John Hesselberth on mon 16 aug 04
Recently I've been intrigued by putting on glaze on top of another and
seeing what happens. By this I mean dipping in one glaze, letting it
dry to the point it can be handled, and then dipping in another glaze.
My first experiment doing this, a couple years ago, was kind of
accidentally spectacular and I have finally had some time to follow up
on it and explore the area a little more.
I find it fascinating that sometimes the underneath glaze will
periodically "break through" the top glaze and show its color in random
and variable size spots or speckles. In other cases you seem to get
more of a "landscape" pattern where the interaction between the two
glazes happens in a very different way. Other times the nature of the
top glaze will completely change based on its interaction with the
bottom glaze.
This technique seems to be another way to get effects from an electric
kiln that are thought to be unique to gas reduction. The more I learn
about my electric kiln and how to work with glazes in it the more
impressed I become with its potential. We potters, collectively, have
been wasting that potential with our "Kiln Sitter" mentality (put a
small cone in the sitter, turn it on high, and come back the next day)
and our reliance on commercial glazes where we don't have a clue about
their composition. My head is bubbling with next experiments to try--so
many experments, so little time.
This afternoon I shot some pictures of some of my recent experiments.
If you are interested in seeing them I have posted them on the
masteringglazes.com web site at:
http://www.masteringglazes.com/Pages/Updateframe.html
Regards,
John
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Ivor and Olive Lewis on tue 17 aug 04
Dear John Hesselberth,
Some years ago I had a long flirtation with this sort of thing but
instead of giving full all over coverage with a second recipe I piped
lines of glaze, parallel to each other, across the ground coat. This
encouraged a variety of interactions where along the edges of the
overlap as well as the "boiling through" effects. Have a look in Greg
Daly's book. He is a great believer in the interactivity of glazes
with markedly differing constituents.
Great play can be had by interspersing "marks" of various forms or
shapes with slip trailers, brushes or stamps.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Diane Palmquist on tue 17 aug 04
John,
I have been doing this for many years and have had some very wonderful
results. Not all glazes work well however. I experimented with a two glazes
to find that only one combination worked. If I put the blue down first I had
LOTS of pin holes. If I put the green down first I have a wonderful new
color. I have been doing this for about a year now and the last kiln firing
the glaze crawled where it overlapped on all pieces. Any thoughts from
anyone out there on why?
thanks,
Diane
----- Original Message -----
From: "John Hesselberth"
To:
Sent: Monday, August 16, 2004 8:10 PM
Subject: Glaze on Glaze Experiments
> Recently I've been intrigued by putting on glaze on top of another and
> seeing what happens. By this I mean dipping in one glaze, letting it
> dry to the point it can be handled, and then dipping in another glaze.
> My first experiment doing this, a couple years ago, was kind of
> accidentally spectacular and I have finally had some time to follow up
> on it and explore the area a little more.
>
> I find it fascinating that sometimes the underneath glaze will
> periodically "break through" the top glaze and show its color in random
> and variable size spots or speckles. In other cases you seem to get
> more of a "landscape" pattern where the interaction between the two
> glazes happens in a very different way. Other times the nature of the
> top glaze will completely change based on its interaction with the
> bottom glaze.
>
> This technique seems to be another way to get effects from an electric
> kiln that are thought to be unique to gas reduction. The more I learn
> about my electric kiln and how to work with glazes in it the more
> impressed I become with its potential. We potters, collectively, have
> been wasting that potential with our "Kiln Sitter" mentality (put a
> small cone in the sitter, turn it on high, and come back the next day)
> and our reliance on commercial glazes where we don't have a clue about
> their composition. My head is bubbling with next experiments to try--so
> many experments, so little time.
>
> This afternoon I shot some pictures of some of my recent experiments.
