Judy Musicant on tue 16 oct 07
Hello Potters,
I recently glazed a few pieces with Randy's Red (recipe below), a glaze =
I've used for years. I had added a new batch, which I had tested on an =
upright test tile, to the remains of an older batch - something I've =
done many times before. The two bowls in the firing had large raised =
bubbles on the bottom insides, where the glaze ran down and obviously =
pooled. Some of them broke easily I applied pressure. The mugs had =
smaller bubbles on the bottom of the insides. The outside of the pieces =
looked completely normal. The firing was done under the same conditions =
as always and the glaze was applied to the same thickness as usual. The =
pieces in the same firing with other glazes came out fine. I actually =
did not mix up this latest batch of Randy's Red - another individual =
did, and there might have been some silica or EPK from a new bag in it - =
I don't really remember. Any ideas about what might have caused the =
bubbling? Something different about the silica or EPK, or a mistake in =
the mixing? If so, I wonder what that might be? From now on, I will =
obviously test new glaze batches with small bowls. Thanks for any =
thoughts.
Regards,
Judy
PottersGuildNJ.org
Randy's Red
(Cone 6, Oxidation)
=20
Silica 30 =20
EP Kaolin 5 =20
Kona F4 (Soda) Feldspar 20 =20
Talc 14 =20
Gerstley Borate 32 =20
Bone Ash 3 =20
________________________________
=20
Red Iron Oxide 15 =20
Bentonite 1 =20
=20
Gene Arnold on tue 16 oct 07
Sounds as if the glaze was applied to thick. Maybe??
Gene
mudduck@mudduckpottery.net
www.mudduckpottery.net
----- Original Message -----
From: "Judy Musicant"
To:
Sent: Tuesday, October 16, 2007 11:04 AM
Subject: Bubbling Randy's Red
Hello Potters,
I recently glazed a few pieces with Randy's Red (recipe below), a glaze I've
used for years.
Donna Kat on thu 18 oct 07
On Tue, 16 Oct 2007 11:04:34 -0400, Judy Musicant
wrote:
>Hello Potters,
>
>I recently glazed a few pieces with Randy's Red (recipe below), a glaze
I've used for years. I had added a new batch, which I had tested on an
upright test tile, to the remains of an older batch - something I've done
many times before. The two bowls in the firing had large raised bubbles
on the bottom insides, where the glaze ran down and obviously pooled.
Some of them broke easily I applied pressure. The mugs had smaller
bubbles on the bottom of the insides. The outside of the pieces looked
completely normal. The firing was done under the same conditions as
always and the glaze was applied to the same thickness as usual. The
pieces in the same firing with other glazes came out fine. I actually did
not mix up this latest batch of Randy's Red - another individual did, and
there might have been some silica or EPK from a new bag in it - I don't
really remember. Any ideas about what might have caused the bubbling?
Something different about the silica or EPK, or a mistake in the mixing?
If so, I wonder what that might be? From now on, I will obviously test
new glaze batches with small bowls. Thanks for any thoughts.
>
>Regards,
>Judy
>PottersGuildNJ.org
>
>Randy's Red
>(Cone 6, Oxidation)
>
>
>Silica 30
>
>EP Kaolin 5
>
>Kona F4 (Soda) Feldspar 20
>
>Talc 14
>
>Gerstley Borate 32
>
>Bone Ash 3
>
>________________________________
>
>
>
>Red Iron Oxide 15
>
>Bentonite 1
>
>
>
>__________________________________________________________________________
____
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>
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>
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melpots2@visi.com
I recently had some serious blisters with this glaze which had never
happened before - I had just assumed that I had put the glaze on too thick
I also had a rutile glaze on top) but on thinking back I had also added a
small amount of bone ash at someone's recommendation to brighten the color
so I don't know that it wasn't that.
This glaze is about as reliable as it gets. The only real problem with it
that I have found is it being brown from being too thin, cooled too
quickly or having used the wrong iron oxide. Did I just say this is a
reliably glaze????
Donna
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