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#1 Avaviel

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Posted 04 December 2012 - 01:43 AM

I hope this is ok: I'd like to make a thread about my own searches in glaze and clay formulating. The idea is that this would be a helpful resource, based on what I've read and the help I've recieved from my art teachers (ceramics or not – for example, my printmaking teacher is quite wise in areas that touch on clay.) I encourage anyone to comment about the stuff I post here. I'll most likely edit this top post as time goes on to add glazes, clay mixes, edit for content, edit for format, and add photos of the glazes.


____________________________________
Porcelain, cone 10.

Tile#4* 24
EPK 16
OM4 Ball Clay 20
Silica (Flint) 18
Custer 22

*When I first mixed this, it was Diamond. For the main thing, my teacher suggested I get Tile#4.
____________________________________
I've decided that I absolutely love porcelain, and that throwing with it is wonderful. I've read a bit on formulating a porcelain clay here. Based upon a formulia I found online, and my teacher's insight, here is the clay that I'll be making next semester. I'm going to age it too; I'll be buying it as I'm able and will add some vinegar and other aging agents. If you guys have any thoughts on how this mix will be this next semester, I'm eagerly awaiting! If I can make helpful changes before I start, that will be nice. I may mix and age a portion of the Tile#4 in case I want to make any adjustments: Then I can add the dry materials with a new ratio.



____________________________________
Midori(N), cone 10 (Japanese for green)

Custer 24
Silica (Flint) 19
Wollastonite 17
EPK 19
Crimson 5
Gersley Borate 4
Volcanic Ash 12
Mag Carb 4.5

Posted Image
Ceramics by avaviel, on Flickr
____________________________________
This is a glaze that is like a green clear, it crazes. This is the new formula that my teacher came up with, he rearranged a few things and made it shorter. (He described it as rearanging the parts of the glaze, consolidating the fluxes and glass makers.) I'll post a photo of the glaze bowl that this is on, I think I can live with the crazing. Typically, crazing have the cracks going in many directions... but on one of my bowls with a flat edge about a centimeter across, the cracks are about a cintemeter apart, all facing to the center. It's rather stunning: and I can say that because it wasn't my conscious choice to have it to do that! This is also the glaze that taught me that making glazes is really fun.



____________________________________
Metal Glaze Test, cone whatever... but I'll do it in 10.

EPK 4
Bone Ash 10
Talc 8
Iron Oxide 10
Silica (Flint) 20
Feldspar!!!!!!!11111!!1eleveny: 48
____________________________________
Here is the joke, regarding the feldspar: I saw this glaze in an old magazine. (I'll get the edition number later.) I showed it to him: It was a glaze for a predominately iron matte glaze. He read through the ingredients, saying that they made clear sense until he got to the feldspar. Which feldspar was the question. To that end: Let the glaze testing commence!

In our art dept's clay area, we have four feldspars: Custer, F-4 (Soda), Sopdome, and Neph Sy. The idea is to mix the glaze around 300 grams four times, each with the full percent of the separate feldspars that we have in stock. Then, do a bunch of glaze tests to try and find something that we like. (We're not trying to duplicate the magazine, that would be futile and silly.) So there will be a bunch of test tiles with C+S+NS and so on.


Interesting links:
This is an older post about Lucy Rei's glazes. I plan to look up the magazine and post the results of the tests. Hopefully they have some of her cratering glazes.

http://ceramicartsda...ucy-rei-glazes/

Hey, look. Iron!
http://ceramicartsda...hnofileiron.pdf



#2 TJR

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Posted 04 December 2012 - 02:46 PM

I hope this is ok: I'd like to make a thread about my own searches in glaze and clay formulating. The idea is that this would be a helpful resource, based on what I've read and the help I've recieved from my art teachers (ceramics or not – for example, my printmaking teacher is quite wise in areas that touch on clay.) I encourage anyone to comment about the stuff I post here. I'll most likely edit this top post as time goes on to add glazes, clay mixes, edit for content, edit for format, and add photos of the glazes.


____________________________________
Porcelain, cone 10.

Tile#4* 24
EPK 16
OM4 Ball Clay 20
Silica (Flint) 18
Custer 22

*When I first mixed this, it was Diamond. For the main thing, my teacher suggested I get Tile#4.
____________________________________
I've decided that I absolutely love porcelain, and that throwing with it is wonderful. I've read a bit on formulating a porcelain clay here. Based upon a formulia I found online, and my teacher's insight, here is the clay that I'll be making next semester. I'm going to age it too; I'll be buying it as I'm able and will add some vinegar and other aging agents. If you guys have any thoughts on how this mix will be this next semester, I'm eagerly awaiting! If I can make helpful changes before I start, that will be nice. I may mix and age a portion of the Tile#4 in case I want to make any adjustments: Then I can add the dry materials with a new ratio.



