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Percentages of iron oxide


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#1 Vcope

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Posted 27 September 2012 - 12:26 AM

We have access to 99% iron oxide through our closest supplier, however we find that 84% works better to get the best contrasts in our Temoku glaze. When looking at glaze formulas in texts and journals the percent content is usually not highlighted. We have found that Spanish RIO is not a direct substitution. I am just asking for clarification which iron is the best choice for trying out new glaze recipes.
Thank you for any information about this question.
V

#2 Mark C.

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Posted 27 September 2012 - 01:27 AM

I have been using spanish for many years now-before that The domestic was all I ever saw.
I also have used High Purity from US Pigments as well.
Back in the day Domestic was all that I recall was around.So we always used that in all recipes.
Now its spanish or High Purity for me.
Mark
Mark Cortright
www.liscomhillpottery.com

#3 neilestrick

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Posted 27 September 2012 - 09:20 AM

The cheap domestic stuff will work fine, unless otherwise specified in the recipe.
Neil Estrick
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#4 JBaymore

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Posted 27 September 2012 - 10:09 AM

Test it.

best,

.........................john
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Professor of Ceramics; New Hampshire Insitute of Art

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#5 neilestrick

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Posted 27 September 2012 - 11:59 AM

Test it.

best,

.........................john


That's your answer to everything.Posted Image
Neil Estrick
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#6 JBaymore

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Posted 27 September 2012 - 01:58 PM


Test it.

best,

.........................john


That's your answer to everything.Posted Image



That IS the answer to everything. ;)

best,

......................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#7 neilestrick

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Posted 27 September 2012 - 02:47 PM

My students get frustrated with me because my answer to their questions is usually "it depends".
Neil Estrick
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#8 JBaymore

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Posted 27 September 2012 - 03:16 PM

My students get frustrated with me because my answer to their questions is usually "it depends".


Ditto. It is the correct answer to EVERY question about ceramics. ;)

best,

.........................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

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#9 TJR

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Posted 27 September 2012 - 10:22 PM


Test it.

best,

.........................john


That's your answer to everything.:D

Neil;
You know that you test everything as well. You are a bit of a glaze god yourself.[I almost typed teat there]
I still have the oldest Brent CXC:D:blink:B):P

#10 clay lover

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Posted 29 September 2012 - 11:12 AM

I have been using spanish for many years now-before that The domestic was all I ever saw.
I also have used High Purity from US Pigments as well.
Back in the day Domestic was all that I recall was around.So we always used that in all recipes.
Now its spanish or High Purity for me.
Mark


Is High Purity the same as what I see mentioned in recipies as 'Special" ?
Will higher purity improve any glaze it is used in, or only if asked for? I know a potter that insists it should always be used instead of the regular less expensive.

#11 OffCenter

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Posted 30 September 2012 - 08:45 AM


I have been using spanish for many years now-before that The domestic was all I ever saw.
I also have used High Purity from US Pigments as well.
Back in the day Domestic was all that I recall was around.So we always used that in all recipes.
Now its spanish or High Purity for me.
Mark


Is High Purity the same as what I see mentioned in recipies as 'Special" ?
Will higher purity improve any glaze it is used in, or only if asked for? I know a potter that insists it should always be used instead of the regular less expensive.


As always it depends on the glaze. I've been testing RIO, Spanish RIO, Crocus M., and High Purity RIO in various Iron Saturate glazes. So far what I've found is that regular RIO looks a tad better in glazes such as Jen's Juicy Fruit with Iron and Bailey's Red than High Purity RIO. I think that may be simply because the purer the iron is, the stronger it is in a glaze so maybe a tad less High Purity RIO works as well as regular RIO. In some iron saturates High Purity RIO tends to speckle a little more than regular RIO. So far, Crocus M doesn't look good subbed for RIO. Too dark. In some glazes Spanish RIO looks much better than any other form of Iron. It's well worth the time and money to get all 4 (and others such as Yellow Iron and Yellow Ochre) and test test test.

I tried to upload a pic of a test tile that compares regular RIO and High Purity RIO but no matter how small I make the picture I get an error message saying the file it too big!

Jim
E pur si muove.

"But it does move," said Galileo under his breath.

#12 Mark C.

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Posted 30 September 2012 - 11:56 AM

Using less high purity does do the same thing as as regular red iron-You will discover regular is the best deal for most applications.
If you are using it as a smeared stain on raw clay with no glaze covering then the various kinds look a bit different-Test test test as Johns mantra says.
Mark
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#13 clay lover

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Posted 30 September 2012 - 12:04 PM

Thanks for the answers, guys.
I was having a hard time believing this potter when he said 1 thing was the answer for all questions, even I know that is rarely true in pottery.

#14 JBaymore

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Posted 30 September 2012 - 06:56 PM

I was having a hard time believing this potter when he said 1 thing was the answer for all questions, even I know that is rarely true in pottery.


When you hear someone say that "there's only one way"....... they do not yet know enough to know what they do not know. Take things they say with a grain of salt. ;)

best,

....................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com




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