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Post by mohawkpiper on Oct 22, 2017 14:06:59 GMT -6
My first matte glazes tests... Thoughts? They're kinda satin i guess really. G
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Post by tileman2 on Oct 22, 2017 17:41:34 GMT -6
Look good to me. Uniform appearance. I have seen mattes have patches of varying sheen: do not see that here.
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gczop
Full Member
Posts: 202
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Post by gczop on Oct 23, 2017 8:18:45 GMT -6
Greg, Like the effect, reminiscent of Ru ware celadon. With that surface, how will it behave in a post firing reduction? Gordon
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annie
Junior Member
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Post by annie on Oct 24, 2017 9:54:13 GMT -6
They look pretty good Greg. Especially like the one with grey crystals.
--Annie
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Post by rebeccavatar on Oct 31, 2017 17:16:07 GMT -6
Hello, I am a ceramicist from Germany and I have only recently started to read up on crystalline glazes. I am already fascinated by the topic and glad to have found this forum as there is very little information available in German. One thing really puzzles me though. I have seen hundreds of images of typical glossy crystalline glazes and seen dozens of variations on the typical ferro frit 3110 recipe. But I am much more enamoured with matte crystalline glazes like yours. Yet I cannot seem to find much information on them. Are these basically the same as the glossy glazes with just a difference in firing schedule? Or are they based on completely different recipes? Or is just a slight change to a glossy recipe needed to matte them? I found a recipe on digitalfire for a matte crystalline base with wollastonite and very little of a frit I never heard of before. But as there is no picture of this glaze I am not sure it is what I am looking for. I woukd be ever so grateful for a pointer in the right direction! Your cups are absolutely stunning by the way. I love the milky, soft colours.
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Post by bill2015 on Nov 4, 2017 6:49:47 GMT -6
Here are two matte crystalline glazes, cone 10, from Ted Secomb, Australian artist, that uses no frits: Potash feldspar 35 Dense Zinc Oxide 20 (I believe this should be Denox brand calcined zinc oxide) Barium Carbonate25 Lithium Carbonate 3 Kaolin 2 Silica 15 Titanium dioxide 5
Nephelinesyenite33.3 Barium carbonate 23.2 Dense Zinc Oxide 19.2 (Denox) Lithium Carbonate 2.0 Titanium Dioxide 5.1 Silica 17.2
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Post by rebeccavatar on Nov 4, 2017 12:39:10 GMT -6
Hello Bill2015, Thank you ever so much for the information. It is very kind of you to have taken the time to post this. Have a wonderful weekend and greetings from Germany.
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Post by mohawkpiper on Nov 5, 2017 19:18:23 GMT -6
Hi Rebecca, Sorry for the late reply. I get busy sometimes. I'm not really sure but i think most mattes are like what Bill posted, or yea, some other odd frit or something. I'm super new to mattes so I don't really know, but I'm trying an entirely different route before attempting recipes for mattes found online and then altering them. I'm not quite ready to say what i'm doing yet. Maybe it's more obvious than I think. These two tests are 3110 fritted.
Gordon... I've been meaning to do a post fire reduced one... just haven't found the time yet. I have something in mind tho.
G
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Post by serian on Nov 6, 2017 8:26:05 GMT -6
Hi Rebecca,
Most matt crystal glazes are zinc barium glazes. Depending on the ratio of zinc to barium, visible zinc silicate crystals form in a matt ground of not visible tiny barium silicate crystals, which make the glaze matt. At higher barium content, visible barium silicate crystals or barium-zink-silikates (with different possible mineralogy) maybe formed on a matt ground, which can turn pink together with nickel. This is the difficult high art of zinc barium glazes ... My zinc barium crystal glazes form zinc silicate crystals on a very pleasant matt base as described above.
I'm happy to get even larger single crystals in this type of glaze than mostly usual. If I burn classic glossy zinc crystal glazes in a second firing (in a pre-firing of not yet glazed ceramic) at 950° C, sometimes such pieces are getting also matt.
But this kind of matt is quite different from that of zinc barium glazes. The pleasant feeling of touching them is unique with zinc barium glazes.
