Slip Cast Bowl

To create my slip cast bowl I first created a solid form using red clay. For my form I chose a moth as I thought it would make a unique bowl and would give my bowl an unusual shape, it would also allow me to experiment with different patterns and decoration methods. After I made my form I began to smooth it off with a rubber kidney and got rid of any undercuts that would make the bowl difficult to cast.
After my form was completely smooth I made a barrier around my form using a piece of plastic sheeting and clay to seal off all the edges. Once the form was completely incased I used plaster of paris to fill the mould. I removed any excess water coming from the plaster and waited for it to dry out. This took a few days.
When dry I was able to remove my form from the centre of the mould, I then had to clean it to ensure there were no left over bits of red clay which could effect the colour of my first casting. Once my mould was completely clean I then poured in slip to fill the mould. I allowed this to dry leaving about 1 cm thickness around the edges. One the 1 cm thickness has formed I removed the excess slip. This was then allowed to dry out to allow the casting to be removed easily from the mould.
When I removed my casting from the mould it was very fragile and broke in the removal process, I could have improved this by allowing my casting to set longer making it thicker and more durable. Although I cleaned the mould of the majority of the red clay before I created my casting it still left a light layer of red clay on the surface of my casting giving it a red tint. This isn't the look I wanted to achieve but I thought it worked well with the theme of my piece as the moths colour scheme consists of different reds and browns.
Due the the fragile state of my first casting I decided to use a different method of creating my bowl. I decided to press mould my form. To do this I first rolled out a 1 cm thick piece of clay to fill in the mould I had created. I then placed this thin sheet of clay over my mould and began to press the clay into the form I had created. I then removed the excess from my mould to leave a clean edge. This was also allowed to dry and shrink slightly before I was able to remove it from the mould.
This form of casting was a lot more sturdy due to the thickness of the clay allowing me to handle it easier and create a more durable bowl.

To decide what decoration to use on my bowl I experimented with different slips over different clay. I first placed white slip over a red clay tile which would then be decorated with sgraffito (the technique of scratching into a surface creating texture or line) and coloured slip over a white clay tile which would be used to create a similar effect allowing the lower colour to show through.






Equipment used-

• Red or White clay
• Plaster of Paris
• Clay tools (knife, kidney ect.)
• Plastic sheeting eg. Linoleum
• Rolling pin
• Wet sponge

Ceramics can be a very dangerous activity if not practiced properly and safely. Here are some health and safety issues to consider whilst creating a ceramics piece. -

• Silica dust exposure- Clay dust contains crystalline silica this is known as 'free silica' and poses a serious health risk. The dust particles cannot be seen by the naked eye so the person working with clay with little knowledge would not know they were at risk. The dust can also remain airborne for long periods of time in your working area allowing it to penetrate deep into the lungs during the working process. This exposure to the crystalline silica can lead to serious lung damage and ultimately the lung disease named silicosis.  To prevent exposure to the silica certain precautions should be taken, these include-

1. Ensuring that clay is kept damp during use.
2. Do not dry sweep when using clay floors must always be washed down with a wet cloth.
3. Clean all surfaces with a wet cloth after using clay.
4. Any spillages should be cleaned during the slip casting before the dry out.
5. Protective clothing should be worn where appropriate to ensure silica is not carried on clothing.

• Using clay tools and other equipment. -

1. Care should be taken using sharp clay tools to ensure the user or others are not harmed.
2. All clay equipment should be cleaned after use.