WEEK 11: Testing clay and slip in the kiln

In preparation for clay-work that will involve wheel thrown pots as well as figurative sculptures, I wanted to test my natural earth pigments as part of a slip for surface decoration. I knew that the oxides and other minerals would have an effect on the colours and I had no control over it. I was excited to see what would happen…

I have gathered a view experiments that will be going into the kiln today (30 April). Here they are in their bone try state:

Here are some photos of the slip, the ‘test biscuits’ made of 3 different types of clay and sgraffito detail BEFORE they went into the kiln.

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It was the first time using my kiln in our new house and I was a bit nervous to be honest. But I am happy to report that everything went well. Nothing burnt down, no-one was injured and nothing cracked.

Here are some before and afters of the items that was fired:

So my finding was: The lovely red pigment from the Cederberg became slightly lighter but stayed a dark dusty pink. The green pigment from Stilbay became a light pink! The yellow clay from my house became an burnt orange that has a lot of chroma.

It was very useful to see what the pigments did as well as the wild clay. VERY interesting. I will be deciding which combinations work best, but I can see that I will need another colour in the mix… So more tests coming.

Before and after of the wild clay pots:

I am not sure if I like the orange. I think if I put it on a program that increases the heat, it will become more red. I will have to try. I also noticed that the sand that was still in the clay became little white specs. I don’t mind it too much. The sand might have helped the clay be workable. The manganese oxide slip stayed the same colour.

I am please with the experiment. I want to try to see if I can make some bigger pots and intersect them. This time I will try to take some clay with me into the mountain to get some interesting textures and see how I can perhaps work them into the pots for a more interesting shape that will link with my concept of interconnection and repairing connections.