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marvin flowerman's request for info about cone6/7 gas

updated fri 10 dec 04


Kathy McDonald on wed 8 dec 04

firing..experiences and a question


Now that major production of cone 10
work for craft sales is over I plan to do some work
at c6/7 in gas with glazes from John H and Ron Roy's
book. They are all mixed and ready to go.
Now I just need to refuel, regroup, and get some cone 6 clay.

I will keep you and the list posted as my journey progresses.
I am also going to try to get some stains and work with those
in a kind of modified majolica technique.

I've always done my cone 6 work in my electric kilns after
i had a major disaster a few years ago.

Committed a whole load (20 cu. ft of pots) to a cone 6
firing in the gas kiln
and ended up having the entire load literally crack apart
after it had been unloaded for about 24 hours.
The work looked great when it was unloaded glazes were really nice
and soft,
It is difficult to describe what happened to these pieces
but they developed cracks that spiralled all of the way from
the bottom to the top of each pot. I had used several clays
and different glazes so I have no idea why this happened.
I suspect cooling and some type of thermal shock, so when I
venture into this again I will be firing down my kiln and making
sure I cool it very very slowly.


-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of
Sent: Tuesday, November 09, 2004 10:56 AM

on 10/29/04 I asked for anyone on Clayart to "share with me your experience
firing cone 7 reduction in a gas kiln"
No answers yet; would still like to hear from any of you on this subject.


Marvin Flowerman

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Marvpots@AOL.COM on wed 8 dec 04


Kathy, thanks for your comments on cone 6/7 gas firing; I'm using a clay
body that I have used successfully several times before at cone 7 in oxidation.
I'm firing the gas kiln today and hopefully, sometime late tomorrow, may be
able to view the results.


Marvpots@AOL.COM on thu 9 dec 04


The clay body I used did not work well uniformly in reduction at cone 7; my
old cone7 oxidation glazes generally did not work well either.
Nevertheless, I consider the experiment useful, I was able to get very
uniform heat distribution in my kiln and I have concluded that this clay body should
be confined to raku work; I was tryng to get away from the white unglazed
portions (feet, rims,etc.) at cone 7 oxidation in my electric kiln but have now
concluded that I simply need another (darker) clay body for that kind of
oxidation firing.