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AnnaM

Self Glazing Cone 04 Porcelain

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Ferro Frit 3110 is called "body frit" because it's commonly added to clays to flux them to Cone 6 or Cone 2 - which ever cone you prefer.

 

Ferro Frit 3110 is a high expansion frit, so you might prefer some other.  http://digitalfire.com/4sight/material/ferro_frit_3110_349.html

 

Perhaps 3195 which melts at the same temperature.  http://digitalfire.com/4sight/material/ferro_frit_3195_356.html

 

And if you want to add white plasticity to your porcelain, buy some VeeGum.  It's far more costly than common bentonite, but very white firing.   http://www.axner.com/bentonite-vee-gum-t.aspx

 

Like any artist, try new things!

I've got the results of 4 batch tests cooling down in the kiln as we speak! I'll post the photos tonight.

One thing I've learned in the last few days is that I will never take plasticity for granted again! I started feeling like I couldn't throw and had to mix up a few hundred grams that was only ball clay and Frit to prove to myself that I still could!

The whole reason that I wanted to try this was because my little kiln only gets up to Cone 03, and I need a body that will vitrify at that low temperature. The ball clay I've used is quite a greyish one and (in order to get a whiter clay body) was wondering whether adding Frit to my fine white earthenware clay would lower it's vitrification point? Does that sound like a silly idea? Is there any reason you couldn't muck around with a pre-mixed commercial clay?

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Norm, does Vee gum have another name down here in Australia? (Bentonite is quite cheap down here, by the way, only about $5 a kg at one of my suppliers and even cheaper if you buy in bulk!)

 

Do they both basically perform the same function? What sort of percentage in a clay body would be sufficient?

 

And when you say 4110 is an expanding body, what does that mean? Is it plausible to think that a glassy body could be made up of just frit, kaolin & veegum or bentonite?

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The results so far are encouraging, even the extreme experiments are interesting.

 

post-62155-0-71019900-1390912083_thumb.jpg

 

The last one of this lot was the 1:1 ball clay / frit mix just for curiosity's sake and because I was hanging out for some plasticity by this stage. Fired too hot to c03, next time will fire to 04. It was super good to to throw with :)  Lovely glossy surface despite the fact that it melted!

 

 

 

post-62155-0-29826700-1390912111_thumb.jpg

 

This one is 15 parts frit / 10 ball clay / 10 whiting.  More like a white stoneware as the whiting made it opaque. A bit more plastic but not much more and doesn't seem glassy at all.  Fired to c03.

 

 

post-62155-0-98968800-1390912136_thumb.jpg

This one was 1:1 frit and kaolin just to see what it would do. It cracks. Lovely and white though. Not self glazing. I'm assuming that's because the melting point of the kaolin is so high? Also an interesting lesson in what happens when you try to throw a substance with not a scrap of plasticity! It's like throwing butter. Fired to Cone 03.

 

 

post-62155-0-12257100-1390912190_thumb.jpg

 

This one also has no plasticity and was another bit of an extreme test just to see if it could be useful. I think it's good from a sculptural point of view to know what these combinations will do. This is 10 parts kaolin / 10 4110 frit / 3 whiting / .5 epsom salts ( I read somewhere that the plasticity can be increased by adding Epsom salts to the water, but I don't know whether it did add any plasticity really, not at that proportion anyway).

 

 

post-62155-0-26769100-1390912222_thumb.jpg

 

These ones were fired to c03, and although they flopped they have the most desirable colour. This composition was 10 kaolin / 25 ball clay / 10 whiting / 65 frit 3110.   It's a lovely very slightly creamy off white and is beautifully satiny, but I'll make up another batch tomorrow and only fire to 04 to see if it still has that lovely finish and doesn't flop.  I see what you mean Irene about the potential for using for sculpture, the possibilities are endless! When you hold the more open one to the light you can see that its translucent

 

post-62155-0-71487600-1390912245_thumb.jpg

 

This one was fired to Cone 04, it was the original 25 kaolin / 25 ball clay / 50 frit recipe. Not much plasticity, translucent, an off white colour and looks amber when light comes through it.  This recipe didn't become glossy or satiny on the surface (which is why I fired the next firing to c03).  Interesting though. I'm going to refire this one to c03 to see whether it goes glossy and stays up, or flops.

