Saturday, March 30, 2013

Crystals On The Beach

Crystalline vase 170mm high (6 3/4 inches)

This 220mm (8 3/4 inches) pale green vase did not photograph well in the bright sun.

The vase has very pale green on green crystals.

There is a spectacular waterfall of colour on the rim where the outer crystalline glaze meets the inner glaze,

A page from my kiln log.

Glazing, firing, waiting for the kiln to cool. Glazing, firing, waiting for the kiln to cool. Gl....... The cycle of work continues through every day regardless of Easter as exhibition deadlines loom closer.  In the days that followed my previous post I realized that there was not sufficient time to have fountains made, tested, and any technical issues sorted in time for exhibiting in Oamaru in April, so a change of direction was called for.  I opted to do crystalline glazed pots, and managed to get the pots made and dried in record time, by putting them on wire racks over the kilns as they were bisque firing some of my sculptural work.

I decided to make up four different glaze bases, two of which I have used before, and two more that interested me.  I would use the first glaze firing to test all four of these, and use them on the smaller of the pots.  Out of that firing, I had two pots that worked well, two more that did not grow crystals, but were a good colour, and another pot that was very under fired, and a couple of interesting tests.  One of the pots that worked (the one in the first photo of this post), had one of the untested glazes on.  Ha, Ha... maybe I shouldn't bother testing glazes ever again!!!  I was very pleased with the definition and detail of the crystals. 

I had a good look at the pots, tried to think about what had worked and what had not, then glazed enough pots for a second glaze firing.  I finished firing the second kiln load yesterday.  

To give you a bit more idea of what goes on in a firing of a crystalline glazed pot, I have included a photo of my kiln log from the second crystalline glaze firing. I have a manual kiln, with no controller, so I have to twiddle simmerstat knobs, note temperatures, and keep track of the progress of a firing, by writing it all down on graph paper. The numbers along the bottom of the graph are the hours.  I started the firing just after 8 in the evening.  Below the time line are comments such as "All 1.5"  These refer to the simmerstat settings on the kiln.  If you look along a little way, you will see me turning the kiln on Full just before 3 in the morning, and the kiln getting to peak temperature at just after 7 in the morning.  The numbers up the left side of the graph, from 0 - 13 are temperatures.  I work in Centigrade, so the top one is 1300 C.  This firing reached about 1275 C which is 2327 Fahrenheit. 

You will notice how the kiln is fired to the peak temperature, then the temperature drops to about 1100 C, and is held for several hours.  This time where the temperature stays around 1100 C very important, as it is where the crystals do their growing. You will see a short dip in temperature after about 2 and a half hours, this was done to form a growth ring in the crystals.  You will also see a two hour period at the end of the crystal growing time, where the kiln is held at a lower temperature, this encourages the crystals to have a defined margin around the outside. Sometimes this can become a dark outline.

There is rarely enough room at the bottom of the graph to write all the information that I need when I am doing the crystal growing part of the firing.  I have to check the kiln every 10 to 20 minutes throughout that period, so I write any information that I need to record in a block above the timeline.  You may be able to read some of that... , or maybe not, my writing is a terrible scrawl!  Most of my notes are of temperatures, times, and simmerstat settings.

I am currently waiting for the second glaze firing to finish cooling.  I should be able to unload it first thing tomorrow morning.  

Easter is late summer for us.  This is how things looked this morning at the beach!

The exhibition in Oamaru that I mentioned is one that the potter's group in Oamaru is holding at their clubrooms.  The Oamaru potters are a friendly group of people, and I am looking forward to catching up with them. The exhibition opens on Saturday April 6th at 7pm, and runs until April 12th. You will find it at Pottery-On-Tyne, 44 Tyne Street, Oamaru.  Bevin Stowell, from Ashburton, and I are both guest exhibitors.

Happy Easter!


Raindrop said...

Thank you for this post Peter. As usual, informative and inspirational! The most lucid explanation I have read of firing crystalline glazes.Best wishes for setting up the Oamaru show. You and Laura deserve a great time and a bit of relaxation after your efforts.

gz said...

Beautiful rim...and lovely beach too!!

Angie said...

