Liquid poly - get a bottle of "liquid cement" ... the brush on glue made for polystyrene model kits (actually a solvent - brush it on and it melts the surface of the kit part, put the bits together and as the solvent evaporates the bits are glued together) ... drop small bits of the sprue the kit comes attached to into the bottle until it is a semi-liquid gloop of the desired thickness.
When applied to a model the "liquid poly" builds a thin surface of styrene as the solven evaporates. This surface can be built up in layers if needed.
Easy peasy!
When applied to a model the "liquid poly" builds a thin surface of styrene as the solven evaporates. This surface can be built up in layers if needed.
Easy peasy!