Lis Memoli on wed 19 nov 03
So what was it, to preheat the kiln for firing sculpture 1 hour for every
inch thickness of the sculpture? If so, is that just for the bisque firing and
the last firing is how?? What about grog? At what thickness and size of the
piece is grog recommended? Its been too many years. Thanks, Lis Memoli
Snail Scott on fri 21 nov 03
At 07:57 PM 11/19/03 EST, you wrote:
>So what was it, to preheat the kiln for firing sculpture 1 hour for every
>inch thickness of the sculpture? If so, is that just for the bisque
firing and
>the last firing is how?? What about grog? At what thickness and size of the
>piece is grog recommended?
You're talking about candling time? I've never
thought about it in terms of a rule of thumb
before, but I'd say I allow maybe an hour per
1/4" of thickness. A little more for very
tight bodies, and less for very open ones.
That's for the initial firing. Re-firing of
bisque (for glaze or whatever), I'd do about
a half-hour of candling only.
An exception:
if your bisque firing involves a full coverage
coat of underglaze and after bisque it is
glazed, allow much more time to candle. The
moisture from the glaze will penetrate into
the clay, but underglaze is vitrified enough
to not let it escape easily. Let pieces like
this sit and dry a while, and candle longer.
I once saw work blown apart by this effect.
I'd use grog based on the handling properties
of the clay and its suitability for your work.
If it needs to be sturdier and stand up better,
use grog. If you like the way it handles without
grog, skip it. It will stand up in firing better
with grog, but you'll have a sense of its
floppiness while building. If it feels right to
build with, go for it. Personally, I'd hate to
build anything over about 8" tall without grog,
but some forms will accomodate it better than
others.
-Snail
Its been too many years. Thanks, Lis Memoli
>
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Karin Hurt on sat 22 nov 03
We just finished a torso in class, it was put in the reduction kiln in a
near wet stage, candled with a partially open door for 3 days and nights and
then fired as normal, all turned out fine. I'd love to share a picture and
get comments, email me privately and I'll send it, since I don't think I can
include it here in Clayart or use an attachment.
Karin
Lake Havasu City, Arizona
http://www.laughingbearpottery.com
----- Original Message -----
From: Snail Scott
To:
Sent: Friday, November 21, 2003 10:08 AM
Subject: Re: sculpture 'rule of thumb'
> At 07:57 PM 11/19/03 EST, you wrote:
> >So what was it, to preheat the kiln for firing sculpture 1 hour for every
> >inch thickness of the sculpture? If so, is that just for the bisque
> firing and
> >the last firing is how?? What about grog? At what thickness and size of
the
> >piece is grog recommended?
>
>
>
> You're talking about candling time? I've never
> thought about it in terms of a rule of thumb
> before, but I'd say I allow maybe an hour per
> 1/4" of thickness. A little more for very
> tight bodies, and less for very open ones.
> That's for the initial firing. Re-firing of
> bisque (for glaze or whatever), I'd do about
> a half-hour of candling only.
>
> An exception:
> if your bisque firing involves a full coverage
> coat of underglaze and after bisque it is
> glazed, allow much more time to candle. The
> moisture from the glaze will penetrate into
> the clay, but underglaze is vitrified enough
> to not let it escape easily. Let pieces like
> this sit and dry a while, and candle longer.
> I once saw work blown apart by this effect.
>
> I'd use grog based on the handling properties
> of the clay and its suitability for your work.
> If it needs to be sturdier and stand up better,
> use grog. If you like the way it handles without
> grog, skip it. It will stand up in firing better
> with grog, but you'll have a sense of its
> floppiness while building. If it feels right to
> build with, go for it. Personally, I'd hate to
> build anything over about 8" tall without grog,
> but some forms will accomodate it better than
> others.
>
> -Snail
>
>
>
>
> Its been too many years. Thanks, Lis Memoli
> >
>
>___________________________________________________________________________
> ___
> >Send postings to clayart@lsv.ceramics.org
> >
> >You may look at the archives for the list or change your subscription
> >settings from http://www.ceramics.org/clayart/
> >
> >Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
> >
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
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