tgschs10 on sat 5 aug 00
I have both a gas and electric kiln; I have always used the electric =
strictly for bisque. The other day I was working on the gas kiln and =
decided to fire the electric to cone 10 for the first time; no dumb me I =
didn't put any cones around and instead trusted the sensor. I feel that =
I came close to temperature because some of the glazes turned out but =
several had some pinholes. I've recently read something about second =
firings [can't find it at present] and I believe that I have seen some =
comments that second firings can be lower. Is this true? Second, what =
happens when a glaze is second fired say to a lower temperature? Thanks
Tom Sawyer
tgschs10@msn.com
elizabet on sat 5 aug 00
Tom said:
>I've recently read something about second
firings [can't find it at present] and I believe that I have seen some
comments that second firings can be lower. Is this true? Second, what
happens when a glaze is second fired say to a lower temperature? <
There's an article in the Summer 2000, Pottery Making Illustrated,
written by Lili Krakowski called "Twice-Fired Glazes".
She included recipes and pictures of some of her pots that she's
twice fired. Her pots were fired to cone 6 first and then fired again to cone 04.
She said that the ones she has refired to cone 04 are more vibrant and
rich colored than the ones she has only fired once. And she recommends
testing. I have found that whether I refire at cone 04 or decide to go to
cone 5, the results aren't predictable, at least for me yet. I figure if they
aren't absolutely fantastic after the first firing, what have I got to lose, if they
don't improve? Some have been great.
Elizabeth
Nanci Bishof on sun 6 aug 00
I've always taken the electric kiln a cone higher to heal pinholes. The small
firing cones are actually delivering a bit lower temp than their rating. So,
if I want a true 04 temp I fire with an 03 small cone tripping the switch. As
to what happens to the glazes, I get variation within the color when firing a
second lower cone firing. Lana Wilson uses that technique to get some
stunning glaze variation. You can also apply other lower temp rated glazes to
develop the piece, such as lusters.
nanci
Ron Roy on mon 7 aug 00
Hi Tom,
Electric kilns tend to cool faster than gas kilns - simply more mass to
stay hotter longer and gives glazes a better chance to smooth out.
I think a refire to the same cone would smooth em out. It's very helpful to
have a soak at the end of the firing - watch the cone go down - evens the
kiln out and gives the glazes a chance to settle down. When the sitter
trips - turn the kiln back on and watch your guard cone go dowm - very
helpful even if it's only for 15 min. If you are using a controller it's a
piece of cake. Find out what ramp you need to get your cone to just start
and soak till the cone drops to where you want it.
RR.
>I have both a gas and electric kiln; I have always used the electric
>strictly for bisque. The other day I was working on the gas kiln and
>decided to fire the electric to cone 10 for the first time; no dumb me I
>didn't put any cones around and instead trusted the sensor. I feel that I
>came close to temperature because some of the glazes turned out but
>several had some pinholes. I've recently read something about second
>firings [can't find it at present] and I believe that I have seen some
>comments that second firings can be lower. Is this true? Second, what
>happens when a glaze is second fired say to a lower temperature? Thanks
>Tom Sawyer
>tgschs10@msn.com
>
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Ron Roy
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