____________________________________
Midori, cone 10 (Japanese for green)

Custer 24
Silica (Flint) 19
Wollastonite 17
EPK 19
Crimson 5
Gersley Borate 4
Volcanic Ash 12
Mag Carb 4.5
____________________________________
This is a glaze that is like a green clear, it crazes. This is the new formula that my teacher came up with, he rearranged a few things and made it shorter. (He described it as rearanging the parts of the glaze, consolidating the fluxes and glass makers.) I'll post a photo of the glaze bowl that this is on, I think I can live with the crazing. Typically, crazing have the cracks going in many directions... but on one of my bowls with a flat edge about a centimeter across, the cracks are about a cintemeter apart, all facing to the center. It's rather stunning: and I can say that because it wasn't my conscious choice to have it to do that! This is also the glaze that taught me that making glazes is really fun.



____________________________________
Metal Glaze Test, cone whatever... but I'll do it in 10.

EPK 4
Bone Ash 10
Talc 8
Iron Oxide 10
Silica (Flint) 20
Feldspar!!!!!!!11111!!1eleveny: 48
____________________________________
Here is the joke, regarding the feldspar: I saw this glaze in an old magazine. (I'll get the edition number later.) I showed it to him: It was a glaze for a predominately iron matte glaze. He read through the ingredients, saying that they made clear sense until he got to the feldspar. Which feldspar was the question. To that end: Let the glaze testing commence!

In our art dept's clay area, we have four feldspars: Custer, F-4 (Soda), Sopdome, and Neph Sy. The idea is to mix the glaze around 300 grams four times, each with the full percent of the separate feldspars that we have in stock. Then, do a bunch of glaze tests to try and find something that we like. (We're not trying to duplicate the magazine, that would be futile and silly.) So there will be a bunch of test tiles with C+S+NS and so on.


Interesting links:
This is an older post about Lucy Rei's glazes. I plan to look up the magazine and post the results of the tests. Hopefully they have some of her cratering glazes.

http://ceramicartsda...ucy-rei-glazes/

Hey, look. Iron!
http://ceramicartsda...hnofileiron.pdf


Avaviel;
O.K.I decided to help you out with one of your glazes. The first one I didn't want to take on as I don't know the material crimsom. I took a look at your glaze and decided to convert it to a standard percentage form so you know what you are looking at.Most glazes toal to 100, so that you can look at it as a percent. AFTER all the materials, THEN you add the oxides. You have an awful lot of iron in there to create a gun metal look.
1. I removed the iron temporarily.
2. I totalled the glaze materials sans iron.
3. Your total is 90
4. You devide each material by 90 to get a percentage of 100
5. Here goes;
EPK 4
bone ash 11
talc 9
Flint 22
Spar 53
Total 99
6. To make it 100 I just added one to talc to make it 10

7. Now that you have your base glaze without colourants, you can make a line blend with iron
8. Mix up one 300 gram batch. Add 3 grams of iron which would be 1%.Make a test tile of that.
9. Add another 1% or 3 grams to the same cup of glaze. Now you have 2% iron.
10.Do 3%, 4%, 5%,6% etc to the same cup up to 10%
11. In another cup, try black iron as a line blend
12. Burnt umber
13.Albany slip
14. Yellow ochre.

I hope this makes sense. It's easier to show than write.
Good luck. I love glaze tests.
Tom Roberts

#3 Avaviel

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Posted 12 December 2012 - 05:32 PM

Thanks for the help!

With the metallic glaze, I'm aiming to have a gun metal type feel, as I've noticed they transmit much less heat when on cups. For this test, I did something like a quad-axial, and the variable was the EPK. In the future, I'll give your test a try when I've seen the results of this cone 10 kiln. I need to start doing tests that vary a majority of the ingredients.

Does it really matter if a glaze adds up to 100? Right now my thought is that it does not matter for internal testing, just making tests where the ingredients are 'parts', and the 'part' is one gram. (10 parts of x is 10 grams of x.) Then, when the glaze is finalized, make it into percents.

I'm also testing amounts of Silica carbonate in slips/glazes to produce cratering. I think at some point I'd like to formulate a soft cratering gun metal glaze. Some day I'll be able to intuitively change glazes! I look forward to knowing the materials that much.

I'll post the results of the glaze testing when the kiln cools.

#4 neilestrick

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Posted 12 December 2012 - 05:56 PM

Good stuff. Hope you're having a lot of fun with this. The only comment I have is that I wouldn't call your clay body porcelain. In my opinion, if it's got ball clay in it then it's a white stoneware. In reduction it will not be as white as a true grolleg porcelain. Much of what makes porcelain so unique in the way it feels is the lack of plasticity due to the lack of plastic clays like ball clay.

Neil Estrick
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L&L Kilns Distributor
Owner, Neil Estrick Gallery, LLC
www.neilestrickgallery.com

neil@neilestrickgallery.com


#5 Marcia Selsor

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Posted 12 December 2012 - 07:03 PM

Thanks for the help!