 

I'll get some bentonite tomorrow and mix some batches with it, plus mix and refire batch B & F at C04.  Its a great exercise, very steep learning curve!

post-62155-0-71019900-1390912083_thumb.jpg

post-62155-0-29826700-1390912111_thumb.jpg

post-62155-0-98968800-1390912136_thumb.jpg

post-62155-0-12257100-1390912190_thumb.jpg

post-62155-0-26769100-1390912222_thumb.jpg

post-62155-0-71487600-1390912245_thumb.jpg

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You'll soon understand why some porcelain makers fire their bowls in refractory "bowl setters" so the plastic bone china or porcelain, which can get plastic if fired to its full maturity cone, can lay down into the setter shape. 

 

A refractory cup-setter on the left.  The bone-china cup on the right sits on the cup-setter while being fired in the kiln, to retain its shape.  There is even a handle setter.

dencycup3.jpgdenbycup6.jpg

A porcelain which "self-glazes" is very likely to require this for larger pieces, as the reason for the glassy glaze on the surface is that entire body is the same, glassy and plastic.

 

Most factories use a less fluxed-porcelain which retains its shape better, so does not require plate setters, but these porcelains require glaze. http://science.howstuffworks.com/innovation/51-how-fine-china-is-made-video.htm

www.youtube.com/watch?v=bpaFi-kIlNU

 

Ceramic Arts Daily member Chris Campbell firing porcelain bowls in bowl setters to help them retain their shape.

gallery_18533_680_112219.jpg

 

 

The results so far are encouraging, even the extreme experiments are interesting.

 

attachicon.gifBatch F.jpg

 

The last one of this lot was the 1:1 ball clay / frit mix just for curiosity's sake and because I was hanging out for some plasticity by this stage. Fired too hot to c03, next time will fire to 04. It was super good to to throw with :)  Lovely glossy surface despite the fact that it melted!

 

 

 

attachicon.gifBatch E.jpg

 

This one is 15 parts frit / 10 ball clay / 10 whiting.  More like a white stoneware as the whiting made it opaque. A bit more plastic but not much more and doesn't seem glassy at all.  Fired to c03.

 

 

attachicon.gifBatch D.jpg

This one was 1:1 frit and kaolin just to see what it would do. It cracks. Lovely and white though. Not self glazing. I'm assuming that's because the melting point of the kaolin is so high? Also an interesting lesson in what happens when you try to throw a substance with not a scrap of plasticity! It's like throwing butter. Fired to Cone 03.

 

 

attachicon.gifBatch C.jpg

 

This one also has no plasticity and was another bit of an extreme test just to see if it could be useful. I think it's good from a sculptural point of view to know what these combinations will do. This is 10 parts kaolin / 10 4110 frit / 3 whiting / .5 epsom salts ( I read somewhere that the plasticity can be increased by adding Epsom salts to the water, but I don't know whether it did add any plasticity really, not at that proportion anyway).

 

 

attachicon.gifBatch B.jpg

 

These ones were fired to c03, and although they flopped they have the most desirable colour. This composition was 10 kaolin / 25 ball clay / 10 whiting / 65 frit 3110.   It's a lovely very slightly creamy off white and is beautifully satiny, but I'll make up another batch tomorrow and only fire to 04 to see if it still has that lovely finish and doesn't flop.  I see what you mean Irene about the potential for using for sculpture, the possibilities are endless! When you hold the more open one to the light you can see that its translucent

 

attachicon.gifBatch A.jpg

 

This one was fired to Cone 04, it was the original 25 kaolin / 25 ball clay / 50 frit recipe. Not much plasticity, translucent, an off white colour and looks amber when light comes through it.  This recipe didn't become glossy or satiny on the surface (which is why I fired the next firing to c03).  Interesting though. I'm going to refire this one to c03 to see whether it goes glossy and stays up, or flops.

 

I'll get some bentonite tomorrow and mix some batches with it, plus mix and refire batch B & F at C04.  Its a great exercise, very steep learning curve!

 

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I don't mind glazing as well, I just really want a clay body that is vitrified at lower temps, so I don't have to do my glaze firings away from home! Makes it difficult having a kiln that only reaches 1100°!

