The Shelfords on sun 5 oct 97
In case anyone remembers and was interested in this question, I asked Tony
Hansen last week:
> when I run Barnard clay through the Insight program, it appears to
>have a unity formula consistent with being a complete glaze that would
>mature at cone 6. But in fact, as you say, it is only beginning to melt at
>^6. Any idea why the numbers seem to be misleading here?
His answer may be of interest to others like myself who use the calculation
programs without understanding a lot about how they work:
>I figured out your problem with Barnard. You have Fe2O3 set as a flux
>and it's only a flux in reduction. Unset it by double-clicking the
>Fe2O3 line and unsetting it and saving and you'll see that the
>formula will not longer appear similar to a cone 6 glaze.
>
>We will be adding atmosphere-sensitivity to fluxes dependent on
>whether a 'reduction' checkbox is set or not. This will handle
>this situation. Thanks for bringing this to my attention, we'll
>get that feature working as soon as possible.
OK, now - while I was re-setting the Fe2O3 to non-flux in my Insight
program, it occured to me to ask whether there is a quick and dirty
breakdown for rutile that would allow one to recognize the substantial
amount of titanium as a flux in calculating recipes that use a lot of it
(like the ubiquitous floating blue). Would 85% TiO2 and 15% Fe2O3 make
sense (Hamer's rough estimate)? Or 80% to 20% (Conrad)? I understand
that there are lots of other trace minerals in there, but at the moment
NONE of it is being recognized, so at least putting in the Ti and Fe would
have to be an improvement. Of course, this may be something that is
addressed in a later version of Insight, but with what I've got, rutile
doesn't count. Tony? Roy? Tom? Somebody? I'd really appreciate getting
this straight.
- Veronica
____________________________________________________________________________
Veronica Shelford
e-mail: shelford@island.net
s-mail: P.O. Box 6-15
Thetis Island, BC V0R 2Y0
Tel: (250) 246-1509
____________________________________________________________________________
Ron Roy on mon 6 oct 97
Hi Veronica,
I have Rutil entered as 8% iron and 92% Titanium. TiO2 is a glass former
and does not belong with the fluxes.
>----------------------------Original message----------------------------
>OK, now - while I was re-setting the Fe2O3 to non-flux in my Insight
>program, it occured to me to ask whether there is a quick and dirty
>breakdown for rutile that would allow one to recognize the substantial
>amount of titanium as a flux in calculating recipes that use a lot of it
>(like the ubiquitous floating blue). Would 85% TiO2 and 15% Fe2O3 make
>sense (Hamer's rough estimate)? Or 80% to 20% (Conrad)? I understand
>that there are lots of other trace minerals in there, but at the moment
>NONE of it is being recognized, so at least putting in the Ti and Fe would
>have to be an improvement. Of course, this may be something that is
>addressed in a later version of Insight, but with what I've got, rutile
>doesn't count. Tony? Roy? Tom? Somebody? I'd really appreciate getting
>this straight.
>
>- Veronica
>____________________________________________________________________________
>Veronica Shelford
>e-mail: shelford@island.net
>s-mail: P.O. Box 6-15
> Thetis Island, BC V0R 2Y0
>Tel: (250) 246-1509
>____________________________________________________________________________
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 416-752-7862.
Email ronroy@astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
The Shelfords on tue 7 oct 97
Thanks for those replys, me dears. As with all good clayart threads, I now
have more questions than I started with...
First - thanks for the Ti and Fe proportions - you seem to be more or less
agreeing on a 92-94% Titanium and 6-8% Iron breakdown - ignoring the "1%
trace stuff" that Tom mentioned (BTW, wonder why it's called "trace" stuff
if you CAN'T trace it... ok, I know, one could with enormous effort, but
it isn't worth it. Still, English is odd.)
Now, Tom - I guess I wasn't clear in my first message. I meant to convey
that my Hamer and Conrad books were setting rutile at 80-85% TiO2 and
15-20% Iron (as far as I could make out, which may not have been very far.)
Not that I was suggesting a recipe with 80% TiO2. However, you go on to
say:
>At such high
>levels of TiO2, if it were 80% of the glaze mix, then one should expect it
>to behave as a glass-former, not a flux ,
And Ron has also said:
>TiO2 is a glass former
>and does not belong with the fluxes
HELP! Is this another case of something being listed as a flux in the
Insight program because it is one in reduction but not oxidation? (As with
Fe2O3 - see Tony Hansons reply to my Barnard question) Or is it, as I seem
to read into Tom's reply, a case of TiO2 being a glass-former "if it were
80% of the glaze mix" but not necessarily so at more normal (under 10%)
amounts?
Is this why Insight has TiO2 listed as a flux? That is - it may not be one
officially but it acts like one under most conditions?
