by blind pig » Fri Nov 05, 2010 10:50 pm
As a further note on clays used in modelling and casting, I have been told by the lovely people at Barnes, that Plasticine brand clay is no good for modelling as it contains sulphur which will inhibit the curing of RTV Silicones, such as Ultrasil.
Make sure that whatever you use does not contain sulphur.