimes ball clay,
sometimes kaolin, occasionally a red clay. I use additions of about 2 pou=
=3D
nds
to five gallons. I don't bother weighing it. Glazes that craze but are no=
=3D
t
runny get silica straight up or talc and silica. I use the talc when I am=
=3D
short on matt glazes in the studio. Scrap that doesn't seem quite melted
usually gets whiting or dolomite. If the glaze doesn't get close in the
first two or three alterations I throw it away.
I favor Red Iron Oxide, and Rutile as colorants to add to scrap glazes. F=
=3D
or
five gallons I use about 250 grams (1/4 pound). When the scrap glazes sta=
=3D
rt
to build up however, some cobalt carbonate will increase usage. If the gl=
=3D
aze
is not already too dark cobalt carbonate 100 grams should make a big
difference in five gallons of glaze. With it's cost, it better. I usuall=
=3D
y=3D20
prefer to use the big dollar colorants in tested glazes.=3D20
Kathy Forer on sun 22 aug 10
Don't forget layering!
I've only ever worked with glaze once in a semester's class at a community =
c=3D
enter albeit with the terrific teacher, Brian Quincannon. We were each assi=
g=3D
ned a base glaze and encouraged to pour and dip the seven other glazes.=3D2=
0
Because it didn't seem important to me, I chose last and ended up with a pr=
e=3D
tty ordinary black as base. It made for some wonderful experiments! Almost =
a=3D
hare's fur when under poured white or blue.=3D20
Enjoy!
Kathy Forer
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