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why are you thinking of doing this?   

if you fire stoneware to less than the temperature and heat needed to fully fuse the clay particles together, you will have a clay that is not strong enough to use.   if it is mixed with earthenware that does not change.

why do you even think of this?

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4 hours ago, Jools said:

Hi there,

I wonder is it possible to mix a stoneware clay and a earthenware clay together  and fire to come 06.

Any tips / advice greatly appreciated ,

Julia 

I'm ignorant of most of the sometimes confusing details but while it's possible to mix glazes and lower the firing range, clay is a different matter all together.

Edited by C.Banks
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Our shop reclaim in school was a hodgepodge of heaven only knew what. The practice at the time was to homogenize it thoroughly in a Soldner mixer and add a bag of fireclay to ensure nothing would turn into slag at cone ten. So yes it is possible to mix clay bodies and alter their maturation point.  Firing it to lower temperatures rather than higher will have fewer risks of it turning into a brown volcanic looking lump, so it's worth a try. Because it was a larger teaching studio, there was access to larger clay mixing equipment. In a lower tech studio, you can either cut and slam the two clay bodies together 50 times or so, or you can slurry mix them both together to the consistency of smooth pudding, and dry it out on plaster or by using some other de-watering method. You then have essentially a new clay body that you have to test for porosity levels, and if you want to use it for dinnerware, it would be a good idea to find out where the new top maturation point is. If you're using this mix for sculptural or other non-dinnerware uses,  the new maturation point and porosity may be of a lesser concern. 

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It's definitely possible, all it takes is some muscle and wedging. Not sure what the goal is though.

With ceramic materials, if you mix a material that melts at 1000 degrees and a material that melts at 500 degrees in equal parts, the resulting mixture will melt at 750 degrees.  Not that you'd normally want to melt clay.  

Edited by liambesaw
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If you're mixing store bought clay, as a rule of mine, and the key to why people hate wedging, is because it is beaver structure near impossible to wedge it on any surface and have it stay wet enough to remain ergohelpful!

It's simply because no one wants to pay to ship excess water.

They posted an "add water to the bag trick" on another thread that you can probably use to keep it more comfortable.

Too, as far as levels of energy goes, any bit of energy lost to a rocking wedging table is being replaced by you. Keep it steady.

I negated this problem by wedging in the air, just in the hands. Odd that when you slap two handfuls of clay together, you have a human heart shape. Kinda creates a... creation story.

Anyway that keeps it wet enough to mix a bowl/mug worth of clay rather quick.

Slap em together, then rip it apart like you're ringing out a dishrag and slap em together again.  Use your knees to smash em together. Excersize bonus!

Just wash the initial dried clay off your hands to keep it from further drying out the clay. After while, it won't leave anymore on your hands.

I recently mixed Standard 101 (cone 9) 900g with a local earthenware 300g and fired it to cone 6 and it tested Vitreous. 

Been mixing Standard 547 (cone 6) and 205 (cone 10). 547 and Amaco 46 (cone 10), 547 and 101, In 50/50 and it's Vitreous at cone 8.

A recipe I've been making calls for 20% Red Earthenware, it fires to Cone 10. I've yet to fire them all the way to cone 10. Trying 2 types of local Earthenware. One is near Vitreous at cone 8. Closer at 9. 

I think you'll be mighty porous yet at 06. Unless you're using a 012 earthenware at like 75% and just using the stoneware to stretch it.

Sorce

 

 

 

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14 hours ago, Callie Beller Diesel said:

Our shop reclaim in school was a hodgepodge of heaven only knew what. The practice at the time was to homogenize it thoroughly in a Soldner mixer and add a bag of fireclay to ensure nothing would turn into slag at cone ten. So yes it is possible to mix clay bodies and alter their maturation point.  Firing it to lower temperatures rather than higher will have fewer risks of it turning into a brown volcanic looking lump, so it's worth a try. Because it was a larger teaching studio, there was access to larger clay mixing equipment. In a lower tech studio, you can either cut and slam the two clay bodies together 50 times or so, or you can slurry mix them both together to the consistency of smooth pudding, and dry it out on plaster or by using some other de-watering method. You then have essentially a new clay body that you have to test for porosity levels, and if you want to use it for dinnerware, it would be a good idea to find out where the new top maturation point is. If you're using this mix for sculptural or other non-dinnerware uses,  the new maturation point and porosity may be of a lesser concern. 

