Layering Opaque Glazes

I am trying to do a test where I put down a layer of black glaze or
underglaze and then put a layer of white on top of it and have it appear as
if the black weren't there at all. This is the most extreme case of a
completely opaque glaze covering something below it. I am doing all my
tests with a Frit Glaze at cone 06.

I have heard that I can simply do this by using 20% or 30% Tin Oxide in my
top glaze, but haven't gotten satisfactory results. I even tried tests with
layers of wax, Krylon spray, and gesso between the two layers in order to
keep them separate. This however led to crazing, I believe because the two
glaze levels were not about to bond with each other sufficiently. I found
some interesting success by mixing the gesso directly with the top coat of
glaze and I have heard of people also doing this with wax resist mixed into
the glaze.

When layers of glaze are applied on top of each other, how much of the
colors bleed together instantly versus when the glass formers are soft in
the firing process? If some of the glaze layers are mixed into each other
during application, does airbrushing on glaze reduce this at all? I would
love to achieve my goal without having to intruduce a third firing stage
between my bisque fire and final fire.

Am I barking up the wrong tree here? Any suggestions, comments.


c ya

John Rigler

John Rigler wrote:
I am trying to do a test where I put down a layer of black glaze or
underglaze and then put a layer of white on top of it and have it appear as
if the black weren't there at all. This is the most extreme case of a
completely opaque glaze covering something below it. I am doing all my
tests with a Frit Glaze at cone 06.

I have heard that I can simply do this by using 20% or 30% Tin Oxide in my
top glaze, but haven't gotten satisfactory results. I even tried tests with
layers of wax, Krylon spray, and gesso between the two layers in order to
keep them separate. This however led to crazing, I believe because the two
glaze levels were not about to bond with each other sufficiently. I found
some interesting success by mixing the gesso directly with the top coat of
glaze and I have heard of people also doing this with wax resist mixed into
the glaze.

When layers of glaze are applied on top of each other, how much of the
colors bleed together instantly versus when the glass formers are soft in
the firing process? If some of the glaze layers are mixed into each other
during application, does airbrushing on glaze reduce this at all? I would
love to achieve my goal without having to intruduce a third firing stage
between my bisque fire and final fire.

Am I barking up the wrong tree here? Any suggestions, comments.


c ya

John Rigler




Trouble is that glazes ain't paints... they depend on the fact that they
melt into a semi liquid state (some is runnier than others) when they
mature... Think of runny honey... If you've got two layers of glaze
they will mix (as part of convection (physics 101))and you will get an
effect that is a mixture of the two (often they don't mix but end up on
the surface sort of wrapped round each other (speckledy, leopard skin
effects) Other times you will get an effect that is a complete
surprise, i.e where one glaze is supposed to be blue, and the other is
supposed to be yellow and the reult is a beautiful lustrous red,,, (only
had it happen once, but it was amazing...)... Sounds like what you need
to look into would be latex resist, where you can apply a glaze onto the
surface and then peel off the latex and apply another glaze.. Tho
they'll still do things as they interface....
They shouldn't mix too badly before the firing if you apply them before
the bottom glaze is completely dry...
Hope this is useful...
Maybe someone else might know more...
Hugs
Eddie

"John Rigler" wrote in message
news:Ow%kf.2117$xg1.1279@trnddc03...
I am trying to do a test where I put down a layer of black glaze or
underglaze and then put a layer of white on top of it and have it appear as
if the black weren't there at all. This is the most extreme case of a
completely opaque glaze covering something below it. I am doing all my
tests with a Frit Glaze at cone 06.

I have heard that I can simply do this by using 20% or 30% Tin Oxide in my
top glaze, but haven't gotten satisfactory results. I even tried tests
with layers of wax, Krylon spray, and gesso between the two layers in
order to keep them separate. This however led to crazing, I believe
because the two glaze levels were not about to bond with each other
sufficiently. I found some interesting success by mixing the gesso
directly with the top coat of glaze and I have heard of people also doing
this with wax resist mixed into the glaze.

When layers of glaze are applied on top of each other, how much of the
colors bleed together instantly versus when the glass formers are soft in
the firing process? If some of the glaze layers are mixed into each other
during application, does airbrushing on glaze reduce this at all? I would
love to achieve my goal without having to intruduce a third firing stage
between my bisque fire and final fire.

Am I barking up the wrong tree here? Any suggestions, comments.


c ya

John Rigler




Like Eddie, I think using latex resist might be the best answer to your
problem. It is cheap and easy to use. Let us know how you go )
A

That reminds me--I just had an odd layering result. I dipped a pot in
burgundy opulence--commercial flat glossy red, and then in cream
breaking red--opaque off-white glaze with gerstley borate that breaks on
edges. The result was red with small white speckles when the cream
breaking red was lighter and extensive crawling of the cream breaking
red over the red when it was heavier. I've never seen a glaze crawl on
top of another glaze like this before.

Janet

Well if you are trying to get crawling, just start applying stuff like Gesso
or Krylon spray between your glaze layers and you will definately get some.
I have played around with some commercial red glazes that seemed to turn
grey at the edges sometimes.

