Glazing
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Some of the glazes used in my last session |
One of the things that I do enjoy is playing around with my glazes; experimenting, layering - and generally making a mess - to see what happens!
I have often referred to ceramics as 'a sweetie shop full of possibilities and potential'; well, the glazing is the icing on top of the bun and the fancy box and bow all rolled into one!
However, I have also been known to call it "painting colour-blind with mud" and that is very true too!
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My glaze ingredients shelves |
I mix all of my own glazes and they all start life as a combination of mostly white powders. Firing mostly in the Cone 6 range (around 1200 degrees C) most of them include refined or processed rock and mineral ingredients such as potash feldspar, barium carbonate or nepheline syenite, as well as china clay, flint or quartz. There are usually other ingredients too depending on the effect that I want to achieve, and then I create the actual colour using oxides.
So, after weighing, mixing, sieving and labelling, I am left with a mixture that is usually about the thickness of single cream - and which bears no relationship at all to it's finished colour or effect!
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The mixed glazes - the colours that you see are nothing like the finished effects |
For example, a glaze that it brown when 'raw' could be blue when it is fired. Some of the cream coloured mixtures could be green, they could be blue, they could be white, they could be clear.... The three black mixtures shown above are a good example; One is actually a glossy black glaze, another is a gold lustre while the third creates a purplish blue!
And then there is the combination effect! A glaze that is one colour on it's own, can change completely in combination with another ingredient or glaze containing that ingredient. A good example is a glaze containing chrome; on it's own it usually makes green, but add tin or zinc and it turns pink. Or a purple that turns brown, or a blue that turns purple.... And even a simple addition of a clear glaze can make a huge difference.
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A glaze test tile showing the effects of overlayering |
This was a test tile that I made for a new glaze mix I wanted to try. I added eight different colouring oxide combinations and painted a sample of each onto the tile and then I painted a line of a glossy clear glaze over a third of each sample and a line of matt clear glaze over another third, creating the results you can see.
... so when you think that I have a range of around 50 glazes that I already use - and I keep trying more all the time - the decorative possibilities are endless!
The only problems are trying to remember how each glaze interacts with the others, will it bubble or go glossy, will it change the colour, which order they need to be layered up in, how thickly, whether they will be opaque or transparent, how sensitive they are to kiln position and temperature......
Oh - and all the washing up again afterwards!