Friday, March 20, 2009

Glazed and Glassy Eyed

I have been getting pots ready for the kiln this week. I have done two bisque firings in the electric kiln so far, and hope to do a glaze firing in the electric kiln tomorrow. I also shared a glaze firing this week in a gas kiln that belongs to my potter friend Marion. I have also set up a little display of my work in the window of the Stuart Street Potters Co-operative, of which I am a member, which occasioned a trip to Dunedin. I'm working fairly long hours (as usual), so tend to have a glassy eyed look by the end of yet another day glazing. The photos are of some of the bowls and mugs that I glazed yesterday, and of bottles of glaze that start to clutter up the table throughout the glazing process.

I write the glaze recipe on the bottle these days as well as the name or number of the glaze. I find this more helpful than trying to rummage for the recipe in my glaze book. I hate using small quantities of glaze, as it makes the application much more difficult and slow, but I frequently have to endure it as I am still in the process of narrowing down the number of glazes that I use and mostly do small runs of things, one off pieces, and glaze testers. I have got about 4 "stock" glazes now that I do keep in larger quantity made up. There is a nice shino, a useful iron glaze, and a copper/rutile chun glaze that I usually have several litres of.

You may notice that three little bowls in one of the photos have a thick build up of glaze and dribbles and runs. The bowls have 3 layers of glaze on them, and should turn out a nice chun (jun) with mysterious optical blues, aqua greens, and maybe a hint of pink. Glaze application on these has to be thick and uneven for the best effect.

People who haven't done potting, or have not seen the process, ask me how glazes are applied. The glaze is applied as a liquid, with its powdered ingredients mixed with water. Mostly I pour glaze into the inside of a mug or a bowl, swirl it around, and tip it out again. Then I dip the object upside down into a bucket of glaze to do the outside. Sometimes I pour glaze onto the outside of a pot or a bowl, and sometimes I brush glaze. The glaze dries onto the pot as the water evaporates away. Usually the glaze is fragile and easily damaged when it is dry, so it is something of a relief to get the pot safely loaded into the kiln for firing. Some potters spray the glaze onto the pots. The glaze has to be fired to make it permanent and to turn it from a powder into glass. People don't always realise that it needs this step, and are surprised by the grey, drab look of the unfired glaze.

More glazing still to be done today, and for the next few days, as I am working towards a firing of my wood fired kiln.

For those who haven't already done so, do have a look at Jimmy's blog,
It is a beautiful collection of photographs and thoughts, and well worth a visit.


Judy Shreve said...

You have been busy - and out of everything we do as potters - glazing wears me out the most. I've never seen glazes stored in bottles like that. I save large yogurt containers to mix my tests in, but I bet the bottle shape is better for pouring. Do you mix in another more open container & then put it in the bottle for storage? I also put the glaze recipe directly on the glaze bucket. I find it much easier to remake the glaze that way.

One of my enticements for moving to earthenware is how glaze/slips are applied. I like working at the leatherhard/green stage & most of the glaze/slip work is brushed. That also means I don't need big containers for dipping. It's probably cause I just don't know enough yet -- ignorance is bliss -- but it appears that there is more control in application with earthenware. We'll see!

I'm looking forward to seeing your pieces fired. Those pieces with built up glazes that will move & mingle are always exciting to unload.

Peter said...

Hi Judy, good to hear from you.
I mostly mix glazes in buckets or bowls, depending how much I am making. The bottles are for storage. My local hardware shop kindly sold me their old paint stirrer, which is very robust and fits our electric drill. I still sieve my glazes, but a good stir with the paint stirrer means that I only have to put them through a coarse sieve, and then through either a 60 mesh or 100 mesh sieve (depending on the glaze), and the whole operation goes much faster than it used to.

I finished glazing the pots for the electric kiln today, and got in from loading them by 8.30pm this evening. It is starting to get dark here not long after 7.30pm, so I am beginning to feel like hibernating as winter gets nearer.
I will fire the kiln tomorrow (Saturday), and should be able to unload it on Monday morning.
The kiln was still warm from unloading a bisque firing, so the pots will have a chance to get really dry overnight.

I love earthenware too, and would like to do more of it. There is something very satisfying about decorating with slip when the pot is wet or leather hard, and earthenware clay feels warm and honest to me.
Best Wishes. P.