In the glaze room at the Glasgow School of Art Ceramics Department - wearing my fashion apron! Photo by Cara Broadley

Photos from weeks 11 and 12 are now all uploaded, sorted and documented. Please click here to view them. During those couple of weeks I started with some glaze testing.

It’s been a fascinating process, and something I haven’t done much of before, apart from our Glaze Chemistry classes with Tony Flynn at the CSA and some testing for my raku project a few years ago. So I was very excited to re-acquaint myself with the process and to learn about the effects of ceramic materials in the UK.

As you may be well aware, ceramic materials vary according to the country and mine that they come from. Many are not available internationally or have different brand names. Glazes which result in one effect in Australia may in fact turn out to be completely different in the UK, once the local materials are substituted.

So the aim of this part of my research is to come up with some glazes that I can use here in Scotland - it makes sense to use materials mined locally, where possible. Most of the materials we have at the Glasgow School of Art come from suppliers in Stoke-on-Trent in England.

First I sat down and thought about the qualities I want my glazes to have:

• Glazes to be suitable (fit well) for the porcelains I intend to use
• Glazes to be high fired (cone 8 - 10) so that the porcelain body I’m using can vitrify.
• Glazes to be glossy or satin/matt - this is because I’d like to use printing techniques and they would probably not work as well with dry glazes.
• Glazes to be oxidised. This is because I’m most comfortable with using electric kilns. They fire consistently and I know how to use them. If I get a kiln in the future, it’ll most likely be an electric. Some people prefer gas because the colour results are so much more beautiful - and I’d definitely like to learn to use gas kilns properly - but for now, I think electric gives me enough scope.
• Glazes to be suitable for functional ware - this is not because I intend to make functional ware for my project, but because I’d like to have the option in the future, if I want to make functional ware, to have glazes ready for that eventuality.
• The colours I decided on are clear/transparent, white, black and an imitation celadon - a turquise/greenish/bluish colour (celadon is a reduction glaze).

The next step was to find and collate recipes for these glazes. I settled on two UK publications: “The Glaze Book - A Visual Catalogue of Decorative Ceramic Glazes” by Stephen Murfitt and “The Potter’s Book of Glaze Recipes” by Emmanuel Cooper. Both of these are popular with the local students and other ceramic artists in Glasgow. I also asked Wendy Kershaw, the GSA technician for any GSA school glaze recipes, and she very kindly let me look through her own glaze notes and pick out any I wanted to test.

From Australian publications I chose “Glazes for Australian Potters” by Janet DeBoos, who is my supervisor at the ANU (I own this book). I believe that it’s out of print now, but it’s excellent, so if you see it in a second hand bookshop, snap it up. When I looked it up on Amazon, it was on sale for £399 (!).

I also referenced my glaze notes from the CSA undergraduate Glaze Chemistry classes, which were written and collated by Tony Flynn and distributed to students in my year. These notes included some basic CSA glaze recipes.

Last but not least, I took a couple of recipes from Anton Reijnders’ “The Ceramic Process”.

After I had quite a collection of recipes I entered them all into Excel on my computer and arranged them based on their firing temperatures. Then I made glaze testing sheets, on which I paired up glazes that used similar ingredients. Here is an example: page10_ox_glazesheets.pdf The testing sheets allow room for taking notes during the testing process.

All that took most of week 11. By the end of that week I had a fairly good idea of the type of ingredients that most stoneware and porcelain glazes consist of. The glazes I was interested in seemed to be simply a repetition of the same ingredients in various quantities. Since this blog entry is getting a little long, I might link a page here with some general basic observations for anyone interested (watch this space).

Week 12 on the other hand was spent mostly in the glaze room. The mask tends to get a bit uncomfortable after a while, and so do the gloves, so I only managed to test about 2 glazes a day. It seems like a pitifully small number, especially since I remember Tony Flynn commenting during one of our lessons that he was able to do all the line blends he set for our entire semester in one afternoon. Maybe I’ll get faster.

This entry was posted on Friday, October 12th, 2007 at 10:04 pm and is filed under Ceramics, GSA, MPhil, Scotland. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.