Resilience Of 06, Recommendations?

[Norm Stuart]

Early civilizations did not use "earthenware" clay" fluxed down to Cone 06 with man-made frits.  They fired actual earthenware clay at higher temperatures in wood or coal fired pits or kilns.

 

The earthenware fruit bowl I posted above, which was fired to Cone 10, would survive thousands of years even if broken into a few pieces in the process.  I think the mistake continues to be confusing earthenware with Cone 06 clays.

 

I think you'll find Cone 5/6 stoneware bisque fired to Cone 04 has greater durability than Cone 06 clays when both are glazed with Cone 06 glazes and refired at Cone 06.  You'd gain a lot of additional strength firing even to Cone 1 or Cone 2, but I don't know of any commercial Cone 2 glazes for the art market.

 

Commercial ceramic factories currently work extensively at Cone 2.

 

Mark

I've made quite a few utilitarian wares with low-fire clay.  They hold up pretty well, but even those that are only a year or so old, wear relatively quick, and that's just with hand washing. 

 

I do wonder how early civilizations had their wares hold up so well?

 

Pres, I've kicked around the idea of firing cone 6 in my classroom.  But I do like the speed, as which I can get low fire projects through the process.  A five hour, "Fast Glaze" setting is a Godsend come the end of the term.

 

[Pres]

I usually had no problem getting things finished at the end of the semester. First off, all construction was completed 10 working days before semester end. All glazing was completed 4 days before semester end. End of semester cleanups took up 3 days when you got down to washing shelves, boards, wet cabinets, glazing areas, all wheels, all of the tables and sorting/rearranging drawers of tools and forms. Then there were final critiques every unload of glaze firings and then the individual grading conferences for every student. I loaded kilns in the mornings around 7am, and stayed until they were off usually around 5pm. These were fired slow up above 1100F. then turned to high. Cool down unloads were usually a little warm the next morning. Good thing I had two kilns running. I also had one kiln that had 4 sections-I usually only fired 3, but when crunch time came the fourth section went on.

[Benzine]

Yeah, I've only got the one kiln, which I sometimes have to share with the Middle School teacher, sharing is caring right?.....

 

Like you, I have a "Build" deadline.  During the winter months, that deadline usually moves, as we miss days, and such.  My goal is to have everything back to the students, by the last day of the term.  I usually fail at doing so. 

 

Another reason I've stuck with low-fire clay, is because the Middle School teacher shares my room.  He only bisques his clay, and the students just paint it.  So, he uses my slip, but I take all the scraps, he'd otherwise throw away. 

[Pres]

Gotta do what you gotta do. The JH's in our district had ceramics teachers that had been student of mine. The district decided they wanted to have more "crafts" in the JH that consolidated two JH's So new curriculum included ceramics. It worked out well for me as they would ask advice, and we ensured that clay coming into the stockroom worked for both sooo. . . . (read between the lines)

[Benzine]

Gotta do what you gotta do. The JH's in our district had ceramics teachers that had been student of mine. The district decided they wanted to have more "crafts" in the JH that consolidated two JH's So new curriculum included ceramics. It worked out well for me as they would ask advice, and we ensured that clay coming into the stockroom worked for both sooo. . . . (read between the lines)

Ha!  With experience comes wisdom, and the ability to covertly tell others what to do.

 

That reminds me of my second job.  I replaced a high school teacher, but his wife, taught Art in middle school and retired the same year.  She had a new room, and new equipment, including a nice programmable kiln.  She didn't know much about ceramics, and went with what her husband told her.  So she used the same clay he did, which was  a Cone 6 clay.  Problem is, when the new middle school teacher started, she had kiln issues.  I'm not sure if the kiln was rated for firing that high.  Either that, or the elements were shot already.  In either case, she wanted to move away from glazing the projects and just paint them.  So I suggested getting a low fire clay, and that way, she wouldn't have to deal with firing up to Cone 6.  That solved her problem.