> If you are interested in seeing them I have posted them on the
> masteringglazes.com web site at:
>
> http://www.masteringglazes.com/Pages/Updateframe.html
>
> Regards,
>
> John
>
>
> John Hesselberth
> http://www.frogpondpottery.com
> http://www.masteringglazes.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.
>
funkfamily on tue 17 aug 04
I've been using splashes of bright sky blue over raspberry, it's beautiful!
And if I overdip blue on raspberry, it gives a beautiful mottled purple,
very nice textured effect.
BTW, John, once in a while I'm getting cracks and crazing with the
raspberry. Any recommendations to avoid this? I'm pretty new at mixing
glazes, and don't have a very good knowledge of the chemistry. The glaze is
so beautiful, that it's worth a few mishaps.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of John
Hesselberth
Sent: Monday, August 16, 2004 8:10 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Glaze on Glaze Experiments
Recently I've been intrigued by putting on glaze on top of another and
seeing what happens. By this I mean dipping in one glaze, letting it dry to
the point it can be handled, and then dipping in another glaze.
My first experiment doing this, a couple years ago, was kind of accidentally
spectacular and I have finally had some time to follow up on it and explore
the area a little more.
I find it fascinating that sometimes the underneath glaze will periodically
"break through" the top glaze and show its color in random and variable size
spots or speckles. In other cases you seem to get more of a "landscape"
pattern where the interaction between the two glazes happens in a very
different way. Other times the nature of the top glaze will completely
change based on its interaction with the bottom glaze.
This technique seems to be another way to get effects from an electric kiln
that are thought to be unique to gas reduction. The more I learn about my
electric kiln and how to work with glazes in it the more impressed I become
with its potential. We potters, collectively, have been wasting that
potential with our "Kiln Sitter" mentality (put a small cone in the sitter,
turn it on high, and come back the next day) and our reliance on commercial
glazes where we don't have a clue about their composition. My head is
bubbling with next experiments to try--so many experments, so little time.
This afternoon I shot some pictures of some of my recent experiments.
If you are interested in seeing them I have posted them on the
masteringglazes.com web site at:
http://www.masteringglazes.com/Pages/Updateframe.html
Regards,
John
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.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.
John Hesselberth on tue 17 aug 04
Hi Diane,
By any chance did you let the first glaze get really dry before
applying the second, whereas you normally wait only a few minutes?
John
On Tuesday, August 17, 2004, at 07:19 AM, Diane Palmquist wrote:
> I have been doing this for about a year now and the last kiln firing
> the glaze crawled where it overlapped on all pieces.
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Diane Palmquist on tue 17 aug 04
John,
No I did it as usual. About 1/2 hour to five minutes between
application. On the bottom of the piece it actually popped off onto the
shelves. I am confused. The green was a bit on the thin side. I would have
thought a thicker application might have made a difference!
Diane
----- Original Message -----
From: "John Hesselberth"
To:
Sent: Tuesday, August 17, 2004 9:05 AM
Subject: Re: Glaze on Glaze Experiments
> Hi Diane,
>
> By any chance did you let the first glaze get really dry before
> applying the second, whereas you normally wait only a few minutes?
>
> John
> On Tuesday, August 17, 2004, at 07:19 AM, Diane Palmquist wrote:
>
> > I have been doing this for about a year now and the last kiln firing
> > the glaze crawled where it overlapped on all pieces.
> John Hesselberth
> http://www.frogpondpottery.com
> http://www.masteringglazes.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.
>
John Hesselberth on tue 17 aug 04
On Tuesday, August 17, 2004, at 09:36 AM, funkfamily wrote:
> BTW, John, once in a while I'm getting cracks and crazing with the
> raspberry. Any recommendations to avoid this?
What kind of clay are you using? I'm guessing porcelain and one that is
at the low end of the scale on coefficient of expansion. I will
reformulate it to reduce the COE of the glaze, but the color may not be
the same. This glaze is quite sensitive to color vs. composition.
I'll send you a reformulation off-list in a day or two and ask you to
let me know the results if you test it.
