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what makes a flaw a flaw? (refiring)

updated sun 15 apr 07

 

David Hendley on sat 14 apr 07


----- Original Message -----
>> In almost every firing I unload a plate or bowl with the
>> tiniest speck of kiln wash in the glaze. It's heartbreaking
>> because it turns a $80 bowl into driveway fill.
>>
> When this sort of thing happens, I smooth the spot with a corner of my
> whetstone, apply more glaze as needed and refire. Just takes a few minutes
> and usually works. I'm curious why you don't do this; have you found
> refiring to not work well, overall?
>
> Ann Brink in Lompoc CA


I sometimes grind out the debris from the glaze, add glaze,
and re-fire pots, but with mixed results.
Some of my glazes, I don't know why, will develop craters
on refiring. I think what is happening is - more of the glaze
moves down the side of the bowl, to the bottom, where it
puddles. It is then too thick, big bubbles form, and a good
whack with a tool will open up a nasty crater - not something
you want to unleash on the handmade pottery market.

Platters are another story. Virtually every platter over 12"
in diameter that I have tried to re-fire is cracked (cooling
crack) after the second firing.

...so, I just generally consider it better to start over, rather
than spend more time and kiln space trying to correct a mistake.

I do get reasonable results refiring, at least on small-to-medium
sized pieces, when I have a failed copper red (no color). I
put a cobalt-rich glaze on top of the failed red and get a passable,
but not exciting, cobalt blue glaze.

David Hendley
Maydelle, Texas
david(at)farmpots(dot)com
http://www.farmpots.com