May Luk on mon 21 feb 11
Hello all;
My studio can get very cold as I don't go in often to keep the heat
going. A few glaze buckets have been sitting around for about 4
months. I recently started testing again before I bulk dip for an
order. I found these clear crystal pieces floating in the glaze slope.
The studio was so cold I thought it was ice. Since I weigh out the
glaze density and I thought it didn't matter and I would fire a test
and see what happened.
Yesterday, the studio was quite warm (60 deg F) as I left the heater
on over-night by mistake. Then I realized those crystals are not ice,
as they would have melted by now.
Here's a pict:
http://www.flickr.com/photos/yamerica/5462271267/
The ingredients for the glaze: Custer Feldspar / Frit 3134 /
Wallastonite/ Zinc oxide / Lithium (less than 4 percent) / Silica /
Grolleg / Rutiles / Tin / Bentonite / Veegum
Can I melt the crystal back into the glaze and how so?
Thanks
May
Brooklyn NY
--
http://twitter.com/MayLuk
http://www.takemehomeware.com/
Paul Herman on mon 21 feb 11
Hi May,
This happens to some clayartors every winter. I think it's a condition
from using soluble materials like lithium carbonate and the frit 3134.
These materials dissolve to some extent, and when it gets cold enough
they form the little crystals, or in your case, big crystals.
What you could do is to sieve out all the crystals, dry them and crush
them in a mortar, and add the material back to the warmed glaze slop.
Also, you might be able to dissolve the material by putting it in a
saucepan with some water and heating it close to boiling on the stove,
then adding back to the glaze slop.
In my case, when I got the radiant floor heat working in my shop, the
problem went away. They only seem to form if it gets down to about 40F
or less. I confess to being lazy and just throwing the crystals away a
couple of times. I know it changed the glaze composition some, but you
couldn't tell from the fired result. It was a clear ^10 glaze with a
wide firing range, and contained 2% lithium carbonate, and 7% gerstley
borate.
good glazing,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Feb 21, 2011, at 5:30 AM, May Luk wrote:
> Yesterday, the studio was quite warm (60 deg F) as I left the heater
> on over-night by mistake. Then I realized those crystals are not ice,
> as they would have melted by now.
> Here's a pict:
> http://www.flickr.com/photos/yamerica/5462271267/
>
> The ingredients for the glaze: Custer Feldspar / Frit 3134 /
> Wallastonite/ Zinc oxide / Lithium (less than 4 percent) / Silica /
> Grolleg / Rutiles / Tin / Bentonite / Veegum
>
> Can I melt the crystal back into the glaze and how so?
>
> Thanks
>
> May
> Brooklyn NY
Lee on mon 21 feb 11
On Mon, Feb 21, 2011 at 7:30 AM, May Luk wrote:
> Can I melt the crystal back into the glaze and how so?
May, I have put soda ash back into solution by putting the soild
parts in a pan with water skimmed off the top and heating it up.
Do you have a hand blender? It might speed the melt up.
--=3D20
--
=3DA0Lee Love in Minneapolis
http://mingeisota.blogspot.com/
=3DA0"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D9=
7that is, =3D
"The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Hank Murrow on mon 21 feb 11
On Feb 21, 2011, at 5:30 AM, May Luk wrote:
> Hello all;
>=3D20
> My studio can get very cold as I don't go in often to keep the heat
> going. A few glaze buckets have been sitting around for about 4
> months. I recently started testing again before I bulk dip for an
> order. I found these clear crystal pieces floating in the glaze slope.
> The studio was so cold I thought it was ice. Since I weigh out the
> glaze density and I thought it didn't matter and I would fire a test
> and see what happened.
>=3D20
> Yesterday, the studio was quite warm (60 deg F) as I left the heater
> on over-night by mistake. Then I realized those crystals are not ice,
> as they would have melted by now.
> Here's a pict:
> http://www.flickr.com/photos/yamerica/5462271267/
>=3D20
> The ingredients for the glaze: Custer Feldspar / Frit 3134 /
> Wallastonite/ Zinc oxide / Lithium (less than 4 percent) / Silica /
> Grolleg / Rutiles / Tin / Bentonite / Veegum
>=3D20
> Can I melt the crystal back into the glaze and how so?
Could be the Wollastonite, but whatever it is, the remedy is the same. =3D
Strain out all the crystal bits, put them in a small pan on the stove =3D
and dissolve them into the water. Then stir the water into the glaze. =3D
Adjust the glaze for thickness per normal.
Cheers, Hank
John Britt on mon 21 feb 11
May,
Her you go:
http://johnbrittpottery.com/writings/articles/flambe-magic/
www.johnbrittpottery.com
Steve Slatin on mon 21 feb 11
May -- I get this in my lithium-rich glazes also.
The resolution is simpler than you'd think -- I
sieve to remove the crystals and let it settle.
When the clear watery layer has separated, I
take off a few cups of it, and put it in a pot
on a hot plate. I get it up to near boiling,
turn off the heat, and toss the crystals in.
They enter the solution almost immediately,
and I mix that with the thicker slop remaining
in the bucket and re-seive. Not only is it
ready to use now, but it's comfortably warmed.
I tried doing it by just adding hot water and
that does work, but by the time I had all the
crystals suspended, there was quite a bit of
water added, and I had to wait a week with the
lid off the bucket to get back to usable
glaze thickness.
Best wishes --
Steve Slatin
N48.0886450
W123.1420482
--- On Mon, 2/21/11, May Luk wrote:
> Hello all;
>
> My studio can get very cold as I don't go in often to keep
> the heat
> going. A few glaze buckets have been sitting around for
> about 4
> months. I recently started testing again before I bulk dip
> for an
> order. I found these clear crystal pieces floating in the
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