Vince Pitelka on sat 20 apr 96
Captain Mark -
There is no clear cut answer on whether or not to do an oxidation cleanup. If
all you were concerned with is the reoxidation of the thin parts of a glaze
which breaks colors between thick and thin areas, like a temmoku, then the
oxidation which naturally occurs during initial cooling is usually enough. If
you are concerned about the glaze "healing," that is, if during glaze reduction
you tend to get considerable volatization and resulting bubbling in the glaze,
then a short oxidation soak will allow the glaze to reach equilibrium, and the
bubbles/craters to heal. Whether or not to do an oxidation soak depends
entirely on your experience with your glazes. If regular cooling doesn't give
you the kind of re-oxidation color-breaks you want, it might be a good idea.
If you are getting any pitting, pinholing, or cratering frozen in the glaze
surface it might be a good idea. If you do light reduction and aren't
experiencing either of these conditions it probably doesn't matter.
Some people believe that if you reduce heavily at the end and then shut the
kiln down tight, the reduction atmosphere is somehow locked inside, and this is
of course a falacy. The only way to maintain a reduction atmosphere during
cooling is to do reduction cooling like John Neely does, with the burners on.
Otherwise there is no way to keep some oxygen from entering the kiln, and
surfaces will start to reoxidize almost immediately. At the same time, natural
cooling accelerated by any cold air entering the kiln will rapidly increase the
viscosity of the glazes, slowing down reoxidation and glaze healing. There are
a lot of factors to balance. Only you know best what you want from your own
glazes.
- Vince
Vince Pitelka - wkp0067@tntech.edu
Appalachian Center for Crafts - Tennessee Technological University
Smithville, TN
| |
|
