Chris Schafale on thu 16 oct 03
Ron said once, in reference to iron reds, that although
they may have very low COEs they seldom shiver. I
can't remember if he said why, but this has been my
experience with the other iron reds I have tested. I will
definitely put this one through all the torture tests,
because if it holds up (and comes out this well
consistently, which is perhaps less likely ), it's a
winner.
Chris
On 16 Oct 2003 at 6:48, John Hesselberth wrote:
On Wednesday, October 15, 2003, at 09:13 PM, John
Hesselberth wrote:
> Hi Chris,
>
> This should be a very stable glaze with its good levels of silica and
> alumina.
One additional thought. This glaze does have a very
low calculated
coefficient of expansion--I didn't notice that on the
quick look I took
last night. I would be more concerned about the
potential for
shivering/dunting than lithium leaching. You might want
to do the
freezer to boiling water test a few times.
John
http://www.frogpondpottery.com
http://www.masteringglazes.com
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
Ron Roy on fri 17 oct 03
Hi Chris - you got some memory there - and I do think it would be something
I would say.
As John says - the expansion of that glaze sans iron is quite low and - in
case anyone tries it with say cobalt - they should know about that about
it.
The expansion rate I use for iron is fairly high - so when I add in the 15%
iron the expansion rate becomes quite "normal."
As an interesting side note - when I first saw that recipe I immediately
recognized it as a low expander - gives you some idea about what happens
when you spend so much time calculating glazes. I saw the dolomite and talc
(both sources of MgO - a low expander) the frit (B2O3 a low expander) and
all that silica (a low expander), the spodumene (Lithium is a low expander)
- no spar (KNaO is a high expander) and instantly thought - this is going
to have a low expansion.
It is true that I made that deduction looking at the materials but - if you
don't know what is in those materials you cannot tell that - and if you
have not calculated hundreds of glazes you would still not know that.
Now I know I am a slow learner - and others may be able to do it in a lot
less time that it took me - but the point is - it will happen eventually -
and the sooner it gets started the sooner you will acquire the skills.
I just started in all this about 10 years ago - Imagine how far I would
have gotten if I had started 20 years ago.
RR
>Ron said once, in reference to iron reds, that although
>they may have very low COEs they seldom shiver. I
>can't remember if he said why, but this has been my
>experience with the other iron reds I have tested. I will
>definitely put this one through all the torture tests,
>because if it holds up (and comes out this well
>consistently, which is perhaps less likely ), it's a
>winner.
>
>Chris
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ababi on fri 17 oct 03
Hello Chris
First let me thank you for "griding" this glaze. It was on my mind but
in my condition of work I make the grid rarely.
I wrote your "grided" recipe into Matrix
LAMONT CARAMEL APPLE VARIATION
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Cone 6 1222 deg.C. -
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Ferro 3134 16.00
Dolomite 8.00
Spodumen 16.00
OM-4 Ball Clay 19.00
Bone Ash 5.00
Talc NYtal 4.00
Silica 32.00
Red Iron Oxide 15.00
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Seger Weight%
KNO 0.101 2.11%
CaO 0.535 9.65%
MgO 0.226 2.92%
Li2O 0.138 1.33%
Al2O3 0.307 10.06%
P2O5 0.054 2.45%
B2O3 0.177 3.97%
SiO2 3.482 67.27%
TiO2 0.010 0.24%
K2O 0.008 0.25%
Na2O 0.093 1.86%
Al:Si 11.34
Expan. 5.63
ST 354.25
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Now I add the colorant oxide as a part of the analysis:
Al:Si 11.34
Expan. 6.59
ST 354.25
Ababi Sharon
Glaze addict
Kibbutz Shoval Israel
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910
http://www.matrix2000.co.nz/Matrix%20Demo/Ababi.htm
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Chris
Schafale
Sent: Thursday, October 16, 2003 4:09 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Lamont Caramel Apple variation -- COE issue
Ron said once, in reference to iron reds, that although
they may have very low COEs they seldom shiver. I
can't remember if he said why, but this has been my
experience with the other iron reds I have tested. I will
definitely put this one through all the torture tests,
because if it holds up (and comes out this well
consistently, which is perhaps less likely ), it's a
winner.
Chris
On 16 Oct 2003 at 6:48, John Hesselberth wrote:
On Wednesday, October 15, 2003, at 09:13 PM, John
Hesselberth wrote:
> Hi Chris,
>
> This should be a very stable glaze with its good levels of silica and
> alumina.
One additional thought. This glaze does have a very
low calculated
coefficient of expansion--I didn't notice that on the
quick look I took
last night. I would be more concerned about the
potential for
shivering/dunting than lithium leaching. You might want
to do the
freezer to boiling water test a few times.
John
http://www.frogpondpottery.com
http://www.masteringglazes.com
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
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