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Bone China ?


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#1 Corinda Genev

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Posted 21 June 2013 - 06:58 PM

Hi, I am currently making porcelain jewelry. I have been using P300 - fired at cone 7, but I not only find that it comes out gritty, but not as white as I would like.

I am interested in looking into bone china for making my jewelry, but have been having trouble finding information on it - is it a clay that you can buy, or do you need to make it yourself?

I live in Vancouver btw, so unless I order online, my clay choices are limited.

#2 TJR

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Posted 21 June 2013 - 10:21 PM

Corinda;
I have used P580, which is a porcelain from Plainsman in Medicine Hat, Alberta. I think there is also a clay supplier in Seattle,which is close to you.
Bone China is a type of clay developed by Josiah Wedgewood in Stoke on Trent.The clay contains bone ash which is calcium sulphate. Come from ground up cow bones. Stinks like something awful when wet. Actually, come to think of it, it smells like ground up cow bones.
Bone Ash was developed to mimic porcelain. It was bisgued to the maturing temperature of the clay, say cone 7, then the glazes were applied at a much lower temperature. It is not a clay that you can buy, but is an industrial manufacturing technique.
I am from Winnipeg.Welcome to the forum.
TJR.

#3 Mark C.

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Posted 21 June 2013 - 11:38 PM

There is ceramic supplier called greenbarn in Vancouver BC. Forget about bone china.
I'm sure that they have a cone 6 white porcelain body that will be very white.
Mark
Mark Cortright
www.liscomhillpottery.com

#4 Wyndham

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Posted 22 June 2013 - 10:41 AM

Awhile back, several years in fact , I found several recipes for bone china. I used synthetic bone ash(no smell) clay and Cornwall stone.

Here's a link to some info

http://billandlizhun...Bone_China.html

I didn't find it special enough to do more than a few test but you might want to carry it further.
Wyndham

#5 TJR

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Posted 22 June 2013 - 06:37 PM

Awhile back, several years in fact , I found several recipes for bone china. I used synthetic bone ash(no smell) clay and Cornwall stone.

Here's a link to some info

http://billandlizhun...Bone_China.html

I didn't find it special enough to do more than a few test but you might want to carry it further.
Wyndham


I use my bone ash in a white glaze that I really like. It is a recipe I got while in Australia. It is a white that is not matt, and has a bit of a sheen to it due to the bone ash. I must still have the old stuff as it stinks when I stir it up. Not a bad smell, but I know that it's there.Like Mark said, and I was trying to point this out in my previous post, bone china is a firing technique. Use a porcelain body.
TJR.

#6 Mudslinger Ceramics

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Posted 23 June 2013 - 04:18 AM

Hi Corinda

Below are the 2 recipies I used at college given to me by my lecturer but they were not his original formulas. Formulas are given in books 'Slipcasting' by English potter Sasha Wardell and 'Contemporary Porcelain' by Peter Lane when discussing the work of Australian potter Sandra Black

Synthethic bone ash 45
Cornish stone 30
China clay 25

OR

Synthetic bone ash 45
China clay 30
Potash feldspar 25

to make it into a casting slip add 0.4% Dispex; to attempt a plastic body add 3% bentonite: I have used real bone ash and have not had the smell but I choose synthetic bone ash for it's chemical consistency batch to batch

bone china is an EXTREMELY finicky clay body to work with which is why it's almost always slipcast-
.....it's a very 'short' body (think crumbly cookie dough) and attempts to increase the clay content to gain better plasticity change the colour from a stark 'cold' white towards creamy off-white
.....it's frustratingly delicate as greenware and will fire with an appalling 'memory': honestly, a simple knock without any damage will still result in warping
.....it'requires exact firing to 1250C, any higher and it slumps miserably
.....it can have a very high failure rate/ kiln load

but when it works.....it is ABSOLUTE MAGIC!.....which is why I continue to work with it even through the howls of frustration! Walker Ceramics in Melbourne Australia have just recommenced manufacture.

In your post you do not mention your forming and/or decorating techniques, so my suggestion would be that unless you require or 'just love and must have' the stark, white, stone like look of bone china then look into the super white porcelains available, they are easier to work with.

There is a current discussion thread on Cone 6 Cool Ice porcelain and the comparison of various super white porcelain bodies found in the US, you may find what you're looking for there.

Good luck whatever you choose.

Irene

Mudslinger Ceramics :   www.mudslingerceramics.net

 

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It will stick with you and show up for better or for worse in spite of all you or anyone else can do.'

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#7 Corinda Genev

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Posted 23 June 2013 - 06:34 AM

Thank you everyone for all of the information. I think that I might experiment a little with making my own china clay - so many recipes to choose from though.
Irene, about my methods, I usually use a press molds that I've made or less hand form.

Cheers

#8 Nancy S.

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Posted 23 June 2013 - 09:34 AM

Corinda;
I have used P580, which is a porcelain from Plainsman in Medicine Hat, Alberta. I think there is also a clay supplier in Seattle,which is close to you.
Bone China is a type of clay developed by Josiah Wedgewood in Stoke on Trent.The clay contains bone ash which is calcium sulphate. Come from ground up cow bones. Stinks like something awful when wet. Actually, come to think of it, it smells like ground up cow bones.
Bone Ash was developed to mimic porcelain. It was bisgued to the maturing temperature of the clay, say cone 7, then the glazes were applied at a much lower temperature. It is not a clay that you can buy, but is an industrial manufacturing technique.
I am from Winnipeg.Welcome to the forum.
TJR.


According to http://en.wikipedia....e_china#History -- it was Josiah Spode, though he got the idea from Thomas Frye. Wedgewood popularized it.

Pottery - including the potter's wheel - dates back to the Sumerians. I'm betting someone before Frye & Spode put crushed bones in clay! :)

I remember ages ago seeing a thing on tv with a woman who put a bone china teacup on the floor and then STOOD upon it. The cup held her weight - demonstrating bone china's strength. I'm still not sure if that was legit or not...




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