Making castings

Recently, I have started making resin castings of some of my stone sculptures. The originals are above in these pictures and the casts below. I choose pieces with simple, flattish shapes, so I can make my own molds: making them for complex forms is a speciallist job. 

I thought this would be a quick and easy way of adding to my work, but in practice each copy is almost as time-consuming as the original carving

First step : making a mold

I make a waterproof wooden barrier around the carving and coat it with a molding rubber compound. This is the mold for 'Three Dolphins' (the original is top left  above), still in place on the scultpture (left). I then cast some builders' plaster on top, to provide a base for the floppy rubber mold when I do the casting (see later picture). I then remove the mold from the sculpture  (right)

Next step: casting

With the mold back in its wooden surround and on its plaster base, I paint a 50:50 mix of polyester resin and a metal powder, such as bronze, inside the mold, to a depth of a few mm. (left). Once set, I add a thicker layer of resin mixed with a  filler such as  slate powder (right). This forms a very durable shell which I fill with plaster and let it set (far right - you can also see the cast's plaster base here).


Last step: polishing and patination

I seal the bottom of the sculpture with a final layer of resin and then remove it carefully from the mold. At this stage, it is a dull uniform colour (left), but polishing with wire wool brings up the highlights, and  various chemicals are applied to add colour, such as darkening or verdigris.