Hank Murrow on thu 23 aug 01
Bamboo Karen wrote;
>My question is about the use of lithium feldspars...
>What determines the difference in use of the following,
>spodumene,
>petalite,
>macaloid
>
>I have a sense that it is a matter of the silica molecules....
>but is there some simple logic to using different sources
>for lithium...
>I guess quality of surface in the glaze or as in spodumene
>in shino...the orange flashing.
>thanks,
>bamboo karen in search of a lithium guru with Leonora
>thanks
Well;
While no guru, I have been using Lithium compounds since my school
days @ U of Oregon in '58. The material of choice in those days was
Lithospar, a 'manufactured' lithium feldspar from Spruce Pine, NC. We used
Lithium carb for low temp copper blues, too.
During my short but happy career in teaching at Ohio U in Athens
and Anderson Ranch; I ran the supplier guys in circles trying to get
lithium-bearing materials in stock. Then the magic material was Lepidolite
and its 'manufactured' substitute Litholite 400. The embargo on the good
stuff from Africa ended that.
Nowadays, I love spodumene from down under, spodumene from Canada
(Low Melt Spod from Tanco), and the good old foote 'dirty' spodumene from
old stock. When I want 'dangerous' shinos I use the dirty spod. When I want
the Phosphorus along with the Li I use the Low Melt, and the aussie
'Gualia' is great too. Lepidolite brings in sodium, while petalite is just
a Li feldspathoid. Macaloid has no Li content, but helps suspend those
glazes that need it. Li and P205 are great aids in getting the various
indian-iron reds, re: the P205 in Shaner's Red.
And while you are looking around, check out my article, "Shinos in
the Fire...an Odyssey" in the 'back to school' issue of CM.
good Hunting! Hank in Eugene
Karen Sullivan on thu 23 aug 01
My question is about the use of lithium feldspars...
What determines the difference in use of the following,
spodumene,
petalite,
macaloid
I have a sense that it is a matter of the silica molecules....
but is there some simple logic to using different sources
for lithium...
I guess quality of surface in the glaze or as in spodumene
in shino...the orange flashing.
thanks,
bamboo karen in search of a lithium guru with Leonora
thanks
on 8/23/01 6:41 AM, Leonora Coleman at leonorac@MINDSPRING.COM wrote:
> I have a practical question about the use of lithium carbonate in glazes.
> I am mixing some glaze tests includiong Lithium carbonate in the recipe. The
> lithium carbonate remains very grainy in the glaze mix and doesn't want to go
> through even a 40 mesh screen. I have let it sit for more than a week and it
> still doesn't break down sufficiently to sieve to a uniform consistency.
> What is the solution to this problem, short of using a ball mill, which I do
> not have?
>
> Leonora at Claymakers in Durham, NC
>
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Ron Roy on tue 28 aug 01
If you are looking for lithium oxide Spodumene has more than Petalite.
Mackaloid is not a source.
Petalite has relatively little iron - some spods have more - the more iron
the more red in shino.
Looks to me that the Aussi spod is the most iron free - and the old non
deironed Foote had the most. Tanko spod has more than the Aussi.
RR
>My question is about the use of lithium feldspars...
>What determines the difference in use of the following,
>spodumene,
>petalite,
>macaloid
>
>I have a sense that it is a matter of the silica molecules....
>but is there some simple logic to using different sources
>for lithium...
>I guess quality of surface in the glaze or as in spodumene
>in shino...the orange flashing.
>thanks,
>bamboo karen in search of a lithium guru with Leonora
>thanks
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
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