Overall's on wed 24 nov 10
Firstly, thank you Vince for your RIO and water only wash for the figurativ=
=3D
e sculpture.
It was a bit tricky trying to figure out the right consistency to stain wit=
=3D
hout saturating the bisque in water and uneven applications.=3DA0 A natural=
b=3D
ristle calligraphy type brush kept the wash stirred and held plenty to appl=
=3D
y the wash.=3DA0=3D20
The perfect tool for brushing off the excess was a plastic haircolor mixing=
=3D
and application brush as its bristles are stiff.=3DA0 These are great for =
le=3D
aving in small buckets of glaze as stir sticks, too.=3DA0 Damp sponges just=
w=3D
iped off everything and re-saturated the bisque where it wouldn't take on c=
=3D
olor.=3DA0=3D20
brush image example:=3DA0 http://www.stylebell.com/ProductDetails.asp?Produ=
ct=3D
Code=3D3DSB-01341&click=3D3D67023
What I would like to learn from clayarters is if I can use an opacifier and=
=3D
water to make a 'white water wash' over bisque?=3DA0 Zircopax, or tin oxid=
e,=3D
or what about talc?=3DA0 Would a matte white glaze be better and brush awa=
y =3D
for effect?
If an opacifier only, will it be better to mix with a bit of Gerstley Borat=
=3D
e or just water?=3DA0 It seems adding only water is much better than adding=
a=3D
nything else.
Happy Thanksgiving Y'all
I'll be firing on Thanksgiving Day and I'm excited!=3DA0=3D20
Turkey, dressing and pumpkin pie will be the menu for Christmas=3DA0 this y=
ea=3D
r.
Kim in Houston
Ann Brink on wed 24 nov 10
Hello Kim,
I like a bit of Gerstley Borate in a wash, because I envision it becoming
sticky before the glaze does, during the firing, so helping to prevent
crawling. That's just how I see it.
Ann Brink in Lompoc Ca
(mostly about pottery)
----- Original Message -----
From: "Overall's"
If an opacifier only, will it be better to mix with a bit of Gerstley Borat=
e
or just water? It seems adding only water is much better than adding
anything else.
Stephani Stephenson on wed 24 nov 10
Hi Kim, just to see if I am reading your question correctly:
are you asking about a whitish opaque wash over a darker clay? one that =
=3D
you
can sponge or brush off? almost like the reverse of an iron wash on ligh=
=3D
ter
clay?
If i am even close and without knowing your clay or firing temp,=3D20
One option would be to try using a slipcasting clay body, either premix=
=3D
ed
and thinned down or dry and mixed with water. if you are firing to a lowe=
=3D
r
temp get a cone 06 slipcast body.. that might work if you are firing to a=
=3D
higher temp as well, as it will flux a little bit and adhere well.
the slipcast bodies seem to be pretty forgiving with regard to shrinkage.=
=3D
i
have used them as the basis for underglaze slips and washes.
If you don't have that on hand try using a white dry clay mixed with
water and add flux if need be.
the problem you might run into if using an opacifier and water is that th=
=3D
e
wash will not flux and will not adhere to the clay after firing, so you'l=
=3D
l
likely have to add some flux to the mix.
you could try using an opacified frit to begin with , such as frit 3124, =
=3D
but
the problem with frits is they don't stay suspended very well, so if you =
=3D
go
that route you'll need to either add some white clay or another suspende=
=3D
r
such as bentonite.
Vince Pitelka on wed 24 nov 10
Kim wrote:
"What I would like to learn from clayarters is if I can use an opacifier =
=3D
and
water to make a 'white water wash' over bisque?=3DA0 Zircopax, or tin =3D
oxide, or
what about talc?=3DA0 Would a matte white glaze be better and brush away =
=3D
for
effect?"
