mary simmons on wed 1 dec 99
Hi everyone-
I am a recent proud owner of Insight 5.0 software. While I do understand
the concept behind expansion of glazes and clay, I do not understand the
scale of numbers reported by Insight.......and I see that Ron Roy reports
the same kinds of numbers I get---re: Ron's recent post about not being
able to resist simplifying that burgundy satin glaze --where the expansion
was reported as 477.77
What does this mean? How is this number derived.....and what is an
acceptable range of expansion, given this system?
Expansion values reported by others are numbers like 6.71......
?????
Mary
Mary Simmons
Dept of Earth and Planetary Sciences
Northrop Hall
University of New Mexico
Albuquerque, NM 87131-1116
(505)277-9259
piedra@unm.edu
David Hewitt on thu 2 dec 99
Mary,
Your question, to my mind, raises a quite important question. All too
frequently figures for expansion are quoted without giving the units.
I imagine that the 477.77 figure is expansion x10-8 while the 6.71 is
x10-6. It should also say whether it is linear or cubic and say whose
coefficients of expansion are being used so that you know if you are
comparing like with like.
In full the expansion figure should, for example, be given something
like the following:-
6.71 x10-6/oC linear English & Turner
or
20.13 x10-6/oC cubic English & Turner
or, say
811.45 x10-8/oC linear Appen
David
In message , mary simmons writes
>----------------------------Original message----------------------------
>Hi everyone-
>
>I am a recent proud owner of Insight 5.0 software. While I do understand
>the concept behind expansion of glazes and clay, I do not understand the
>scale of numbers reported by Insight.......and I see that Ron Roy reports
>the same kinds of numbers I get---re: Ron's recent post about not being
>able to resist simplifying that burgundy satin glaze --where the expansion
>was reported as 477.77
>
>What does this mean? How is this number derived.....and what is an
>acceptable range of expansion, given this system?
>
>Expansion values reported by others are numbers like 6.71......
>
>
>?????
>Mary
>
>
>
>
>Mary Simmons
>Dept of Earth and Planetary Sciences
>Northrop Hall
>University of New Mexico
>Albuquerque, NM 87131-1116
>
>(505)277-9259
>piedra@unm.edu
>
--
David Hewitt
David Hewitt Pottery ,
7 Fairfield Road, Caerleon, Newport,
South Wales, NP18 3DQ, UK. Tel:- +44 (0) 1633 420647
FAX:- +44 (0) 870 1617274
Own Web site http://www.dhpot.demon.co.uk
IMC Web site http://digitalfire.com/education/people/hewitt.htm
Tom Wirt on thu 2 dec 99
----- Original Message -----
From: mary simmons
Subject: expansion
> ----------------------------Original message----------------------------
> Hi everyone-
>
> I am a recent proud owner of Insight 5.0 software. While I do understand
> the concept behind expansion of glazes and clay, I do not understand the
> scale of numbers reported by Insight.......and I see that Ron Roy reports
> the same kinds of numbers I get---re: Ron's recent post about not being
> able to resist simplifying that burgundy satin glaze --where the expansion
> was reported as 477.77
>
> What does this mean? How is this number derived.....and what is an
> acceptable range of expansion, given this system?
>
> Expansion values reported by others are numbers like 6.71......
>
Mary,
I'd strongly suggest popping for the copy of Tony's companion book..."Magic
of Fire". It's kind of the guidebook for Insight......and a general course
in glaze calc and development.
Tom Wirt
mary simmons on fri 3 dec 99
Tom--Tony's "Magic of Fire" comes with the software. I looked there first.
Mary
At 11:25 AM 12/2/99 EST, you wrote:
>----------------------------Original message----------------------------
>
>----- Original Message -----
>From: mary simmons
>Subject: expansion
>
>
>> ----------------------------Original message----------------------------
>> Hi everyone-
>>
>> I am a recent proud owner of Insight 5.0 software. While I do understand
>> the concept behind expansion of glazes and clay, I do not understand the
>> scale of numbers reported by Insight.......and I see that Ron Roy reports
>> the same kinds of numbers I get---re: Ron's recent post about not being
>> able to resist simplifying that burgundy satin glaze --where the expansion
>> was reported as 477.77
>>
>> What does this mean? How is this number derived.....and what is an
>> acceptable range of expansion, given this system?