Rather usually with smaller crystals and without coloring oxides:
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gczop
Full Member
Posts: 202
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Post by gczop on Nov 6, 2017 8:45:39 GMT -6
Lovely, Serian I've been playing with cone 10 glazes 50% BaCO3 and 50% Neph Sy or Spodumene with copper to get the Han blue. Not ready for prime time yet. Serian's accomplishments with the Ba Zn combination are remarkable. For wonderful crystalline matts see John Tilton. (eg.recipies Diane Creber's book). Cheers Gordon
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Post by rebeccavatar on Nov 7, 2017 17:25:04 GMT -6
Hello, Thanks to everyone who replied to my question, especially to Serian. That was a very comprehensive explanation! It was actually better than the text on Zinc Barium Glazes in my glaze chemistry book. This textbook I have is THE go to literature on glazes in Germany but it does not focus on crystalline glazes and has only a small chapter on Zinc Barium with a couple of recipes. You inadvertently answered another question which was bugging me. Actually John Tilton is the reason I first got interested in matte crystalline glazes. I came across his work online and my jaw dropped. The way his pots look like they are covered with exotic lichen, treebark or frost or just something straight from nature... some of his glazes are reminiscent of weathered stones, others of alien landscapes... I suspected they might be Zinc Barium glazes and not just matte "regular" crystalline gazes but I wouldn't have known who to ask about this. After all it could be considered rude to ask an artist how he goes about accomplishing his art. All the nicer of you, to explain. I absolutely LOVE the colors in your last picture. That is just so pretty, the tiny crystals in the background give these glazes so much depth... you could look at them for hours. The second of the long necked vases is also especially beautiful to me... and the first of the cups... and the third... Ha ha, every piece you posted is stunning. I love how the "background" of the glaze in some pieces would constitute an interesting surface all by itself. I now know exactly what I want to achieve some day. I just have to start very slowly with the recipes in my book... because my kiln is not made for cone 10 crystalline firings. That would be too much strain on the elements. I also cannot at this point switch to porcelain, that would be too many new factors all at once. But in my book there are recipes for cone 6. I will start with them and see how far I get. You have been of great help! PS There is another artist whose work I greatly admire. Not just her glazes, but the how they compliment her forms as well: Gwendolyn Yoppolo. I suspect her glazes are Zinc Barium glazes as well... although her surfaces are no where near as spectacular as yours, Serian, I find them very beautiful. I can't wait to fire my first slow cooling kiln loaded with glaze tests. I have already begun mixing.
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Post by mohawkpiper on Nov 14, 2017 18:15:33 GMT -6
Gordon, Post fire reduced... in different lighting environments. Kinda not what I was expecting.... softer... subtler... but still nice. G
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gczop
Full Member
Posts: 202
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Post by gczop on Nov 16, 2017 9:08:45 GMT -6
Hi Greg, They are unique and yes, entirely unexpected. Thanks. Gordon
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Post by mohawkpiper on Nov 16, 2017 13:08:14 GMT -6
Hey Gordon, sometimes i read back on my posts and realize i may not have worded everything properly... just to be clear, this most recent one is NOT the same glaze as either of the two initial tests. I dont like the way the glaze looks like in post fire reduction when it has as much copper as the first two tests have in them.... so the last image of the post fire reduced matte one is an entirely different glaze.
G
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Post by bill2015 on Nov 28, 2017 9:30:03 GMT -6
rebeccavatar, Here is cone 6 matt crystalline from Ted Secomb with firing schedule:
Lower fired matte crystal glaze 1220 c •Ferro frit 4064 or a lead bisilicatefrit 15 •Silica 16.5 •Kaolin 3.4 •Whiting 3 •Lithium Carbonate 6.1 •Potash Feldspar 23.5 •Barium carbonate 16 •Dense Zinc Oxide 16.5 •Titanium Dioxide 5
Firing Schedule forMid Range (cone 6)Matte Crystal glaze 1220 Centegrade Segment Ramp C Ramp F Temp C Temp F Hold 1 125/H 225/HR 1150 2102 0 2 50/HR 90/HR 1220 2228 10 min* 3 300 540/HR 1065 1949 1 Hour 4 300 540/HR 1040 1904 1 Hour 5 60 108/HR 1060 1940 1 Hour 6 7 * During segment 2 watch for your witness cone 6 to fall and your cone 7 to just begin to bend –once this has happened you can “skip step” to enable segment 3 to begin.
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