Frank Gaydos on wed 14 apr 10
We fire at cone 04 on terracotta.=3D20
For the last year some glazes will jump off the pot and land on the kiln sh=
=3D
elf.=3D20
I tried firing slower thinking they may be too wet. I soak for an hour prio=
=3D
r to firing on auto pilot in the computer kiln, at 200F.=3DC2=3DA0Did not s=
eem =3D
to make a difference. The problem mainly happens with layering of two diffe=
=3D
rent glazes. Sometimes the kids apply=3DC2=3DA0them too thick, but mostly a=
n ac=3D
ceptable thickness. It's as if the glaze slides off the clay in SPOTS the s=
=3D
ize of a quarter. The clay is bare where the glaze fell off. Crawling.=3D20
I bisque at cone 05. I also use Epsom salt as a suspender.=3D20
Do you think the salts have anything to do with the problem. Or,=3DC2=3DA0i=
s th=3D
e =3DC2=3DA0bisque too high? Or do you think the glazes are too thick? Firi=
ng t=3D
oo fast?=3D20
I use=3DC2=3DA0the L&L auto quick fire program.=3D20
How about the glazes in the bucket? Should they be a certin specific gravit=
=3D
y?=3D20
I usually eye them and if I see the hairs on my hand then I let it go.=3D20
Any feedback is appreciated.=3D20
Frank=3D20
Ann Brink on wed 14 apr 10
Hello Frank,
Have you changed clays? Have you noticed if the bare clay is smoother and
more dense in areas where the glaze slid off? Just an idea. I would try a
longer soak too. But if your procedure is the same and you are only recentl=
y
having the problem, something must have changed, I would guess.
Ann Brink in Lompoc CA
(mostly about pottery)
----- Original Message -----
From: "Frank Gaydos"
To:
Sent: Tuesday, April 13, 2010 9:51 PM
Subject: Glaze problem- Crawling
We fire at cone 04 on terracotta.
For the last year some glazes will jump off the pot and land on the kiln
shelf.
I tried firing slower thinking they may be too wet. I soak for an hour prio=
r
to firing on auto pilot in the computer kiln, at 200F. Did not seem to make
a difference. The problem mainly happens with layering of two different
glazes. Sometimes the kids apply them too thick, but mostly an acceptable
thickness. It's as if the glaze slides off the clay in SPOTS the size of a
quarter. The clay is bare where the glaze fell off. Crawling.
I bisque at cone 05. I also use Epsom salt as a suspender.
Do you think the salts have anything to do with the problem. Or, is the
bisque too high? Or do you think the glazes are too thick? Firing too fast?
I use the L&L auto quick fire program.
How about the glazes in the bucket? Should they be a certin specific
gravity?
I usually eye them and if I see the hairs on my hand then I let it go.
Any feedback is appreciated.
Frank
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23:31:00
Ron Roy on wed 14 apr 10
Hi Frank,
I have cured the problem by changing the clays in the glazes - do you =3D20
mix your own?
The Epsom is flocculating so it does increase shrinkage - I would =3D20
advocate ball clay instead of Kaolin, then bentonite if there is still =3D2=
0
a settling problem - then Epsom if necessary.
I can change the glazes very easily if you need that done.
RR
Quoting Frank Gaydos :
> We fire at cone 04 on terracotta.
>
> For the last year some glazes will jump off the pot and land on the =3D20
> kiln shelf.
>
> I tried firing slower thinking they may be too wet. I soak for an =3D20
> hour prior to firing on auto pilot in the computer kiln, at =3D20
> 200F.=3DC2=3DA0Did not seem to make a difference. The problem mainly happ=
ens =3D
=3D20
> with layering of two different glazes. Sometimes the kids apply=3DC2=3DA0=
them =3D
=3D20
> too thick, but mostly an acceptable thickness. It's as if the glaze =3D20
> slides off the clay in SPOTS the size of a quarter. The clay is bare =3D2=
0
> where the glaze fell off. Crawling.
>
> I bisque at cone 05. I also use Epsom salt as a suspender.
>
> Do you think the salts have anything to do with the problem. Or,=3DC2=3DA=
0is =3D
=3D20
> the =3DC2=3DA0bisque too high? Or do you think the glazes are too thick? =
=3D20
> Firing too fast?
>
> I use=3DC2=3DA0the L&L auto quick fire program.
>
> How about the glazes in the bucket? Should they be a certin specific grav=
i=3D
ty?
>
> I usually eye them and if I see the hairs on my hand then I let it go.
>
>
>
> Any feedback is appreciated.
>
>
>
> Frank
>
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