tony clennell on sat 15 nov 08
When I read of the bust exploding it first sounded like a fast firing.
4 hours of preheat is nothing for a thick piece. Overnight under 200F
or below steam is better and with thick pieces I candle for a day. the
large hand built pieces that I am currently making take two guys to
lift with lots of grunts and the rim is probably 4 inches thick. When
I started talking about these pieces John Neely suggested I include
30% silica sand (10 -50 mesh and 20% 25 mesh coarse). I just screwed
up the courage to fire 2 of the pieces this last week. I made these
two pieces in Sept and they have been sitting in a heated room since.
After an evenings preheat I could still feel steam coming out the flu
so I candled for another day. They came out just fine. they are the
biggest things I've ever made and I was worried.
I place sand under them on the kiln shelf to allow them to shrink.
Oh yeah and during the making after they were complete I covered them
in newspaper and then in plastic and let them sit for a couple of
weeks. I think this helped even out the drying.
Particle size is sooooooo important.
What was that story of the teacher that took a glass and filled it
with small stones and said to the class is the glass full? they
answered yes. he then poured sand into the glass and it found its way
thru the small stones. he then asked if the glass was full and they
all answered yes it is full now!!! He then took some of his coffee and
poured it into the glass and it found it's way between the particles.
The punch line is there is always room for coffee with friends but I
think it illustrates how water can find it's way thru varying particle
sizes. Try filling a cup of with sand and see how it takes a long long
time to reach the bottom.
Clay body for large scale work is paramount.
Just to take it a little further I just added walnut shells, broken
bits of soft brick and feldspar chunks. Now that's an open body!
Best of luck with the thick ware.
Cheers,
Tony
Victoria E. Hamilton on sat 15 nov 08
Great to hear from you Tony!
Do you have photos of these pieces on your blog yet? We'd love to see them.
Take care.
Vicki Hamilton
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of tony clennell
Sent: Saturday, November 15, 2008 8:33 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: My perfect body
When I read of the bust exploding it first sounded like a fast firing.
4 hours of preheat is nothing for a thick piece. Overnight under 200F or
below steam is better and with thick pieces I candle for a day. the large
hand built pieces that I am currently making take two guys to lift with lots
of grunts and the rim is probably 4 inches thick. When I started talking
about these pieces John Neely suggested I include 30% silica sand (10 -50
mesh and 20% 25 mesh coarse). I just screwed up the courage to fire 2 of the
pieces this last week. I made these two pieces in Sept and they have been
sitting in a heated room since.
After an evenings preheat I could still feel steam coming out the flu so I
candled for another day. They came out just fine. they are the biggest
things I've ever made and I was worried.
I place sand under them on the kiln shelf to allow them to shrink.
Oh yeah and during the making after they were complete I covered them in
newspaper and then in plastic and let them sit for a couple of weeks. I
think this helped even out the drying.
Particle size is sooooooo important.
What was that story of the teacher that took a glass and filled it with
small stones and said to the class is the glass full? they answered yes. he
then poured sand into the glass and it found its way thru the small stones.
he then asked if the glass was full and they all answered yes it is full
now!!! He then took some of his coffee and poured it into the glass and it
found it's way between the particles.
The punch line is there is always room for coffee with friends but I think
it illustrates how water can find it's way thru varying particle sizes. Try
filling a cup of with sand and see how it takes a long long time to reach
the bottom.
Clay body for large scale work is paramount.
Just to take it a little further I just added walnut shells, broken bits of
soft brick and feldspar chunks. Now that's an open body!
Best of luck with the thick ware.
Cheers,
Tony
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