Decide on the break-line.
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This illustrates the two ways of splitting a mould. The apple would be divided around the equator. Otherwise the recesses at the stalk and blossom end would create undercuts. The banana would be divided with the break-line going from north to south, otherwise the bend around the stalk end would create an awkward draw. |
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Draw a straight line along the length with a spirit-based marking pen which won't wash off. Choose the highest ridge on the stalk side. |
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It might seem quite simple to draw the second line on a banana, but this diagram shows that the second line will not necessarily be exactly on the opposite side, but on the highest point on the opposite side. |
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The finished plaster mould will be filled with clay casting slip. The stalk end of a banana is the obvious place through which to fill and empty the mould. For a piece the size of a (real) banana, the thickness of the slip should be one eighth of an inch. (These small measurements are easier in millimetres, so I will use mm. from now on.) The slip should be 3 mm. thick. It needs a hole of at least twice this to enable it to pour out. The stalk end will have to be built up with extra clay to at least 12 mm. so that the filling hole remains open after 3mm. thickness of slip has built up on the inside of the dry mould. |
The next page is embedding the model.