John
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Jason Hooper on tue 17 aug 04
I've been wonderfully surprised by the surfaces that you get with
layering of glazes. There are several combinations I've settled on for
now, but I continue to test more overlaps with every glaze firing. One
combination uses the MC6G High Calcium Semimatte over Glossy Base 2. You
can see Variegated Slate Blue over Glossy Base 2 Cobalt on my web site,
along with some others -
http://home.swbell.net/jjhooper/
- you can see the fur where the majority of the pot is glaze overlap.
Randy's Red over Bone gives lovely variegation, and the 'woodfired
effect' Nutmeg works well too, in this case over Licorice.
I have found that layering the High Calcium Semimatte over Glossy Base 2
pulls the glaze away from the pot, giving crawling along the junctions
of the glazes. Bisquing on the first layer of glaze is the only cure
I've found so far. The crawling is bound to show up when there are as
many stripes as my pots have ;-)
The Bone and Oatmeal have both given a pink/blue sheen over other glazes
such as Floating Blue and Waterfall Brown, but I haven't figured out
where the color comes from. Haven't got a good photo to hand though.
The order of layering makes a huge difference, so I make test bowls
which are Glaze 1 on one half with stripes of Glaze 2, and Glaze 2 on
the other half with stripes of Glaze 1, like this:
http://home.swbell.net/jjhooper/2004/Glaze%20testers.JPG
Sometimes one glaze just melts into the other without a trace, but the
reverse is dramatic.
cheers,
Jason
John Hesselberth wrote:
> Recently I've been intrigued by putting on glaze on top of another and
> seeing what happens. By this I mean dipping in one glaze, letting it
> dry to the point it can be handled, and then dipping in another glaze.
> My first experiment doing this, a couple years ago, was kind of
> accidentally spectacular and I have finally had some time to follow up
> on it and explore the area a little more.
Paul Lewing on tue 17 aug 04
Hi, John and all.
I've done a lot of this myself. It's not uncommon for a large tile mural of
mine to have dozens of different glazes on it, and they almost all overlap
with something else, so I've seen a lot of this. Here are some things I've
learned:
The more DISSIMILAR the recipes are, the more interaction there will be. If
you overlap two color variations of the same base, you are most likely to
get the top one just covering up the bottom one, with no interaction. The
wildest color shifts come when the two glazes have an entirely different
flux set.
Pay attention to the relative Al:Si ratios. The more DIFFERENT the ratios
are, the runnier the overlap will be. To get a really strong interaction on
a flat surface, I need a difference in ratios of about 7 (e.g. a ratio of
5:1 in one glaze and 12:1 in the other).
Look at Loss on Ignition. If the bottom glaze has a lot of it, it will
bubble up through the top one. While dissimilar recipes and ratios usually
cause a streaky pattern, this usually causes a spotted effect. High calcium
glazes based on whiting (which loses 40% on ignition) are good candidates
for bottom glazes, as several have already noted. Reformulate those whiting
glazes to use wollastonite, and watch that effect go away.
Watch out for glazes with too high a clay content, particularly ball clay.
This is what will cause the crawling, and it doesn't seem to matter which
one is on top. You may have to calcine some of the clay to fix this.
Sometimes, when an overlap crawls when neither glaze alone will, you can fix
it by letting the glaze settle and decanting the water off. Sometimes it
takes several times of doing this to fix it. I have no idea why this should
work, but it sometimes does.
Happy overlapping!
Paul Lewing, Seattle
Alisa Liskin Clausen on wed 18 aug 04
>
>I find it fascinating that sometimes the underneath glaze will
>periodically "break through" the top glaze and show its color in random
>and variable size spots or speckles.
>
>This technique seems to be another way to get effects from an electric
>kiln that are thought to be unique to gas reduction. >
Dear John,
I am especially pleased for you that you are overlapping with glazes. Now
that you and Ron have developed a wonderful group of glazes that behave
well as individuals, it is right on time for you to see how they do in the
company of others.