Hi Kim -=3D20
First, I have never used a brush to remove the excess oxide, and cannot
imagine how that would be an improvement over a sponge. The =3D
effectiveness
of the sponge depends on how you use it. Squeeze as much water out of =3D
the
sponge as you can, and lightly skim the surface of the piece. The =3D
amount of
pressure you apply will determine the amount of oxide you remove. You =3D
will
be transferring very little more water to the piece. Most of the water
absorbed by the piece happens when you are applying the oxide wash, but =3D
that
is an irrelevant consideration, because you need to dry the piece off =3D
before
glazing anyway. =3D20
Have a large bucket of water handy, and use a large flat sponge - a good
poly sponge that isn't too soft and flimsy. Wash out the sponge =3D
frequently,
because otherwise you are just re-spreading the oxide that you are =3D
trying to
remove. Be sure to wring out the sponge thoroughly every time. Using =3D
this
method, you can just lightly remove oxide from the high spots, or you =3D
can be
a little more aggressive and remove some from the recesses. =3D20
The most common mistakes in using this method are having the sponge too =3D
wet,
in which case it removes almost all the oxide, or in applying too much
pressure, in which case it removes almost all the oxide. =3D20
Regarding the zircopax wash, I have used this in the past with some =3D
success,
and have also done the same with tin oxide. In general regarding oxide
washes, if you are using them by themselves with no glaze, then you need =
=3D
to
add a little flux like Gerstley borate or 3134 frit (about one part flux =
=3D
to
ten parts oxide, including Zircopax) to fire it onto the surface. This =3D
is
especially true with the Zircopax, because it is extremely refractory, =3D
and
with no flux to hold it in place, and no glaze over it, after the firing =
=3D
you
would just have loose white powder on the surface. =3D20
You wrote:
"If an opacifier only, will it be better to mix with a bit of Gerstley
Borate or just water?=3DA0 It seems adding only water is much better than =
=3D
adding
anything else."
I am confused by your last statement. Adding only water is better only =3D
if
it works. Depending on the temperature you are firing too, some of the
oxides remain very refractory and powdery. If you are using the oxide =3D
under
a glaze and sponging off some of it before applying the glaze, it =3D
usually
works fine without adding anything to the oxide, but if you are using =3D
the
oxide patina with no glaze added, it is usually necessary to add some =3D
flux
like Gerstley borate or 3134 frit.=3D20
The Zircopax wash will give a milky effect where thin, and total opacity
where it retains any thickness at all. I think it would be a good idea =3D
to
always add some flux to a Zircopax wash, because without it you might =3D
have
trouble getting the glaze to adhere (if you are applying a glaze over =3D
the
wash), since it is so refractory. Under a clear glaze it will be white, =
=3D
and
under a colored transparent glaze it will obviously take on that color. =
=3D
If we knew what kind of effect you want, we could give better advice.=3D20
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu=3D20
http://iweb.tntech.edu/wpitelka
Overall's on thu 25 nov 10
link for white wash effect goal at cone ten reduction
http://www.triodisplay.com/catalog/includes/osc_includes/floor_logos/lamina=
=3D
te/White_wash_Oak.jpg
semi-transparent or translucent white, thin, soft visually and to touch
I'd like to try brushing coloring oxides on greenware first, bisque fire, a=
=3D
nd then do a white wash for the exterior glaze.
Thank y'all for the info on adding a flux with opacifiers.
Lou Turner mentioned also he adds a bit of salt which intrigued me a lot,=
=3D
=3D20
but the commercial clay I'm using (Balcones White) and salt don't do well.=
=3D
=3DA0 Balcones in salt fire is like 80 grit sandpaper.
I'd like to try the zircopax and GB with water mixed thin,=3D20
maybe a smidgen bit or porcelain for softness?
HAPPY THANKSGIVING!!!
Kim in Houston with an overcast sky
Snail Scott on thu 25 nov 10
On Nov 24, 2010, at 4:57 AM, Overall's wrote:
> Firstly, thank you Vince for your RIO and water only wash for the
> figurative sculpture...What I would like to learn from clayarters is
> if I can use an opacifier and water to make a 'white water wash'
> over bisque? Zircopax, or tin oxide...
Iron oxide is pretty much the only colorant that
works well without additives as a wash, because
it fuses at normal firing ranges. Most oxides are
more refractory, and zircopax is definitely too
refractory to stick without help. For washes based
on other oxides besides iron, add frit or GB to help
it fuse to the surface during firing. Haven't tried
zircopax myself, but it will certainly need a flux!
I like GB because it not only fluxes but also aids
in suspension.
-Snail
May Luk on thu 25 nov 10
Hello Kim;
I have used kiln wash (half alumina hydrate + half china clay mix with
water to skim milk consistency) as white wash on bone dried greenware.
I then coat it with transparent glaze, fired to cone 8 oxidation. It
is also similar to wash with white velvet underglaze, but more
expensive. I have also tried white glaze wash on bisque without
further glazing, same but slightly different quality in sheen and the
glaze turn the raised part a bit orange. It all depends on how
particular you want your surface.
Another way to try is porcelain slip on buff stoneware clay. (poor
man's porcelain) the buff color clay will show through where the slip
is thin.
Try them all, the pleasure of exploring is all yours.
May
--
http://twitter.com/MayLuk
http://www.ceramicsbrooklyn.com/
| |
|
