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My second attempt...

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#1 yedrow


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Posted 14 January 2013 - 11:27 PM

I designed these two pretty much from scratch. Again I came up short on the melt and probably need to flux them more. Of course, since I have no idea what I'm doing, I have no idea, lol.

I used the ternary chart Hermes provided but I'm thinking that it was for cone 10 glazes. My flux/alumina/silica numbers came up in the best melt zone. Also, I'm leach testing them overnight. Both mugs are on the same body, and the glazes use the same coloring oxides. The base glazes are quite a bit different though.

Posted Image

#2 Marcia Selsor

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Posted 15 January 2013 - 06:32 AM

Nice looking glazes. Did you soak for .5 hours, 1 hour?
That could help the melt.
I like what looks like the breaking effect on the one on the right. By that I mean it looks like it could change colors over ridges if the melt were a little stronger. Good job!
If they are the same colorants what are they and what is the difference in your base glazes. No need to share the recipe, just curious what you are playing with.

Marcia Selsor, Professor Emerita,Montana State University-Billings

#3 Rebekah Krieger

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Posted 15 January 2013 - 09:37 AM

I am no expert- but I think they look nice! I especially like the creamy one.

~ Namaste ~


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"To me the greatest thing is to live beauty in our daily life and to crowd every moment with things of beauty.  It is then, and then only that  the art of the people as a whole is endowed with it's richest significance.  For it's products are those made by great a many craftsmen for the mass of the people, and the moment this art declines the life of the nation  is removed far away from beauty.  So long as beauty abides in only in a few articles created by a few geniuses, the kingdom of beauty is nowhere near realization."                                                                                 - Bernard Leach 

#4 yedrow


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Posted 15 January 2013 - 10:00 AM

The colorants are RIO, Cobalt Oxide, and Rutile. The real difference between the two is that the one on the right has Spodumene in it. Beyond that I'm just moving the oxides around to get a good fit, and a good melt relative to my expectations and trying to reach a desired zone on Hermes' charts. I'm pretty much staying within the limit formulas but next week I plan on wandering afield a bit. I've been keeping the coloring oxides the same to limit variables, so it is likely they will be variations on a theme. But who knows, I'm learning.

Thanks for the kind words Posted Image


#5 OffCenter


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Posted 15 January 2013 - 10:59 AM

From the picture I can't tell how you "came up short on the flux". It looks fine to me. When you say the same coloring oxides were they the same amounts, too? If so, that is a lot of difference.

E pur si muove.

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

#6 yedrow


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Posted 16 January 2013 - 12:45 AM

Yes Jim, same amounts of the coloring oxides, different base glaze. I must note thought that they aren't so far apart as the cell phone pic. The one on the right picked up some green from the plastic bin next to it. It is a very soft blue.

I did a leach test overnight and both glazes passed. I was concerned the one on the right wouldn't. And, I have yet to make a glass proper. Hermes' ternary graph points to why I think, but I need to make some limits for cone 6 gloss glazes (and figure out how to do so).


#7 JBaymore



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Posted 16 January 2013 - 07:11 AM

I did a leach test overnight and both glazes passed.

Remember that the home kind of leaching tests are only a "rule in" kind of test, not a "rule out". They are not accurate enough to give you data that says "it passes". If you can visually see changes after the home kind of test, then you KNOW it will show leaching of various components on a real standardized lab test. If it "passes" the "home test", that only tells you that is it not totally terrible. It does not mean that ot would not show leaching of some components on a real laborotory testing regime.



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Former Guest Professor, Wuxi Institute of Arts and Science, Yixing, China

Former President and Past President; Potters Council



#8 yedrow


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Posted 16 January 2013 - 09:57 AM

I'll keep that in mind John. The glazes don't have enough cobalt in them to pose much of a risk, at least I don't think so. Considering I left the vinegar on the surface for 24 hours plus, I think I'm probably safe. But you are right, at some point I need to have them tested.


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