Saturday, April 6, 2013

Peacock Feathers and Cloud

I found some treasure in the kiln on Friday morning.  These lovely crystals had grown on one of the pots over the course of the firing.  The firing went to 1270 Celsius (2318 F) and then the temperature was held for 2 hours at 1067 C (1952 F), and for a further 3 hours at 1135 C (2075 F).  I tried this schedule after reading a paper by F. H. Norton, The Control of Crystalline Glazes, that had been presented to the American Ceramic Society in 1937.  Under laboratory conditions in a special test kiln, Norton did extensive study of zinc silicate crystal growth, and discovered much that will be of value for my own experiments.  He mentioned growing crystals with green centres and a blue border, and I followed a similar firing schedule to the one he was using.  Here is a link to The Control of Crystalline Glazes, it is a PDF file.

The crystals are on a tall vase that I only just and so managed to fit into my kiln. After taking the vase out of the kiln, and grinding glaze runs from the foot, I raced down to the beach and took a few photos before packing the vase in a box.  Then the tall vase, and 5 other pots were taken through to Oamaru for the exhibition that opens tonight at Pottery-On-Tyne.  The vase looks terrific in sunshine and the blues really sparkle, but it takes on a grey look when the clouds come over.  When the sun is out, the crystals make me think of peacock feathers!

Crystalline glazed vase, approximately 20 inches high (508mm)

Another pot that was in the same firing was this one, with a copper green glaze. 

Crystalline glazed bottle 15 1/4 inches tall (390mm)

Interestingly, the crystals are quite a different shape from the ones on the tall vase.

These crystals make me think of angels or dancers!

Must go now.  We have a stall at the Waikouaiti Food Festival at the race course today.  I hope to go back and take some photos.  Really cold start down there for us, our stall is in the shade of the grandstand and there was a frost overnight. Brrrrrrrrrrrrrr!


Sandy miller said...

Thank you so much for posting Norton's paper! Definitely has my wheels turning! Excellent stuff. Pots are just beautiful!

Teresa Evangeline/Bayou Summer said...

Simply gorgeous.

Angie said...

Those crysal patterns are amazing ...the peacock close up blew me away ...just kept staring at its beauty.I bet Laurs could use it as inspiration for a canvas.xx

Angie said...

oops ...not sure what happened to my typing there!!!

Arkansas Patti said...

Your crystals are just amazing Peter. One could get lost in them.

Anna said...

beautiful results!

raindrop said...

Congratulations Peter! You have created beautiful pots again. Edgar Degas ballet pastels spring to mind for the turquoise pot and William Morris' wonderful peacock feather pattern for the blue;and thank you for sharing so much. I am tempted to be diverted from my planned path! The Norton paper is a gem; so good of you to share it.

Peter said...

Thank you everyone for your comments, and for taking time to write, it is lovely to hear from you. Glad that the Norton paper has been interesting for Sandy Miller and Raindrop, who knows what it may inspire!! I would love a test kiln like the one that Norton used, I like how the floor of the kiln with the test tile can be lowered for study.

Back to work again today and I'm busy making more large pots for crystalline glazing. These will be about 20 inches in height when fired.
Kind Thoughts to you, P.

Pat - Arkansas said...

Ooooh! Lovely, lovely!