>>
>> Expansion values reported by others are numbers like 6.71......
>>
>
>
>Mary,
>
>I'd strongly suggest popping for the copy of Tony's companion book..."Magic
>of Fire". It's kind of the guidebook for Insight......and a general course
>in glaze calc and development.
>
>Tom Wirt
>
Mary Simmons
Dept of Earth and Planetary Sciences
Northrop Hall
University of New Mexico
Albuquerque, NM 87131-1116
(505)277-9259
piedra@unm.edu
Barney Adams on fri 3 dec 99
Mary,
I don't know if you've been replied to off linebut I can try to help.
Ron Roy has his own Materials Data Tables or MDT that he has
built of of all the work and anaysis he's done. The values he represents
for the expansion follows what he is familiar with. The othe values are
the default values given from the Insight MDT. If you ask Ron he will
give you a copy of his MDT which helps when asking him a question
on a glaze. I hope this helps.
Barney
Tom Wirt wrote:
> ----------------------------Original message----------------------------
>
> ----- Original Message -----
> From: mary simmons
> Subject: expansion
>
> > ----------------------------Original message----------------------------
> > Hi everyone-
> >
> > I am a recent proud owner of Insight 5.0 software. While I do understand
> > the concept behind expansion of glazes and clay, I do not understand the
> > scale of numbers reported by Insight.......and I see that Ron Roy reports
> > the same kinds of numbers I get---re: Ron's recent post about not being
> > able to resist simplifying that burgundy satin glaze --where the expansion
> > was reported as 477.77
> >
> > What does this mean? How is this number derived.....and what is an
> > acceptable range of expansion, given this system?
> >
> > Expansion values reported by others are numbers like 6.71......
> >
>
> Mary,
>
> I'd strongly suggest popping for the copy of Tony's companion book..."Magic
> of Fire". It's kind of the guidebook for Insight......and a general course
> in glaze calc and development.
>
> Tom Wirt
David Hewitt on sun 5 dec 99
Mary,
For further reading about expansion data and the different figures that
may be quoted, you might like to look at an article on 'Calculating
Crazing' that is on the Insight web site
http://digitalfire.com/education/people/hewitt.htm
Access is also possible from my own web site 'Pottery Techniques' /
'Calculating Crazing'
http://www.dhpot.demon.co.uk
David
In message , mary simmons writes
>----------------------------Original message----------------------------
>Tom--Tony's "Magic of Fire" comes with the software. I looked there first.
>
>Mary
>
>At 11:25 AM 12/2/99 EST, you wrote:
>>----------------------------Original message----------------------------
>>
>>----- Original Message -----
>>From: mary simmons
>>Subject: expansion
>>
>>
>>> ----------------------------Original message----------------------------
>>> Hi everyone-
>>>
>>> I am a recent proud owner of Insight 5.0 software. While I do understand
>>> the concept behind expansion of glazes and clay, I do not understand the
>>> scale of numbers reported by Insight.......and I see that Ron Roy reports
>>> the same kinds of numbers I get---re: Ron's recent post about not being
>>> able to resist simplifying that burgundy satin glaze --where the expansion
>>> was reported as 477.77
>>>
>>> What does this mean? How is this number derived.....and what is an
>>> acceptable range of expansion, given this system?
>>>
>>> Expansion values reported by others are numbers like 6.71......
>>>
>>
>>
>>Mary,
>>
>>I'd strongly suggest popping for the copy of Tony's companion book..."Magic
>>of Fire". It's kind of the guidebook for Insight......and a general course
>>in glaze calc and development.
>>
>>Tom Wirt
>>
>
>Mary Simmons
>Dept of Earth and Planetary Sciences
>Northrop Hall
>University of New Mexico
>Albuquerque, NM 87131-1116
>
>(505)277-9259
>piedra@unm.edu
>
--
David Hewitt
Ron Roy on mon 6 dec 99
Hi Mary,
Calculated expansion is figured from the % analysis of a fired glaze - Most
calculation programs will give this as well as the molecular formula.
