May Luk on wed 30 sep 09
Hello all;
I am going to try raw glazing on a new tile project. I have a couple of
glazes I am testing. They all have at least 5% of clay and 2 % bentonites.
I will try a CONE 6-7 firing ramp as such:-
38 deg C per hour > 108 deg C (100 F > 226 F)
108 deg C per hour > 550 deg C (226 F>1022F )
68 deg C per hour > 668 deg C (154 F > 1234 F)
108 deg C per hour > 1008 deg C > Hold 8 min (226 F > 1846 F)
128 deg C per hour > 1208 deg C > Hold 8 min (262 F > 2206 F)
I will have a very slow start on the ramp before boiling point, hold 8 min
at the normal top bisque temp and that is my plan.
I have been weighing out the density of my glaze before glazing. (250
gm glaze wt / 250 gm water) I have the density about 1.4. Should the glaze
be thinner or thicker because the greenware is less porous than bisqued
ones?
Many thanks!
May
Brooklyn
--
http://twitter.com/MayLuk
http://www.flickr.com/groups/handmade_mugs/
Lee Love on wed 30 sep 09
On Wed, Sep 30, 2009 at 10:05 AM, May Luk wrote:
> I have been weighing out the density of my glaze before glazing. (250
> gm glaze wt / 250 gm water) I have the density about 1.4. Should the glaz=
e
> be thinner or thicker because the greenware is less porous than bisqued
> ones?
May, can you "test glaze" some tiles? The only true way to know the
thickness of the glaze is by scratching it and eyeballing the
thickness. How thick it should be all depends upon the particular
glaze.
Most of my single fire glazes have more than 15% clay in them.
--
--
Lee Love, Minneapolis
"The tea ceremony bowl is the ceramic equivalent of a sonnet: a
small-scale, seemingly constricted form that challenges the artist to
go beyond mere technical virtuosity and find an approach that both
satisfies and transcends the conventions." -- Rob Sliberman
full essay: http://togeika.multiply.com/journal/item/273/
Clyde Tullis on thu 1 oct 09
It's always important to remember that you are doing bisque first and the=
=3D
n
glaze firing in one firing. So take your time and error on the side of
caution. Your tiles must be allowed to dry fully before firing them. And
when you fire you have to allow for the carbon to burn out of the clay or=
=3D
you will pinhole the glaze. With once-fire, haste makes waste.
How thick are they?
May Luk on thu 1 oct 09
Aiya! My tile is 0.5" thick. They were not completely dried and I knew it.
It's 200 deg C coming down right now... fingers crossed. But I need my firs=
t
sample done before October first. I will find out and post the result here.
http://www.flickr.com/photos/yamerica/3970426894/
I have a feeling the glaze is a bit thin for this trial. Have ordered Veegu=
m
for my next trial.
However this is slower than my usual bisque firing. So..we shall see.
Many thanks!
May
Brooklyn NY
On Thu, Oct 1, 2009 at 4:17 PM, Clyde Tullis wrote:
> It's always important to remember that you are doing bisque first and the=
n
> glaze firing in one firing. So take your time and error on the side of
> caution. Your tiles must be allowed to dry fully before firing them. And
> when you fire you have to allow for the carbon to burn out of the clay or
> you will pinhole the glaze. With once-fire, haste makes waste.
>
> How thick are they?
>
--
http://twitter.com/MayLuk
http://www.flickr.com/groups/handmade_mugs/
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