tmartens on thu 9 jul 98
Out of half a kiln load of mugs (the rest other stuff) one mug had some
strange cracks. Five cracks more or less equidistant, starting at the
lip and going halfway down the mug. All the others were fine, all the
same clay, the same size......anybody have any ideas as to why this
happened?
Toni Martens in a chilly Durban SA, what bliss, long may it last.
Fabienne on fri 10 jul 98
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At 11:49 AM 7/9/98 EDT, you wrote:
=3E----------------------------Original message----------------------------
=3EOut of half a kiln load of mugs (the rest other stuff) one mug had some
=3Estrange cracks. Five cracks more or less equidistant, starting at the
=3Elip and going halfway down the mug. All the others were fine, all the
=3Esame clay, the same size......anybody have any ideas as to why this
=3Ehappened?
=3EToni Martens in a chilly Durban SA, what bliss, long may it last.
According to Hamer=26Hamer's Dictionary (love that book :)), this kind of
crack in biscuit ware is probably caused by latent or dormant cracks that
developed at the raw stage. To avoid them, they prescribe careful drying
and firing which may have been too rapid in the early stages of the biscuit
ware. The other least likely option is that something happened while
packing the kiln.
Thay have a picture of a vertical crack running from the lip about 3/4 of
the way down the side of the wall.
All these buiscuits make me hungry =3B) Hope this helps.
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=B0=60=B0=BA=A4=F8,=B8=B8,=F8=A4=BA=B0=60=B0=BA=A4=F8,=B8=B8,=F8=A4=BA=B0=60
Fabienne =7C Yes, I have learned from my
http://www.vivelafrance.org =7C mistakes...
=7C I can reproduce them exactly.
John K. Dellow on sat 11 jul 98
Fabienne ,if a pot is dried & left a long time & you are in an area with large
fluctuations in humidity, the pot will reabsorb moisture in high humidity and
dry again in low. This can cause the same type of cracks. Some times not
noticeable until after bisqueing. I have also seen such cracks in fine
earthenware seal up in the glaze firing.
John Dellow
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