iandol on sun 16 dec 01
Dear Jonathan Kaplan
You say <carbonate for the lithium carbonate in a certain ratio,>>
Perhaps you would explain the technology and science behind your =
thinking here.
I ask because it seems incongruous to replace compounds of the Alkali =
Metal Element Oxides with compound containing Alkali Earth Element =
Oxides, considering that the former (Li, K, Na) are well known as =
providers of low melting point compounds which become solvents for the =
other ingredients, whereas the latter, as oxides derived from carbonates =
(Mg,Ca, Ba, Sr) are highly refractory and need a solvent to bring them =
into solution so that they can contribute to the formation of a glass or =
material material with a vitreous structure.
Having said that, I fully support your suggestion that people should =
explore the range of frits which are available. I am certain many of =
these would extend the Cone 6 palette well beyond its current limited =
scope and might lead to some interesting discoveries and inventions.
Trusting that Joyce is able to follow the arguament.
Best regards,=20
Ivor Lewis. Redhill, South Australia
Khaimraj Seepersad on mon 17 dec 01
Hello to All ,
Ivor ,
A few points -
[1 ] When I monkeyed around with Li20 , I did come
across mixes that did not give glass , but
devitrified.
[2 ] There is a Eutectic for Sr0 / B203 that gives
a glass at 890 deg.c.
Making mix of the Alkaline Metals drops this temperature
further to 650 deg.c and 700 deg.c
Adding Si02 stiffens the melt and flow , but the same
result occurs , just needing a soak to achieve it.
[3] J.Chappell - Clay and Glazes - 1991 -
Suggests Pemco - 930 , for use in the 06 to 02 range.
I believe it has 17.3 % Sr0
[4] I revamped some old glazes in Parmelee and
Ceramic Glazes [ Borax Co. ]
To work with this idea. I have not got around to using
the Mannitol [ mannisol ? ] test from Vogel for B203.
Which would be the only "toxic " oxide in the group
I am using.
[5] There is a variant on a commercial frit [ illegal to
say ] that uses on Alkaline Earth , B203 , Si02 and
a stabiliser , that flows to a satin gloss at 850 deg.c
requiring no Alkali's .
It is especially hard , and with further combination
of kaolin , 10 % Nc4Feldspar [ not needed if you go
higher than 980 deg.c , heat takes over ] , will get
harder still.Yet remain glossy to satin glossy.
[ Still to test for B203 ]
[6] As usual the addition of Ti02 and exclusion of
all, but 1 % Al203 , will allow amazing mixes of
alkaline earths , especially Mg0.
[7] I was able to multiple metal mix a Borate that
used only 23 % B203 [ as the only glass former ]
but it was a dead end as the glass fell apart from
exposure to 3 days of 5% Acetic Acid.
[8] I reformed the standard Eutectic for
Pbo/Al203/Si02 - 650 deg.c .
Using a multiple metal mix [ lowest alkali ] and
ended up 10deg.c lower and 10 deg.c higher
than the eutectic .
I failed to shield the B203 from 5 % Acetic Acid
as the glass disrupted after 7 days.
[ Still trying ].
I believe we may think along similar lines as I use
the multiple metals "dissolved " in a lower melting
material.
As to the eutectics - which does something funny
to your nose - I worry only about inducing an
early melt , maintaining the gloss and clear of the
frit and if it achieves the temperature objective.
i.e melts when I want it to and does not devitrify.
It is possible to replace Alkalis with B203 , for
lower melting and gloss . It may even make a
stronger glaze as the combination of Alkali/B203
may have the same problems Pbo / B203 seems
to have had. I think Parmelee speaks of this.
[ I can offer nothing positive until I do the B203
solubility tests.]
The alkaline earth /B203 combination is I believe
is made more insoluble with the addition of Si02 and
possibly Ti02 , at higher temperatures.
Lower temperatures with alkalis/B203 we are shielding
with Si02 /Ti02.
But this is bit bit reading , seen through many books
and I cannot quote pages.
We can however look at Sinhalite or a few other natural
rock combinations , using B203 .
Do you know if Alloys made with Ti02 and Na20 are stable
to mositure or water ?
As far as I have read , Si02 cannot hold Na20 , always water
soluble ?
Khaimraj
* Ps. have you any knowledge of Alloys ?
Can I alloy Tin and Titanium , or Gold and Titanium or
Silver and Titanium ?
-----Original Message-----
From: iandol
To: CLAYART@LSV.CERAMICS.ORG
Date: 17 December 2001 5:03
Subject: Ceramic Glaze Ingredients: Lithium substitution incongruity
Dear Jonathan Kaplan
You say <for the lithium carbonate in a certain ratio,>>
Perhaps you would explain the technology and science behind your thinking
here.
I ask because it seems incongruous to replace compounds of the Alkali Metal
Element Oxides with compound containing Alkali Earth Element Oxides,
considering that the former (Li, K, Na) are well known as providers of low
melting point compounds which become solvents for the other ingredients,
whereas the latter, as oxides derived from carbonates (Mg,Ca, Ba, Sr) are
highly refractory and need a solvent to bring them into solution so that
they can contribute to the formation of a glass or material material with a
vitreous structure.
Having said that, I fully support your suggestion that people should explore
the range of frits which are available. I am certain many of these would
extend the Cone 6 palette well beyond its current limited scope and might
lead to some interesting discoveries and inventions.
Trusting that Joyce is able to follow the arguament.
Best regards,
Ivor Lewis. Redhill, South Australia
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