Where glazes overlap is often the dividing line of where a pot becomes
spectacular. It is the part of the pot that I look at and draw in my
breath as I see the many, many nuances that two glazes can bring forth.
A chemical reaction, glass, the sparkles and streaks, the absolute beauty.
There are overlapping glazes all around and I do not, at all, would say
this has been a tradition or unique to reduction glazes. In fact,
Clayarters such as Marianne Lombardo and others, discovered what greatness
can come forth from the meeting of two glazes, and we have talked about it
and exchanged combinations. Charles Moore has had success with your
Raspberry and Spearmint, I like the Spearmint over the Licorice. Further,
some glazes do not like each other and bubble, etc.
I frequently use glazes containing Rutile as what I call an "over glaze".
The Rutile runs and streaks and in general gives a feathery or cream
effect "shell" effect over the underlaying glaze.
Also, glosses over mats will often reveal the stiffer mat underneath, as
small dots and thin streaks. Recently I tested all of Peter's new versions
of Weathered Bronze and I found them also to be handsome under a gloss. I
mixed them all also with Ball Clay instead of Kaolin, and I prefered them
all with the Ball Clay, with the exception of Seafoam, which was a clearer
green with Kaolin. I also refired them in the bisque and the mat had a
very good surface.
Firing ramps are of course a factor. I do not have a kiln sitter, I
regulate the temp. to the top and again on the way down again with my
controller.
Well, I could go on and on. And we will, overlapping and jumping up and
down.
I will mix MC6G glazes again as 300 batches and will overlap a go go. I
will post the results. Fun stuff. Glad to hear that you are also
fascinated by this.
regards from Alisa in Denmark
I have an apprentice for 2 months so we are both getting the most out of it.
Linda Ferzoco on sat 21 aug 04
I love doing these kinds of experiments. I'm still working in a school
environment and last semester, one of the first things I did was to make
test tiles of combinations of the schools cone 5 and cone 9 glazes. I
couldn't belive that no one else had done that. What wonderful surprises we
saw.
Similarly, at a recent Ron Roy glaze workshop in Sacramento, our group
experimented a little. We may have been overwhelmed with how many tiles we
ended up with, but we developed some wonderful new cone 6 glazes with our
infernal experimenting. Photos have been taken and, I assume, will be
posted, along with recipes.
Cheers,
Linda Ferzoco
Pacifica, California
grateful to be out of the 101 heat of Sacramento and into the fog.
On Mon, 16 Aug 2004 20:10:19 -0400, John Hesselberth
wrote:
>Recently I've been intrigued by putting on glaze on top of another and
>seeing what happens. By this I mean dipping in one glaze, letting it
>dry to the point it can be handled, and then dipping in another glaze.
>My first experiment doing this, a couple years ago, was kind of
>accidentally spectacular and I have finally had some time to follow up
>on it and explore the area a little more.
>
>I find it fascinating that sometimes the underneath glaze will
>periodically "break through" the top glaze and show its color in random
>and variable size spots or speckles.
Carol Ryan-Aube on fri 27 aug 04
John - I made a beautiful bowl with MS6 glazes which I must say was inspired
by Bert Gibson. Birt has pricutes at his site using bone as the base and
various colors on the rims. I first dipped the bowl in bone. Then I dipped
the rim in bright sky blue about 1/2" down. Then I dipped the very top rim
in raw seinna. The bone came out a nice creamy yellow and the rim a mixture
of blue and brown. I hope to try it again in the next load.
Another combination I like is to dip the pot in raw seinna first and then in
bright sky blue - it makes a very pretty dark blue brown color.
Carol Ryan-Aube
Palmer, Alaska - Wonderful summer - over 70 degree temps for over 50 days
BUT the rain has it - Oh well - we need the rain and fall will soon be here.
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