Gary Hermanson on tue 17 sep 96
Soldner Halo
A while back there was some Raku discussion on how to achieve the "Soldner halo"
effect. Two of the recipes listed consisted of equal parts red iron oxide plus
either copper carbonate or manganese dioxide. When brushed on a pot it yields a
black spot surrounded by a white halo.
My question is: Is the pot pulled from the kiln and put into a post firing
reduction container or just pulled out and left to cool in the atmosphere? i.e.
is the white halo the result of the pot resisting carbon impregnation or not
having been smoked?
Thanks
Gary Hermanson
San Diego
lrh on wed 18 sep 96
Hello, or is it Halo
In my experience, the halo is the result of the migration of
water soluable materials away from the edge of the solids in
the glaze mix. This creates ring around the glaze edge that
resists the penitration of reduction materials, looking like a halo.
This effect is both time dependent and degree of reduction dependent.
To get the best halos, reduce just heavy enough and just long enough
to develop light blacks. More than this will overcome the soluable
materials resistance, and the halo will will blacken.
Loran Hill
______________________________ Reply Separator _________________________________
Subject: Soldner Halo
Author: Ceramic Arts Discussion List at ccmgate
Date: 9/17/96 6:20 PM
----------------------------Original message----------------------------
Soldner Halo
A while back there was some Raku discussion on how to achieve the "Soldner halo"
effect. Two of the recipes listed consisted of equal parts red iron oxide plus
either copper carbonate or manganese dioxide. When brushed on a pot it yields a
black spot surrounded by a white halo.
My question is: Is the pot pulled from the kiln and put into a post firing
reduction container or just pulled out and left to cool in the atmosphere? i.e.
is the white halo the result of the pot resisting carbon impregnation or not
having been smoked?
Thanks
Gary Hermanson
San Diego
K. Lorensen on thu 19 sep 96
Gary,
I have attended Raku workshops where this effect was
achieved. The piece was handled like all other Raku
pieces, placed in a reduction chamber (though this
artist did not later cool in water - claimed he saw
no benefit on any pots).
Hope this limited info helps,
Carie Lorensen
Seattle, WA
LizzardOL@aol.com on sun 22 sep 96
I just went to a Soldner workshop recently - at the recommendation of someone
here on clayart, as I recall....as a by-product of an earlier thread on
Soldner Halo. Paul suggested two ways to achieve the halo (according to my
scribbled notes).... 1) "smoke it hard" (the piece) "until a lighter yellow
smoke appears", then let a little air in, followed by more reduction or 2)
after reduction, pull the pot through the burning flames and "let the
iron/copper stain "burn off at the edges". Then quench the pot or put it in
an air tight container to stop the oxidation.
Paul seemed to imply that the slip would oxidize at the edges first (why, I
now wonder) if removed from reduction and if left in oxidation too long the
entire area covered with slip would turn light.
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