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The next phase is the tinting of the mould. The artificial rock surface will look
more natural if the deep spots are darker than the protruding ones. Take
some black dye powder on a ball of paper or piece of sponge and wipe
along the surface of the mould so that the black dye sticks on the high
points. Then they will be in the dents as the mould is a “negative” of the
original.
Tint the ridges of the mould by
dabbing black dye powder along
the surface. These will be dark
crevices in the final product.
Now you can start with the first layer of plaster. Make a mixture of Sika
plaster, approximately 1 part liquid and 4 parts plaster powder, that can be
stroked with brush. You can find the right consistency by experimenting. The
mixture should be quite thick. If it?s too thin, it cracks easily when it dries. If
it?s too thick, it can be difficult to paint on.
When making the mixture, add the dye powder as well - brown, terracotta or
whatever you prefer. The easiest tool for mixing small portions is a regular
whisk, stolen from the kitchen drawer.
Stroke an even layer of plaster all over the mould and let it dry for about 24
hours before applying the next layer.
Stroke an even layer of plaster all
over the mould and let it dry 24 hrs.
After the second layer has dried for about 24
hours you can start finishing the object with the
lacquer.
I have done this with the previously mentioned
lacquer. The lacquer is made of two components, a basic agent and a hardening agent. It
is completely harmless when dry and a little
elastic too, as is Sika Top Seal 107. Take two parts of lacquer, one part of
hardening agent and a small amount of TIX 150 thickening agent and mix
carefully. A small amount works out at about a tablespoon for 2 dl of lacquer.
Mix moderate amounts at a time and very carefully. If it is not mixed well,
part of the lacquer may not harden.