Levesque-OBrien on mon 18 may 98
A question came up in one of those discussions around a wood kiln. By
adding LicO3 to a porcelain body, (.5%), it created very interesting
surfaceeffects, due to fluxing of the clay. However, it was almost
impossible to throw, due to what appeared to be a deflocculated state. It
was a very throwable body before this. It was almost thixotropic. So.
What is the solution? Using Spodumene has been tried and tested at various
% and is not a solution. The surface effects are due directly to the LiCO3,
and would like to be kept. Suggestions???
Ron Roy on tue 19 may 98
The effect is due to the partial solubility of lithium carb - Because it is
an alkaline it deflocculates clay and glazes very well. You could get the
same effect from soda ash (sodium Carb.) but much less would be needed
because it is all soluble.
The Spodumene did not work because the lithium was not in a soluble form.
Perhaps spraying some lithium carb solution on the pot before firing will
give the same result. To make the solution use hot (really hot) water and
Li2CO3. Using Lithium carb is this way and with glaze will probably result
in some sever glaze/clay misfits and I don't recommend it. In fact - using
lithium carb in glazes is not something I recommend at all.
BEWARE - ingestion or breathing of lithium can have dangerous consequences.
As the clay dries the soluble salts are left on the surface of the ware -
migrating there as the clay dries. If the pot is upright the salts will
tend to accumulate on the upper part. If wax is applied - before drying -
the soluble salts will not be deposited where the wax is - because there
will be no evaporation at those places.
If you want to put something in the clay (think of this as self glazing
clay - like Egyptian paste) I suggest using other solubles that won't
defloculate - boric acid might work - and so might epson salts. I am over
my head in this particular area - perhaps others will have some
suggestions.
Note: spelling below should be not LicO3 but rather Li2CO3
>----------------------------Original message----------------------------
>A question came up in one of those discussions around a wood kiln. By
>adding LicO3 to a porcelain body, (.5%), it created very interesting
>surfaceeffects, due to fluxing of the clay. However, it was almost
>impossible to throw, due to what appeared to be a deflocculated state. It
>was a very throwable body before this. It was almost thixotropic. So.
>What is the solution? Using Spodumene has been tried and tested at various
>% and is not a solution. The surface effects are due directly to the LiCO3,
>and would like to be kept. Suggestions???
Ron Roy
93 Pegasus trail
Scarborough Otario
Canada M1G 3N8
Phone: 416-439-2621
Fax: 416-438-7849
Web page: Home page http://digitalfire.com/education/people/ronroy.htm
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