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bisque blushing from terra sig

updated sun 15 apr 01


Jim and Marge Wade on thu 12 apr 01

Just a quick question I hope someone can answer for me. I just unloaded my
first bisque firing of pots with terra sig. I applied red art, gold art and
ball sigs to some of the pots when they were bone dry and burnished them.
Some of the pots (made from a low fire white clay) did not have sig on and
of these all but one were burnished. What I found was that the pots that
were burnished but did not have the sig applied seemed to pick up a faint
blush of the red art sig while the one pot that was not burnished (and no
sig) remained bright white. My test pots made from porcelain were
unburnished on the inside, but the sig that was applied to the exterior was
burnished. The inside of these pots were also bright white; only the low
fire white pots that were burnished (no sig first) have this blushing. Has
anyone expierenced this? Should I have fired the red art sig pieces by
themselves and not have included any pots that are only burnished? I like
the contrast of black and white in my sawdust firings, but am also
interested in experimenting with the earthtones that I hope to get when
using various sigs. I also want to try saggar firing. I'm not sure how these
peach colored pots will turn out when I sawdust or saggar fire them -
certainly not the white/black I was expecting. It did not seem to matter
where the pots were in the kiln; with or without a red art sig pot on the
same shelf or not. I fire in and electric kiln, if that makes a difference.

Any input would be greatly appreciated.


Jim and Marge Wade on fri 13 apr 01

Yes, I did do most of the burnishing with a spoon (simple stainless from the
kitchen, not silverplated or anything like that). I'll try yout suggestion
and see if the metal may have caused the blushing. Thanks.


> Question:
> Did you burnish with a metal tool? ...

> Michael Wendt

Michael Wendt on fri 13 apr 01

Did you burnish with a metal tool? Even though sig is very smooth, it can
still abrade fine metal on the surface. A quick way to see if this is the
cause is to burnish half a pot with your tool and leave the other half
unburnished. I made a burnishing tool of glazed stoneware for critical sites
where no metallic contamination is wanted.
Michael Wendt