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Technical - Crazy Glazes

Making your signature finishes, unique surfaces and distinctive designs | author: Jenny Orchard

trange brews or original recipes? Glazing has so much in common with cooking – you can slavishly follow the recipe book or you can let your senses and available materials play a bigger part.

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Glazing – is it alchemy or science, or just having fun with glazes, messing with finishes and oxides in much the same way as a painter paints?

My aim here is to help you make the most of commercial glazes – to clear the haze on the glaze!

The pure joy and beauty of being a ceramic artist (as opposed to only a painter or only a sculptor) is that you operate across mediums – as sculptor, painter, decorative or figurative manipulator of the elements, and alchemist and giver of form, colour, illusion, mood and message.

Remember, your work will always carry a message, be it about the use and approach to materials, your philosophy on life, or – the universe and everything. The glaze will invigorate your finished piece, as well as enhancing the message inherent in the form.

Glaze (detail), 2003, earthenware... Glaze (detail), 2003, earthenware...

When working in earthenware there are many choices. The colour and quality of the clay is juxtaposed with the surface – matt or shiny, deeply textured or smooth – and this, along with the firing conditions, needs to be taken into consideration when approaching the decoration.

Being a painter/sculptor/ceramicist (I always feel best described as an artist) is no easy task as total commitment and focus is required. If this is achieved your work will express qualities undreamed of during the difficult process leading up to your completed artwork.

Here is my approach to working with earthenware. I use mostly modified commercial glazes, oxides and frits.

Ten general guidelines to working with commercial varieties of slips and glazes:

Experiment with your materials and firing schedules.
Vary your application techniques. Some glazes work well applied with a spoon, as they may crawl which can be attractive as a texture. Fine builders’ sand, added to a glaze at around half a cup per litre, will give a chunky texture. I have used Cesco earthenware brush-on glazes in this way for many years with good results. Sometimes a fine, minimal application of glaze can work best. The result will vary depending on the clay used and its surface quality.
Always make notes of the process you followed and the firing temperature – very important unless you have a photographic memory.
Bright colours, e.g. red and orange cadmium glazes, work best fired at lower temperatures, around 1000ºC.
Copper, cobalt and manganese oxides applied straight onto the clay surface, work well fired at around 1120ºC. This ensures they fuse with the surface.
Underglazes can be used under, and over, clear and white glazes, giving a variety of subtle finishes.
Coloured glazes can be used in much the same way as paint on canvas. Apply brush-on glazes as you would for acrylic paint and underglazes as you would for watercolour paint. When applying two glazes to the same surface, never over-fire or soak for too long (ten minutes at the most).
Glaze can be applied onto a textured surface and then wiped back to reveal the colour of the clay. This works well with terracotta clay.
Play with your medium. If at first the surface does not please you, re-fire at another temperature or apply more glaze and re-fire.
Have fun – this will come across in your work!

Glazing for me has always been a process of constant experimentation, accidents and pure luck.
Good luck with yours!

Jenny Orchard’s work is represented in the National Gallery of Australia, all state galleries and various regional galleries, as well as collections in Japan and America. www.jennyorchard.com

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