Thanks so much for your detailed reply.  I have barrels  full of a white earthenware clay that is not strong enough for the wheel. I also have a lot of nice stoneware . I wouldn't be using for any tableware . So thanks for this info.

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18 hours ago, oldlady said:

why are you thinking of doing this?   

if you fire stoneware to less than the temperature and heat needed to fully fuse the clay particles together, you will have a clay that is not strong enough to use.   if it is mixed with earthenware that does not change.

why do you even think of this?

Thanks, because I want a clay strong enough for throwing and white enough for the glazes I use. I'm not using for any tableware. I have barrels full of both clays soaking and wanted to avoid having to buy more.

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14 hours ago, liambesaw said:

It's definitely possible, all it takes is some muscle and wedging. Not sure what the goal is though.

With ceramic materials, if you mix a material that melts at 1000 degrees and a material that melts at 500 degrees in equal parts, the resulting mixture will melt at 750 degrees.  Not that you'd normally want to melt clay.  

Thanks for replying, I have lots or recycled clay soaking and could easily mix together. I'm trying to avoid buying more clay and want a strong white wheel throwing clay. I'll give it a go and see what happens !

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8 hours ago, Sorcery said:

If you're mixing store bought clay, as a rule of mine, and the key to why people hate wedging, is because it is beaver structure near impossible to wedge it on any surface and have it stay wet enough to remain ergohelpful!

It's simply because no one wants to pay to ship excess water.

They posted an "add water to the bag trick" on another thread that you can probably use to keep it more comfortable.

Too, as far as levels of energy goes, any bit of energy lost to a rocking wedging table is being replaced by you. Keep it steady.

I negated this problem by wedging in the air, just in the hands. Odd that when you slap two handfuls of clay together, you have a human heart shape. Kinda creates a... creation story.

Anyway that keeps it wet enough to mix a bowl/mug worth of clay rather quick.

Slap em together, then rip it apart like you're ringing out a dishrag and slap em together again.  Use your knees to smash em together. Excersize bonus!

Just wash the initial dried clay off your hands to keep it from further drying out the clay. After while, it won't leave anymore on your hands.

I recently mixed Standard 101 (cone 9) 900g with a local earthenware 300g and fired it to cone 6 and it tested Vitreous. 

Been mixing Standard 547 (cone 6) and 205 (cone 10). 547 and Amaco 46 (cone 10), 547 and 101, In 50/50 and it's Vitreous at cone 8.

A recipe I've been making calls for 20% Red Earthenware, it fires to Cone 10. I've yet to fire them all the way to cone 10. Trying 2 types of local Earthenware. One is near Vitreous at cone 8. Closer at 9. 

I think you'll be mighty porous yet at 06. Unless you're using a 012 earthenware at like 75% and just using the stoneware to stretch it.

Sorce

 

 

 

Thanks so much, sounds like you're having lots of fun ! 

I've 2 lots of recycled clay that was thoroughly  dried and are currently  soaking in barrels, so nice and sloppy. It wouldn't be a problem to mix together when I've worked out ratio then wedge out on my plaster block.

I think I'll do a few experiments and see what works best. Good to know that it can be done , thanks for your knowledge. 

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On 9/18/2020 at 4:42 AM, Jools said:

Hi there,

I wonder is it possible to mix a stoneware clay and a earthenware clay together  and fire to come 06.

Any tips / advice greatly appreciated ,

Julia 

Low fire bodies (06-04) incorporate talc primarily as both a flux (magnesium) and to control thermal expansion. Low fire bodies without talc can have COE values above 12, and bodies with talc can have COE around 9-10. Boron is also used in low fire bodies as a flux: both magnesium (talc) and boron are lower temp melts. Cone 6 bodies use KnaO (sodium/potassium) as the primary body fluxes that begin to melt around 2050F. In addition, cone 6 stoneware bodies have COE between 5-6 typically. While you can certainly mix the two and fire low: any functional use properties will be lost. Secondly,, you will most likely have to make adjustments to the glaze because combining the two will create an entirely new COE value. 

Tom

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I think you'll have problems with glaze fit when using the blend as a low fire body. If you're mixing your own glazes you can make adjustments to compensate. If you're using commercial glazes, then you're stuck with whatever happens.

It may also be difficult to get a consistent blend from batch to batch since the water content of any particular part of the sludge will be different. It would help if you are able to mix each flavor into a fairly even slurry that doesn't have chunks of stiffer material in it. Variations in the proportions of the different clay bodies will mean you have to re-test and adjust glazes every time you mix a batch.  If you can mix it all at once that would save some headaches.

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