With the metallic glaze, I'm aiming to have a gun metal type feel, as I've noticed they transmit much less heat when on cups. For this test, I did something like a quad-axial, and the variable was the EPK. In the future, I'll give your test a try when I've seen the results of this cone 10 kiln. I need to start doing tests that vary a majority of the ingredients.

Does it <i>really</i> matter if a glaze adds up to 100? Right now my thought is that it does not matter for internal testing, just making tests where the ingredients are 'parts', and the 'part' is one gram. (10 parts of x is 10 grams of x.) Then, when the glaze is finalized, make it into percents.

I'm also testing amounts of Silica carbonate in slips/glazes to produce cratering. I think at some point I'd like to formulate a soft cratering gun metal glaze. Some day I'll be able to intuitively change glazes! I look forward to knowing the materials that much.

I'll post the results of the glaze testing when the kiln cools.


Having your glaze total 100 gives you a good grasp of percentages at a glance if you go to compare one with other glazes. It also makes for easy testing on colorants.
Marcia

#6 Avaviel

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Posted 12 December 2012 - 08:57 PM

Good stuff. Hope you're having a lot of fun with this. The only comment I have is that I wouldn't call your clay body porcelain. In my opinion, if it's got ball clay in it then it's a white stoneware. In reduction it will not be as white as a true grolleg porcelain. Much of what makes porcelain so unique in the way it feels is the lack of plasticity due to the lack of plastic clays like ball clay.


Ah, it was my professor who modified this recipe based another one. I've really liked working with it, when I made a smaller batch. In the future, I'll formulate a porcelain based on this website: Formulating a Porcelain by DigitalFire

I ALSO found that I don't hate stoneware as I previously thought. I sifted the sand and grog from it, and really liked it without that extra stuff.


<snip></snip>


Having your glaze total 100 gives you a good grasp of percentages at a glance if you go to compare one with other glazes. It also makes for easy testing on colorants.
Marcia


Ah, that's a good point. I'm reading a book right now called The Ceramic Spectrum by Robin Hopper, but I'm not quite to that part yet. The next kiln fire I'll do some colorant tests.

#7 Avaviel

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Posted 14 December 2012 - 11:23 PM

I'm kicking myself because I left the photo of the metallic glaze test at home. However, I did upload the photos of the 'new' Midori glaze. Now it's looking like a green celadon, before the re-design it looked like a crackling green glass.

'New' Midori
Posted Image

'old' Midori
Posted Image

My plan is to do a line blend between the two, as the simplification that my professor did greatly changed the look... I don't mind the new look, but I'd like to see what happens in the blends. I have a feeling that through the line blends I'll start to get a feel about controlling the crackle.

Midori old
I've re-distributed everything to add up to 100%.
Custer 18.2
Flint 16
EPK 16.8
Crimson 4.6
Gersley Borate 3.6
Bentonite 1
Whiting 7.4
Neph Sy 8.2
Volcanic Ash 13
Mag Carb 3.2



TJR, after the glaze tests I've found a version of that metallic glaze that I like – I'll start calling it Iron #5 for now. (It was the fifth out of sixteen tests.) It has the red, but it also has a nice black accent that shows up on bumpy areas. I'll edit the photo in later, but for now here is the recipe.

IRON #5
EPK 4.4
Bone Ash 11
Talc 8.8
Flint 22
Custer 18
F-4 27
Spodumene 8.8

Iron was removed, and Red Iron will be added in 1% intervals as suggested. I'll also try the other colorants. I'll have to make taller test tiles, as the glaze runs. That's ok, as I also want to design functional wear that will suit the glaze.

It's nice that Christmas is coming up... but I may go crazy, as I won't have access to 'the lab' and the wheel!

#8 Ben

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Posted 20 December 2012 - 08:23 AM

Does it really matter if a glaze adds up to 100? Right now my thought is that it does not matter for internal testing, just making tests where the ingredients are 'parts', and the 'part' is one gram. (10 parts of x is 10 grams of x.) Then, when the glaze is finalized, make it into percents.



Like Marcia said, it just makes things easier to compare with other glazes.

I'd like to make a few suggestions.
1. Buy and learn how to use glaze software. my favorite is glazemaster and get the mastering cone 6 glazes book. After doing calculations for years by hand I have to say that this is by far the highest value per dollar expenditure I have ever made. Saves more time and gives access to more information than any other ceramic related tool I own.
2. Learn how to test coefficient of expansion by using a test glaze series ( several glazes with various COE values to test a relative COE of your test clay body... all detailed in the book)
3. Learn how to test absorption in clay bodies.
4. Find an article called "Body Building for Potters" from studio potter magazine.
5. when writing glaze recipes organize them so that the base ingredients add to 100. Consider the colorants separately.

The glaze software will take care of the math for you and you can convert recipes into 100 gram batches with 2 mouse clicks.

If you want to get even deeper you can make a rig to test breakage strength of test bars but I wouldn't worry about that until you have a good grasp upon coe and absorption testing.

Ben




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