hershey8 Posted September 2, 2014 Report Share Posted September 2, 2014 When a recipe calls for calcined kaolin, does that mean I can just bake kaolin powder in my kiln to calcine it? A clay/glaze supplier, I know, says it ain't that simple. I need a second opinion...and third and fourth and so on. ja Link to comment Share on other sites More sharing options...
perkolator Posted September 2, 2014 Report Share Posted September 2, 2014 just stick it in a bowl and fire to remove the chemical water. you can put it in a bisque load or simply fire it close to red heat. Link to comment Share on other sites More sharing options...
Mark C. Posted September 2, 2014 Report Share Posted September 2, 2014 No baking please -potters fire they do not bake or paint they glaze and fire Cooks bake painters paint You can bisque fire EPK in any form that will hold it. Mark This baking deal with the public has got to start with education and having potters call it baking and painting is just to much We make forms not cakes. It starts with us. Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted September 2, 2014 Report Share Posted September 2, 2014 Surely electric kilns toast pots. Link to comment Share on other sites More sharing options...
Colby Charpentier Posted September 2, 2014 Report Share Posted September 2, 2014 I know plenty of potters who calcine their own kaolin.. It leads me to believe that it is that simple... Reconsulting your supplier to find out their exact concerns (besides making money) might be worthwhile Link to comment Share on other sites More sharing options...
ayjay Posted September 2, 2014 Report Share Posted September 2, 2014 I was going to do this last week, (but then I eventually remembered where I'd put my batt-wash mix). Does the Kaolin need to be fired in a bowl which has already been bisqued, or can it be fired in a bowl which is being bisqued in the same firing? Link to comment Share on other sites More sharing options...
Mark C. Posted September 2, 2014 Report Share Posted September 2, 2014 The bowl can be green or whatever form you fire it it can be greenware. Mark Link to comment Share on other sites More sharing options...
hershey8 Posted September 2, 2014 Author Report Share Posted September 2, 2014 No baking please -potters fire they do not bake or paint they glaze and fire Cooks bake painters paint You can bisque fire EPK in any form that will hold it. Mark This baking deal with the public has got to start with education and having potters call it baking and painting is just to much We make forms not cakes. It starts with us. Correction: Cooks cook; BAKERS bake. Link to comment Share on other sites More sharing options...
Benzine Posted September 2, 2014 Report Share Posted September 2, 2014 No baking please -potters fire they do not bake or paint they glaze and fire Cooks bake painters paint You can bisque fire EPK in any form that will hold it. Mark This baking deal with the public has got to start with education and having potters call it baking and painting is just to much We make forms not cakes. It starts with us. I'm with you Mark. My coworker says "Bake" sometimes, and it annoys me. For one, it's to Middle School students, who are well beyond simplifying things. And two, as you mentioned, we aren't eating the items, so it's not baking. Link to comment Share on other sites More sharing options...
hershey8 Posted September 3, 2014 Author Report Share Posted September 3, 2014 Well I wonder if there are different levels of calcining. The guy I was referring to indicated that his version not only eliminated chemical water; it actually changed the material in some other chemical way. But I guess, bisqueing is adequate for potters, ceramists, cooks, bakers, and painters. Link to comment Share on other sites More sharing options...
neilestrick Posted September 3, 2014 Report Share Posted September 3, 2014 Once the chemical water is burned out, there's really not anything else that can happen to the kaolin. I suppose you could fire it so hot that it fuses, but what would be the point? Just bisque fire it and you're good to go. Link to comment Share on other sites More sharing options...
Mark C. Posted September 3, 2014 Report Share Posted September 3, 2014 (Correction: Cooks cook; BAKERS bake.) sounds like a 1/2 baked idea Link to comment Share on other sites More sharing options...
Babs Posted September 3, 2014 Report Share Posted September 3, 2014 Here I am eating my biscuit sorry, cookie, should that be bakie, and wondring why one would want calcined kaolin? Link to comment Share on other sites More sharing options...
TJR Posted September 3, 2014 Report Share Posted September 3, 2014 No baking please -potters fire they do not bake or paint they glaze and fire Cooks bake painters paint You can bisque fire EPK in any form that will hold it. Mark This baking deal with the public has got to start with education and having potters call it baking and painting is just to much We make forms not cakes. It starts with us. I agree with Mark. Let's use the vocabulary. I don't bake. I don't paint, I glaze. I definitely do not "play with clay", I work in my studio. I am a serious artist. Come on people. Let's step it up a notch. TJR. Link to comment Share on other sites More sharing options...
hershey8 Posted September 3, 2014 Author Report Share Posted September 3, 2014 Okay, the word cops have it. Fire and glaze. Link to comment Share on other sites More sharing options...
hershey8 Posted September 3, 2014 Author Report Share Posted September 3, 2014 Now back to calcining. Babs, you asked why? Apparently, kaolin, when "fired" to the appropriate temperature, gives up chemical water, which deals with shrinkage issues and LOI. I have seen it mentioned in some recipes, though right now I don't remember the specific ones. Calcined kaolin has other uses outside the realm of pottery. And if I am correct, some of those uses require that it be "fired" hotter than yer average potter's kiln. Thanks to all, and to all a good night, good morning, good day, good grief. LOI....er... LOL. ja Link to comment Share on other sites More sharing options...
neilestrick Posted September 3, 2014 Report Share Posted September 3, 2014 When you calcine kaolin, you burn off the chemical water as well as any other organics- the stuff that's listed as L.O.I (Loss On Ignition) when you look at the makeup of a clay. So basically you're pre-shrinking the clay. In the case of kaolin, you're getting rid of about 15% shrinkage, which is significant if you've got a glaze or such that's high in kaolin. For instance, if you've read the threads about kiln wash, we always mention calcining half the kaolin for recipes that have 20-30% in them. By doing so you reduce the shrinkage of the kiln wash, which helps keep it from flaking off. Link to comment Share on other sites More sharing options...
hershey8 Posted September 3, 2014 Author Report Share Posted September 3, 2014 When you calcine kaolin, you burn off the chemical water as well as any other organics- the stuff that's listed as L.O.I (Loss On Ignition) when you look at the makeup of a clay. So basically you're pre-shrinking the clay. In the case of kaolin, you're getting rid of about 15% shrinkage, which is significant if you've got a glaze or such that's high in kaolin. For instance, if you've read the threads about kiln wash, we always mention calcining half the kaolin for recipes that have 20-30% in them. By doing so you reduce the shrinkage of the kiln wash, which helps keep it from flaking off. Thanks for that great information, Neil. That helps me to understand it better. j Link to comment Share on other sites More sharing options...
Mark C. Posted September 3, 2014 Report Share Posted September 3, 2014 I have a great cake recipe that uses 30% calcined EPK the rest is high fire clay and finished with sprinkeled bakers flour then painted with colorants Bake at 2380 for 12 hours- cool 18 hours serve warm Mark Link to comment Share on other sites More sharing options...
Babs Posted September 3, 2014 Report Share Posted September 3, 2014 I have a great cake recipe that uses 30% calcined EPK the rest is high fire clay and finished with sprinkeled bakers flour then painted with colorants Bake at 2300 for 12 hours- cool 18 hours serve warm Mark Is this food safef? What no corn syrup?? Link to comment Share on other sites More sharing options...
Mudslinger Ceramics Posted September 4, 2014 Report Share Posted September 4, 2014 Here I am eating my biscuit sorry, cookie, should that be bakie, and wondring why one would want calcined kaolin? ........because it makes an excellent facial cleansing mask!! http://craftbits.com/project/facial-clay/ Irene Link to comment Share on other sites More sharing options...
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