Testing Results

I’m very happy with the test results. Tweaking these recipes in my cone 8 kiln so that I can get as close to possible before taking up precious room in the big gas fired cone 10 reduction kiln. All of these recipes are based on the Leach 40 – 30 – 20 – 10 recipe method which so far seems very stable. Getting the specific gravity dialed in is important.

Testing rolls right along

So I’ve got all the chemicals I need to make a vast amount of glazes in my simple palate and color range. Testing to cone 8 in my electric kiln so I can tweak it as close as I can before putting it into the big gas fired kiln at cone 10.

  • Zircopax white over temmoku
  • White over Celadon
  • Temmoku over Celedon with a dip into the red iron oxide (FE2O3) as a differentiator test
  • Clear glaze by itself
  • Zircopax white by itself.

Im really excited about these simple glaze combinations. Along with red wild clay slip from the lake and black slip that goes to cone 10 I have a wide range of decorating possibilities to play with.

Previous Celadon glaze tests with incrementing FE2O3 from 2% to 12%


Testing the specific gravity of the glaze with hydrometer.


The only thing I may want to do different is to get more flux into the white glaze to have it run, almost like a Nuka style glaze over Temmoku.

John Britt’s Complete guide to High Fire Glazes has enough information to keep me busy for many years! Big thanks to Jay Benzel of Benzel Pottery for loaning it out to me.

Another thing I was working on was pulling technique and made a nice delicate serving spoon. Beautiful right?!

Not anymore! Haha! The spoon is just a spoon. ┬áThat’ll learn me to put stuff on the counter!

Celebrating Failure

Pretty much everything that could have gone wrong with this last firing has gone wrong.

Clay body cracks
Crazing
OLYMPUS DIGITAL CAMERA
Crazing reduces the strength of the vessel by up to 80% A short drop to the wooden floor split this right in half.
Blistering AND crazing
Blistering
Blistering
Pinholing AND Blistering
Pinholing like a CHAMP!
Even a bit of reduction in part of the kiln. Although I must say the reduction looks beautiful!

I’m picking up some dry materials to start testing my base glazes. At least I know that my chosen clay body tolerates overfiring very well.

I’m getting some witness cones (5, 6 and 7) to stack on each shelf and see what they do. I don’t understand whats happening yet. Olympic says that the kiln usually underfires if something is wrong rather than overfiring. The company that makes my clay body says that blistering happens from overfiring. The cones should tell the tale though. I need to get that straight before I drive myself crazier than usual.