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Reclaiming Porcelain....what Went Wrong?


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Not sure if this goes in this forum or the studio, so feel free to move it if it's wrong.......


Well, recently I tried porcelain for the first time and all was good until I tried recycling it. I did everything I normally do w/ stoneware (let scraps dry, rehydrate them in water, then dump wet slop into a plaster mold I use). The next morning I wake up to find what I thought was nice clay ready to be wedged....WRONG! When I picked it up to wedge, it immediately crumbled and became unwedgeable. Its still moisturized, but in a bunch of tiny, crumbly, chalky pieces. Thats the other thing, as soon as I started hydrating it, the stuff that collected at the bottom of the bucket was real chalky. But thats probably what its supposed to be like, not sure since this is my first experience w/ porcelain.


So, what did I do wrong? I would really like to reclaim it, as I really enjoy working with it and getting more isn't the most convenient method (must drive 3 hrs to pick up b/c shipping is too expensive). Any advice is appreciated. I should mention I'm using a ^6 domestic porcelain from alligator clay.

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Porcelain does not reclaim like stoneware or white stoneware clays.

The key is to keep it wet.

Once it dries its harder to slake and takes lots more time.

I toss my dry trimmings as I all my work is in porcelain.

all my wet scrap I have been pugging in a peter pugger.



PS this is cone 10 porcelain which I speak about

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Akin while I can't say for sure but something is lost in your slop water that the clay needs. Certain porcelains have a chalky propensity like epk. Also certain ingredients in clays are water soluble, and maybe you're missing this. But this subject has been discussed in past.


Stone ware and porcelain are 2 different monsters. Have you tried throwing porcelain scraps in bucket along with tray slop allow that to dehydrate naturally then to plaster bat?

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Guest JBaymore

Cone 6 "porcelains" (if it isn't high fire.... for me it is not porcelain) have to be fluxed down to be vitreous at cone 6.  The usual "culprit" for this function is Nepheline Syenite, since it has a higher ratio of fluxing oxides to alumina and silica compared to feldspars (spar is used at cone 9-10). 


Neph sy is slightly soluble in water.  As the clay is used and the local water (which might have a different Ph than the suppliers water) gets mixed into the clay, and as the clay sits for TIME in that water... the chemistry of the water can change.  One of the characteristics of this change is it will KILL the plasticity of the reclaimed clay. The more acidic your local water... the more (and faster) the issue will show up.


So....... pretty likely some or all of the issue.





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I reclaim every scrap of my cone 10 porcelain, but I make sure it is a combination of my slurry and trimming scraps. If I don't include the slurry, with its fine particles, the clay is short.  Everything goes into the bucket. When I have enough, I mix it with my hands, pour it onto plaster and wedge it up when it's ready.  I don't have any trouble throwing with it or carving it for my sgraffito pieces.  I have done this with several kinds of porcelain, all cone 10...

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