Bentley Advanced Materials now offer Chavant NSP sulphur-free non-drying modelling clay on our web store. Chavant NSP is a great substitution for traditional plasteline when sculpting a piece for rubber moulding, as the sulphur present in these compounds can cause cure inhibition, especially with addition-cure (platinum) silicone.
NSP contains a high ratio of wax components giving it a stiffer, tough feeling which lends itself to accepting sharp detail lines cleanly. It is available in three hardness ratings: soft, medium, and hard. At mild elevated temperatures (45-50C) the clay becomes more malleable, and at 85C it can be melted and poured into a silicone or alginate mould.