Tom also says that the Iron in rutile is FeO, not Fe2O3 which is the only
entry for iron in my program. What difference will this make (if any) to
the calculation process, or to the fired effect (cone 6 ox.)? Tom goes on
to say:
>although if the FeO were NOT
>oxidized to Fe2O3 during the run up to C6, then it would start behaving as
>a flux, either in oxidization/neutral condition or in reducing conditions.
I'm not sure I can cope with this. Would it be safe to assume that the
small proportion of FeO in the rutile, which is in it's turn under 10% of
the glaze ingredients, could be just lumped in with the Fe2O3? Or should
it be ignored altogether, and I just list rutile's TiO2 content?
This may be pretty academic - perhaps I needn't worry about it at all. But
a mis-placement of 5-8% of the glaze ingredients as a flux, if they are
not, (or vice versa) can affect the unity formula enough to suggest that a
glaze will mature at a given cone, when in fact it doesn't.
If there is anybody left still reading this, and not bored to distraction,
are there any answers???
Thanks again.
- Veronica
____________________________________________________________________________
Veronica Shelford
e-mail: shelford@island.net
s-mail: P.O. Box 6-15
Thetis Island, BC V0R 2Y0
Tel: (250) 246-1509
____________________________________________________________________________
Karl P. Platt on tue 7 oct 97
> I have Rutil entered as 8% iron and 92% Titanium. TiO2 is a glass former
> and does not belong with the fluxes.
>
> >----------------------------Original message----------------------------
> >OK, now - while I was re-setting the Fe2O3 to non-flux in my Insight
> >program, it occured to me to ask whether there is a quick and dirty
> >breakdown for rutile that would allow one to recognize the substantial
> >amount of titanium as a flux in calculating recipes that use a lot of it
> >(like the ubiquitous floating blue). Would 85% TiO2 and 15% Fe2O3 make
> >sense (Hamer's rough estimate)? Or 80% to 20% (Conrad)? I understand
> >that there are lots of other trace minerals in there, but at the moment
> >NONE of it is being recognized, so at least putting in the Ti and Fe would
> >have to be an improvement. Of course, this may be something that is
> >addressed in a later version of Insight, but with what I've got, rutile
> >doesn't count. Tony? Roy? Tom? Somebody? I'd really appreciate getting
> >this straight.
> >
Can I elaborate a bit here?
TiO2 isn't what we'd really refer to as a "glass former" It will form
glass by itself only under fairly extreme circumstances. Even though its
formula (TiO2) is similar to that of silica (SiO2), the similaraties
largely end there. TiO2 is only slightly soluble in silica based glasses
and for this reason it has long been used as an opacifier in glazes and
enamels -- since deep antiquity.
The presence of TiO2 as an operator in blue glazes has nothing to do with
its being a flux. It only acts as a flux in very high silica melts -- this
is not the case in Ti blue glazes. The rather runny character of these
glazes is owing to the presence of a good bit of B2O3 -- which is
necessary to furnish a chemical environment suited to the development of
Blue in a Ti rich glaze. Ti, to the extent that it can enter a silica rich
glaze, acts to strongly modify the colors given by the 3d transition
elements -- Cr,Mn,Fe,Co,Ni,Cu Also, in combination with CeO2 (about 1wt%
of each) one can obtain interesting yellows.
Rather than do this all again, I'd like to refer the reader to a paper on
this very topic Richard has placed on the ceramics webhe hosts there at
SDSU.
Regards,
KPP
Ron Roy on wed 8 oct 97
Hi Veronica,
TiO2 is a glass former and should not be included in unity with the fluxes.
Just to clarify this in a way that makes sense - it belongs in the RO2
group as does SiO2. I have gotten copies of Insight with oxides included in
unity which should not have been there. I hasten to add - being able to
easily take oxides in and out of unity, and ratio is very important in
glaze calculators. So take the TiO2 out of unity and leave it out. Remember
- after you take it out - save your MDT so it will come up next time with
the TiO2 out of unity.
The ease with which you can include and exclude oxides in a calculation
program is an important factor for me. For instance I have limits for boron
glazes with B2O3 included in unity with the fluxes and out. I check all
boron glazes both ways and it is simple to do.
There is no oxide slot for FeO so you can't include it (or exclude it) -
there should be a place for it. In the case of rutil I don't think it
matters much - just not enough there.
I don't have much experience with other calculators - Would someone else
comment on these features in other programs?
>And Ron has also said:
>>TiO2 is a glass former
>>and does not belong with the fluxes
>HELP! Is this another case of something being listed as a flux in the
>Insight program because it is one in reduction but not oxidation? (As with
>Fe2O3 - see Tony Hansons reply to my Barnard question) Or is it, as I seem
>to read into Tom's reply, a case of TiO2 being a glass-former "if it were
>80% of the glaze mix" but not necessarily so at more normal (under 10%)
>amounts?
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 416-752-7862.
Email ronroy@astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
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