Monday, April 18, 2011

Decoy-duck the moulds

Moulds for the decoy duck

The next stage is mould-making.
This is a complex process, especially when you intend to slip cast the products instead of press-moulding. For a detailed and visual account of my mould making technique - follow the link. Slip-cast moulds are very different, because the thickness of the mould assists the slip-casting process. The dry moulds absorbing the water out of the slip. The moulds therefore have to be thicker than moulds for press-moulding, and more importantly, you need to ensure that most of the detail is captured in the mould. The thickness of the mould (in large sculptures) make the moulds very heavy, and separating the multiple piece moulds during the  slip-cast process, to remove the fragile slip product, can be tricky. Splitting a complex prototype such as the decoy-duck into various pieces requires experience. Various options should be considered to ensure less split lines, taking into account the best option to release the prototype from the mould and more importantly safeguarding the release of the fragile slip cast product. Press-moulding moulds are normally much thinner and reserved for sculptures that are much larger and as mentioned in a previous blog post, you don’t require as much detail at the prototype stage.
Prototype within the mould.
 These moulds were made for me by one of my students, Kenny Sonono, he successfully completed a B Tech in Ceramic Design in 2009 and graduated last year. I was under pressure to get the moulds done a.s.a.p. as the animator is starting the development of the projected animation next week. The moulds will have to be quick dried in the kiln over the next two to three days, set on soak at 40 degrees Celsius (max 55 degrees Celsius).
Close-up of decoy-duck torso in the mould.

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