Each oxide is given a value - I use the English & Turner factors which are
quoted by David Hewitt and Mike Baily in their article "Calculating
Grazing" printed in Ceramic Rewiew, vol 113/ 1988.
Not everyone uses the same expansion factors.
The only way to get exact measurements of expansion/contraction is to
actually measure it using a dilatometer.
It does not matter which system you use because these numbers are only used
to tell you if you are going in the "right" direction to say cure crazing.
Even then there are some anomalies with - if not taken into consisderation
will give false information. On the other hand - I need to address hundreds
of fit problems every year and find calculation very useful
If you are looking for the right number for the particular clay you are
using (they are are all at least a little different) you can find that out
by testing glazes with different expansions on that body.
For many cone 6 bodies a glaze expansion of 450 will work just fine - but
that will change depending on many factors - which determine the expansion
of the fired clay.
Some factors which determine clay expansion (mainly free silica and
cristobalite) are complicated and cannot be calculated.
OK?
>----------------------------Original message----------------------------
>Hi everyone-
>I am a recent proud owner of Insight 5.0 software. While I do understand
>the concept behind expansion of glazes and clay, I do not understand the
>scale of numbers reported by Insight.......and I see that Ron Roy reports
>the same kinds of numbers I get---re: Ron's recent post about not being
>able to resist simplifying that burgundy satin glaze --where the expansion
>was reported as 477.77
>
>What does this mean? How is this number derived.....and what is an
>acceptable range of expansion, given this system?
>
>Expansion values reported by others are numbers like 6.71......
>Mary
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
mary simmons on fri 10 dec 99
OK, Ron!! Thanks for the explanation about expansion values..
On that analysis that totaled 104%--
The analysis reported very high SiO2 (72%) which is the likely suspect that
pushed the analysis over 100%--any time that Si is over about 70% in an XRF
analysis, it can be off by as much as 3%. More than likely the trace
elements that are in EVERYTHING account for a % or so of the total.
OTherwise, machines being what they are (imperfect), it is entirely
probable that part of this error is due to the limits of the XRF.
To get a REAL accurate analysis of the silica content, you use a
gravimetric method, that does not rely on miracles of modern technology,
but on dissolution of everything that is NOT Si02, and then heat, and
weighing. I've never personally done this--it is very time consuming, but
it is EXTREMELY accurate
cheers-
Mary
At 03:54 PM 12/6/99 EST, you wrote:
>----------------------------Original message----------------------------
>Hi Mary,
>
>Calculated expansion is figured from the % analysis of a fired glaze - Most
>calculation programs will give this as well as the molecular formula.
>
>Each oxide is given a value - I use the English & Turner factors which are
>quoted by David Hewitt and Mike Baily in their article "Calculating
>Grazing" printed in Ceramic Rewiew, vol 113/ 1988.
>
>Not everyone uses the same expansion factors.
>
>The only way to get exact measurements of expansion/contraction is to
>actually measure it using a dilatometer.
>
>It does not matter which system you use because these numbers are only used
>to tell you if you are going in the "right" direction to say cure crazing.
>Even then there are some anomalies with - if not taken into consisderation
>will give false information. On the other hand - I need to address hundreds
>of fit problems every year and find calculation very useful
>
>If you are looking for the right number for the particular clay you are
>using (they are are all at least a little different) you can find that out
>by testing glazes with different expansions on that body.
>
>For many cone 6 bodies a glaze expansion of 450 will work just fine - but
>that will change depending on many factors - which determine the expansion
>of the fired clay.
>
>Some factors which determine clay expansion (mainly free silica and
>cristobalite) are complicated and cannot be calculated.
>
>OK?
>
>>----------------------------Original message----------------------------
>>Hi everyone-
>>I am a recent proud owner of Insight 5.0 software. While I do understand
>>the concept behind expansion of glazes and clay, I do not understand the
>>scale of numbers reported by Insight.......and I see that Ron Roy reports
>>the same kinds of numbers I get---re: Ron's recent post about not being
>>able to resist simplifying that burgundy satin glaze --where the expansion
>>was reported as 477.77
>>
>>What does this mean? How is this number derived.....and what is an
>>acceptable range of expansion, given this system?
