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bailey's gas kiln setting?

updated sat 25 apr 98

 

hasebe on fri 24 apr 98

I have a bailey's studio 28/18 gas kiln (three 12x24 shelves). When I repaired
interior walls, I coated with ITC-100, its firing time was reduced
significantly, though now I need to readjust the setting of the kiln. Top
shelves on a front door side gets too hot, about corn 2 different from the
bottom and corn 1 from the rests. My current setting after body reduction is as
follows:

Natural gas pressure 3.2 (This is my max.)
Damper 3" open
Blower flap 1/2" open with approximately half the blower speed
Target brick is placed 19" from a wall on the chimney side
Approximate firing cycle is 9 hours to cone 10 (Now Top cone 11 is completely
down when bottom cone 9 down)
Ox. probe reading .62-.65

I have been using this setting for a couple of years and top and bottom have
been the same difference. It was all right since it took me for 14 - 15 hours
to fire the kiln then, especially loner hours after cone 8 to 10. Now with
ITC100 coating, a speed of temperature rise is so quick, and the temperature
difference becomes the problem (Opaque glaze on top runs? and leaves ugry bare
spots.)

Now I am confused what to do. Am I opening either a damper or a blower flap
too much or too little, or target brick is not proper?

I appreciate if someone has the same size kiln (three 12x24" shelves) and help
me on this matter.

Hodaka Hasebe
hasebeh@eznet.net
716-264-9698