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I always did like experimenting with self glazing clay bodies when I was in college.  really any clay body can become self glazing ... it really just comes down to finding that point of fluxing a clay body to where it still holds it shape with in a cone or two higher than you fire but the surface flux melts at the cone you fire to or a little under.  I had one I called a volcanic clay which I used silicon carbide in with high flux on an iron-ish rich clay body ... it fired to cone 10 and would sort of form a bubbled skin looking like course rock for some of my sculptures.  Mind you, it still had warping and distortion in thin areas because of the self fluxing, so that had to be overcome with thickness. 

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Veegum in Australia?  What you want is any white-firing type of calcium-bentonite or montmorillonite or smectite or fullers earth or hectorite.  These are all volcanic ash which have been decomposed over millions of years.  Most bentonites contain too much iron, so fire off-white.  Some off-white bentonites can be added up to 5% to a white body without affecting the final whiteness of the ware.  Some unwashed bentonites come with soluble salts which can be countered with 1/3% barium carbonate.

 

The whiteness comes from selecting white sections of the ore rock.  Veegum is a brand name of one type of white firing bentonite made by Vanderbilt industries in the US.  Macaloid is a brand name popular in the UK.  I think both are listed in ceramic materials in Australia -

 

Ask your Australian supplier if their Trugel 100 Bentonite is white firing.  It seems the most common type available there.

 

Norm, does Vee gum have another name down here in Australia? (Bentonite is quite cheap down here, by the way, only about $5 a kg at one of my suppliers and even cheaper if you buy in bulk!)

Do they both basically perform the same function? What sort of percentage in a clay body would be sufficient?

And when you say 4110 is an expanding body, what does that mean? Is it plausible to think that a glassy body could be made up of just frit, kaolin & veegum or bentonite?

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Really good read all of this. Enjoyed reading your posts especially Norm.

 

I remember reading something about a self glazing clay that while it was drying it had some water soluble flux that was brought up to the surface. This then went onto turn the outer layer of clay into a glaze.

 

Have I just been confused in my reading or is this a different technique? This way seems to be making a clay that is 100% glaze/clay hybrid.

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No you're not mistaken. I have come across some recipes that have some types of salts in them that come to the surface as the greenware is drying. I'll see if I can find them again for you ;)

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Many of the soluble salts which migrate to the surface are fluxes at the right temperature with the right materials, but they more often create a white surface called scumming.

 

Really good read all of this. Enjoyed reading your posts especially Norm.

 

I remember reading something about a self glazing clay that while it was drying it had some water soluble flux that was brought up to the surface. This then went onto turn the outer layer of clay into a glaze.

 

Have I just been confused in my reading or is this a different technique? This way seems to be making a clay that is 100% glaze/clay hybrid.

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Hi Anna

 

Just checked in again and noticed you are an Aussie girl....all good, I live in Sydney.

 

Checking back over my notes the whitest china clay I used for the Cone 4 body was Eckalite1, the warm creamy colour was from Clay Ceram.   I did use Frit 4064 (lead, no longer available)  and Frit 4110 (alkaline). I only used the regular bentonite the uni had. Though I've heard about Macaloid and Veegum the 3 catalogues I have from NSW Pottery Supplies, Walkers Ceramics and Keanes Ceramics do not mention different types of bentonite.....I just accepted the ivory white that Eckalite made and the cream from the Clay Ceram..... I love bonechina's whiteness so if you find a way to make it really white let me know!

 

Your soft shapes are SO sweet!!.....I don't think all pottery needs be rigidly round or 'perfect'......that is the beauty of the pottery from so many other cultures who are not slaves to the 'mechanical' roundness of an electric wheel......I have an electric wheel which finds more use as a glaze mixing tool these days!!! I use a truely beautifully made kick wheel which allows individuality and variations in a bowl's shape depending on my kick rhythm....have come to admire the 'wonky pot' after watching Japanese master Ryoji Koei demonstrate at uni many years ago.....

 

.......so find the soft shapes and ivory white of your Cone 4 Porcelain experiments lovely......show us more when you can.

 

Irene

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This one has only a really small amount of Bentonite, about 5%. It doesn't really seem to make much difference to the colour, it definitely has a slight warmth to it which I like better than the stark white. oh and this one was only fired to the very bottom range of cone 04 so it has that almost metallic type sheen.

post-62155-0-33260600-1391778925_thumb.jpg

post-62155-0-33260600-1391778925_thumb.jpg

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Really good read all of this. Enjoyed reading your posts especially Norm.