Stunning ...the pots and the setting make for the most beautiful shots.
I have to say I love the patterns that have formed ...and the colours that developed. I think a 6ish" pot that looks that beautiful should be snapped up ...and its easy to carry home.
Find it hard to think of Easter in Summer ....up until yesterday we had zero C at night ...and hail showers during the day.!!!

Have a Very Happy Easter ....and I hope the exibition goes well. xx

angela walford said...

they are stunning pieces peter! and love the pos on the beach...great light!! and great to hear you do all this with a manual da man!

smartcat said...

Gorgeous pots, settings and all.

Toes crossed for a great success at the show!

Happy Easter to you and yours.

angela walford said...

that was pics on the beach..

Michèle Hastings said...

a beautiful setting to photograph beautiful pots.

Teresa Evangeline said...

wow. What a gorgeous setting for your beautiful pots. Do you sell and ship to the US by any chance? Please let me know @

Peter said...

Hello Raindrop,
Lovely to hear from you, and thank you for your kind words. I think that I might do a special post about crystalline glazes soon, and will try to photograph the pot at various important stages. Glad you found the information "lucid", I wrote it whilst rather tired and hoped that it still made sense!

Hi Gwynneth,
I was tempted to cut off the rim and frame it!!

Hello Angie,
Goodness, zero degrees at night... brrrrrrr. I guess we will be having frosts about a month from now, but nothing like the weather that you have been having!! Easter at the opposite end of the year to you is a little strange if you are used to the northern hemisphere. We're almost autumn here, about the time of year I think of Harvest Festival with apples and pears all safely gathered in.

Gidday Ange,
Thanks for that. One day I will treat myself to a controller for the kiln... shockingly expensive here though. Trotting out to the kiln shed every 10 to 20 minutes for six or seven hours when doing the crystal glazing soak is probably good for me though, more fun than a gym!

Hi Smartcat,
Good to hear from you. Keep those toes crossed, the exhibition deadline is approaching very fast!! Glaze firing number 3 just starting as I write this.

Hi Michèle,
Good to hear from you. Taking photos of pots at the beach is a new discovery for me, such a great improvement from my terrible attempts at light boxes and so on.. and lovely to get out into the fresh air!

Hi Teresa,
I can sell and ship to the US. I'll be in touch with you.

Jill M Hodgson said...

Absolutely stunning and perfect setting to show them.
Happy Easter to you both..... Jill

Peter said...

Hi Jill,
Aren't we lucky being so close to the sea, it is a lovely place, and it was nice to find a good excuse to "extend my studio" there for an hour to take photos! Happy Easter to you too.

Anonymous said...

Happy Easter Peter and Laura.

What a fabulously detailed explanation of how you grow crystals on your glaze in the kiln!

It appeared you would need to be awake all night long in order to fiddle about with temps and things. Is that so? Such a laborious task and I wonder if you fire during the daylight hours also, to make it easier on yourself.

The vases are amazing. I particularly like the pale green one.

Hoping to see you in Timaru next month.
Have a fun time with the friendly potters of Oamaru.


Lopdell House Gallery said...

Absolutely gorgeous Peter. You excel yourself as always.

Thanks for sharing

Peter said...

Hi Sue,
The crystalline glaze firings are so long that it is actually kinder on me to start them in the evening and do all the complicated stuff through the next morning and into the afternoon. If I start them in the evening I can have the kiln firing fairly slowly through to when it is a good red heat, about 700 degrees. If I time things right it means I get to sleep from 11ish through to about 3 in the morning, and ... if I'm very lucky, another short sleep before having to monitor the kiln as it comes up to full temperature between 6 and 7 in the morning. Then I get really busy trotting out to the kiln every 10 to 20 minutes (sometimes more, but not much..), until the firing is finished in the early to mid afternoon. It is all rather silly really..., but it is nice when you find one or two good pots in the kiln when you open the lid after the firing! Px

Hello Lisa, how lovely to hear from you! It's funny we were talking about you just yesterday, wondering how you were. Hope you have had a great summer, and are enjoying all sorts of creative things! Kind thoughts, P&L and our two feline friends.

Anonymous said...

...So you spend about 20 hours on a crystal firing... Hmmm!

The result is (dunno how to HTML italic the 'is') Beautiful though!

Peter said...

Hi Anonymous,
Mmmm... somewhere between 16 and 20 hours seems about right.... I should have been a long distance truck driver or a night watchman! P:)