"Janet Price" wrote in message
...
That reminds me--I just had an odd layering result. I dipped a pot in
burgundy opulence--commercial flat glossy red, and then in cream breaking
red--opaque off-white glaze with gerstley borate that breaks on edges.
The result was red with small white speckles when the cream breaking red
was lighter and extensive crawling of the cream breaking red over the red
when it was heavier. I've never seen a glaze crawl on top of another
glaze like this before.

Janet

This is absolutely fascinating about the science of glazes. Please
don't think this a stupid question but why would you want to put a black
under the white? Is there a reason for working so hard to achieve this
technique? Is the end result a raised effect?

~Kroozr

I have been following this thread and still am at a loss as to what you are
trying to accomplish. If for example you would want half a plate black and
half white you would simply dip half in the black, let it dry to touch and
dip the unglazed half in white. If you want overlap with the black showing
through in some form of decoration, you would dip part in the black, let it
dry, use wax resist on the black glaze where you what the black to come
through as black and when that has dried, dip in white with the white
overlapping where the design is. You can carefully wipe off with a damp rag
any white glaze left on the wax resist. Where you overlap though you are
not going to get white or black. You may get blue or green - it depends on
what oxides are in the black.

Do NOT get wax resist in your glazes! Make sure it is dry before putting
the piece back into the glaze.

"John Rigler" wrote in message
news:Ow%kf.2117$xg1.1279@trnddc03...
I am trying to do a test where I put down a layer of black glaze or
underglaze and then put a layer of white on top of it and have it appear as
if the black weren't there at all. This is the most extreme case of a
completely opaque glaze covering something below it. I am doing all my
tests with a Frit Glaze at cone 06.

I have heard that I can simply do this by using 20% or 30% Tin Oxide in my
top glaze, but haven't gotten satisfactory results. I even tried tests
with layers of wax, Krylon spray, and gesso between the two layers in
order to keep them separate. This however led to crazing, I believe
because the two glaze levels were not about to bond with each other
sufficiently. I found some interesting success by mixing the gesso
directly with the top coat of glaze and I have heard of people also doing
this with wax resist mixed into the glaze.

When layers of glaze are applied on top of each other, how much of the
colors bleed together instantly versus when the glass formers are soft in
the firing process? If some of the glaze layers are mixed into each other
during application, does airbrushing on glaze reduce this at all? I would
love to achieve my goal without having to intruduce a third firing stage
between my bisque fire and final fire.

Am I barking up the wrong tree here? Any suggestions, comments.


c ya

John Rigler

In article , the
''Kroozr'' writes
This is absolutely fascinating about the science of glazes. Please
don't think this a stupid question but why would you want to put a black
under the white? Is there a reason for working so hard to achieve this
technique? Is the end result a raised effect?

~Kroozr

When I do that with 2 stoneware glazes I've got the result is akin to
streaks, bubbles, and blobs of cream on a cup of coffee.
--
Steve Mills
Bath
UK

"Steve Mills" wrote in message
...
In article , the
''Kroozr'' writes
This is absolutely fascinating about the science of glazes. Please
don't think this a stupid question but why would you want to put a black
under the white? Is there a reason for working so hard to achieve this
technique? Is the end result a raised effect?

~Kroozr

When I do that with 2 stoneware glazes I've got the result is akin to
streaks, bubbles, and blobs of cream on a cup of coffee.
--
Steve Mills
Bath
UK


My favorite effects come layering one glaze (or even more) over one another.
I have overlapped glazes of every type of firing I can think of (cone 04 to
cone 10 / oxidation and reduction). You can make this look very geometric
in design with dipping or fluid by pouring. A very easy way of making an
interesting look is to dip a fraction of the pot in one glaze, do the next
fraction in an other, and continue until you have covered the entire pot. I
would not do more than 4 glazes since the overlap will give a different
color than the single glaze and it can look too busy (two glazes can
actually give you 4 colors since glaze A on top of glaze B is different than
glaze B on top of glaze A). Plates look really nice with one half done in
one glaze and then 2/3rds done in another. This give three bands of color.
Then take a third glaze or an oxide mixed in one of the glazes and drip it
casually down the middle, over one of the single layers of glaze or over the
all three. How much you overlap will add to the effect as well. You need
to be careful with this because the overlapping glazes can easily be much
more fluid than the single glaze and you don't want the glaze running onto
your shelves. If you haven't done this before, I would recommend doing this
by pouring the glaze rather than dipping and only doing it on the inside of
a plate or bowl. Keep the outside unglazed or just a single glaze. Glaze
also runs easily off the lip so don't let the glaze build up heavily there.

I have never had problems with this technique. I know one potter who insist
on letting the first glaze dry completely (waiting until the next day to do
the second layer). His glazing is some of the best I have seen. I don't
have that kind of patience. The glaze gods are generally kind to me.

Donna

I am interested in the different effects that other people talk about, but
mostly I am attempting to completely cover over a dark color with a lighter
one in order to create a simple image. You can see what I am talking about
at my website:

http://studiotile.com

So I am simply trying to have a background color, often blue rather than
black, and a lighter color in the foreground.

"the ''Kroozr''" wrote in message
...
This is absolutely fascinating about the science of glazes. Please
don't think this a stupid question but why would you want to put a black
under the white? Is there a reason for working so hard to achieve this
technique? Is the end result a raised effect?

~Kroozr