 

I remember reading something about a self glazing clay that while it was drying it had some water soluble flux that was brought up to the surface. This then went onto turn the outer layer of clay into a glaze.

 

Have I just been confused in my reading or is this a different technique? This way seems to be making a clay that is 100% glaze/clay hybrid.

 

 

The  'soluble salts rising to the surface during drying' sounds like this is an Egyptian paste recipie you may be thinking of, which is a low firing self glazing body (often coloured turquoise though white and other colours may be had) the salts form as the 'glaze' layer over the form.  This body is used for smaller decorative pieces rather than functional ware.

 

Weblinks are:

http://ceramicartsdaily.org/wp-content/uploads/2010/06/egyptianpaste.pdf

http://www.ceramicstoday.com/articles/092501.htm

http://www.amywallerpottery.com/faience

 

 

Anna's query is the 100% clay/glaze hybrid body.

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Hi,

 

I just came across this post and thought I would throw my 2 cents in. I went to a workshop a couple of years ago where a cone 04 translucent porcelain body was mentioned in passing by Kurt Weiser. The recipe is 50% NewZealand China Clay, 50% Ferro Frit 3195 and 2% VeeGum to increase plasticity. I have used it and it is extrodinarliy translucent and it totally vitrifies and self glazes. I have experimented a little with Mason stains as well to add a little colour and they work really well. Mix a little stain and a little of the frit and you have a nice way to add some colour.

 

I have found that although the VeeGum is supposed to be relatively colourless, it does add a pinkish tint.

I have used this to throw as well has to make hand formed beads. I found that if I bury the beads in a bisqued pot full of alumina hydrate, they will not stick together and come out quite matte but they have a lovely silky feeling. To remove the rough alumina that might stick to them, just pour the beads into a plastic bag, seal it and agitate with your hands, they will come out all nicely pollished.

For throwing, I find it quite soft and buttery, it hardens really nicely, not too fragile in the green state. When firing, I place the pots on a layer of alumina and then just sand of any alumina residue afterwards.

Here is a link to some images of some small pieces I made with it.

http://thecrackedpotter.blogspot.ca/2013/01/well-it-is-january-3rd-and-i-have-not.html

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Beautiful!! Do you find the shrinkage rate is enormous? And it looks like yours is a bit easier to trim than the recipes I've been making. Did you trim at Leatherhard or when it was a bit drier? Mine seems to need to be a bit harder as they've all had a really fudgey/nougat type consistency at Leatherhard!

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Shrinkage is huge, but I have not done any tests to give you an accurate percentage. I would guestimte 25%.

As for trimming, yes, slightly drier workes best. I had previously invested in a tungsten carbide trim tool and it will trim bone dry much easier (even regular bisque for that matter).

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The latest nearing-success story:

 

Cullet              65

Kaolin             10

clay ceram      25

whiting            20

molochite       15

bentonite          1

 

Its very white, strong and translucent. I fired it to cone 05. The clay ceram (or star cast as its also known here) is the same as your tennessee ball call I think?  Its a very plastic, white firing ball clay. 

 

It came out nice and plastic, fine to throw and a bit easier to trim than some of the recipes.

 

post-62155-0-77550100-1396851564_thumb.jpg

post-62155-0-77550100-1396851564_thumb.jpg

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cone 04 translucent porcelain body was mentioned in passing by Kurt Weiser. The recipe is 50% NewZealand China Clay, 50% Ferro Frit 3195 and 2% VeeGum to increase plasticity..

 

 

Crackpot,  

 

Hi, I'm just wondering where you got the New Zealand China Clay? I noticed you live in Canada so I'm guessing you didn't get it in New Zealand. I live in California and was hoping to get it online.

 

Thanks,

Sprinf

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Mark, thanks for the tip. I never check people's post history. I saw it was from 2014, but I know people always seem to come and go and then come back to this forum. Well, at least that's the case with me :P

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This may be of interest to some - recently on Digitalfire, Tony Hansen published a recipe for what he is calling Low Fire Polar Ice. Here is the recipe and the link: 

 

Cone 03 

 

Material                              Amount            Units    

New Zealand Kaolin          10.0                 50BG

Ferro Frit 3110                   6.0                   50BG

Silica                                  4.0                   50BG

VeeGum T                          30.0LB

Mason 6336 Blue Stain     250.0GM

 

https://digitalfire.com/4sight/recipes/zero3_porcelain_experimental_133.html

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