>>
>>Expansion values reported by others are numbers like 6.71......
>>Mary
>
>Ron Roy
>93 Pegasus Trail
>Scarborough
>Ontario, Canada
>M1G 3N8
>Evenings 416-439-2621
>Fax 416-438-7849
>
Mary Simmons
Dept of Earth and Planetary Sciences
Northrop Hall
University of New Mexico
Albuquerque, NM 87131-1116
(505)277-9259
piedra@unm.edu
Ron Roy on thu 16 dec 99
Thanks Mary,
I'm going to pass your info on to Tony H and Gavin if you don't mind - I am
noticing a lot of varyation in some of the tests I am having done and I
find it disconcerting.
Do you have a chance to get any such work done where you are working? I
would find it very helpful of I could have some materials reported on. I
know I am asking a lot but we potters have to learn by hook or by crook you
know.
RR
>----------------------------Original message----------------------------
>OK, Ron!! Thanks for the explanation about expansion values..
>
>On that analysis that totaled 104%--
>
>The analysis reported very high SiO2 (72%) which is the likely suspect that
>pushed the analysis over 100%--any time that Si is over about 70% in an XRF
>analysis, it can be off by as much as 3%. More than likely the trace
>elements that are in EVERYTHING account for a % or so of the total.
>OTherwise, machines being what they are (imperfect), it is entirely
>probable that part of this error is due to the limits of the XRF.
>
>To get a REAL accurate analysis of the silica content, you use a
>gravimetric method, that does not rely on miracles of modern technology,
>but on dissolution of everything that is NOT Si02, and then heat, and
>weighing. I've never personally done this--it is very time consuming, but
>it is EXTREMELY accurate
>
>cheers-
>Mary
>
>At 03:54 PM 12/6/99 EST, you wrote:
>>----------------------------Original message----------------------------
>>Hi Mary,
>>
>>Calculated expansion is figured from the % analysis of a fired glaze - Most
>>calculation programs will give this as well as the molecular formula.
>>
>>Each oxide is given a value - I use the English & Turner factors which are
>>quoted by David Hewitt and Mike Baily in their article "Calculating
>>Grazing" printed in Ceramic Rewiew, vol 113/ 1988.
>>
>>Not everyone uses the same expansion factors.
>>
>>The only way to get exact measurements of expansion/contraction is to
>>actually measure it using a dilatometer.
>>
>>It does not matter which system you use because these numbers are only used
>>to tell you if you are going in the "right" direction to say cure crazing.
>>Even then there are some anomalies with - if not taken into consisderation
>>will give false information. On the other hand - I need to address hundreds
>>of fit problems every year and find calculation very useful
>>
>>If you are looking for the right number for the particular clay you are
>>using (they are are all at least a little different) you can find that out
>>by testing glazes with different expansions on that body.
>>
>>For many cone 6 bodies a glaze expansion of 450 will work just fine - but
>>that will change depending on many factors - which determine the expansion
>>of the fired clay.
>>
>>Some factors which determine clay expansion (mainly free silica and
>>cristobalite) are complicated and cannot be calculated.
>>
>>OK?
>>
>>>----------------------------Original message----------------------------
>>>Hi everyone-
>>>I am a recent proud owner of Insight 5.0 software. While I do understand
>>>the concept behind expansion of glazes and clay, I do not understand the
>>>scale of numbers reported by Insight.......and I see that Ron Roy reports
>>>the same kinds of numbers I get---re: Ron's recent post about not being
>>>able to resist simplifying that burgundy satin glaze --where the expansion
>>>was reported as 477.77
>>>
>>>What does this mean? How is this number derived.....and what is an
>>>acceptable range of expansion, given this system?
>>>
>>>Expansion values reported by others are numbers like 6.71......
>>>Mary
>>
>>Ron Roy
>>93 Pegasus Trail
>>Scarborough
>>Ontario, Canada
>>M1G 3N8
>>Evenings 416-439-2621
>>Fax 416-438-7849
>>
>
>Mary Simmons
>Dept of Earth and Planetary Sciences
>Northrop Hall
>University of New Mexico
>Albuquerque, NM 87131-1116
>
>(505)277-9259
>piedra@unm.edu
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
| |
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