search  current discussion  categories  glazes - crystalline 

runny glazes crystalline glazes

updated tue 31 dec 96


R Wuetherick on sun 8 dec 96

To those experimenting with crystalline glazes;

In my so far limited experiance. I have found the best, cleanest, safest
way to fire
pots with crystalline glazes is to simply throw a shallow saucer with a
rising from the center. This cylinder will have the exact circumference of
the pot
you wish to fire. I just throw it when I throw the pot a simple mechanical
matter that will take you what 5 minutes longer. Just bisque the two

After glazing your pot apply alumina hydrate to the top of your saucer and
of the pot. After firing a simple 'tap' with a chisel and voila' very
little grinding to do.
With the two rims edges meeting perfectly and with the alimina hydrate you
will minimize those nasty little drops and shards sticking out from the
sides and bottom of you work. I have a couple of impaitent scars and like
to try minimizing grinding as much as possible.

This way you will never ever have to worry about glaze runs. Especially if
you are
using a very very runny crystaline glaze such as Derek Clarksons beautiful
glaze in the latest edition of Hamer. For interest sake to those that are
trying crystalline glazes it is not uncommon (if not common) to see
SiO2->Al2O3 ratios as high as 35:1- thats runny! Number one rule keep the
Al2O3 down way way way down and keep good
firing logs.

Good luck
Rod Wuetherick
in Calgary, AB, Canada