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once firing to ^05

updated sat 1 may 99


Jeff Lawrence on mon 17 may 99 writes:
> If I want to experiment with one or two pieces for
> single firing, cone 05, should I put them in a bisque
> load or glaze load?

Hi Berry,
Here are two gotchas that got me:

1. I tried once-firing my slipcast ware (electric fired to ^04) and had the
problem that the ware seemed to melt more than the same glaze on a bisqued
piece. I usually bisque in one attitude and glaze fire in another, and I
cast very thin -- might have something to do with it. But I gave up on
once-firing because even when things didn't collapse, they still slumped
into unacceptability. Thicker pieces or of different design might work fine
-- the glaze surface looked fine.

2. When I put a glazed piece into a bisque firing, the glaze always looks
funky and wrinkled. I've only found a single sentence in Parmalee that
describes this defect. Apparently the fumes given off by the raw clay
contain some sulphur compounds which can produce this effect.

Ron Roy gave me some glaze recipes for ^04 which I'm testing on an
embarassingly slow pace. I'll post those when I've got some results to share.

Good luck,
Jeff Lawrence
Sun Dagger Design
Rt. 1 Box 394L
Espanola, NM 87532
vox/fax 505-753-5913