Hey Andy, thanks for the kind words.
the ground work is quite simple really, first i created a base layer using polyfilla (product used to patch up cracks in walls and stuff), with added pebbles
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note: the tank and the figure were only fixed to the base at the very end, when everything was painted and weathered.
then i taped the corners of the base with newspaper, creating a paper wall. I made a piece of plaster and broke it down into little pieces, some of it very very tiny (almost powder). applied a layer of wood glue to the base and i started to sprinkle the plaster debris in layers - allowing the glue to dry up and then applying a new layer etc.. i also mixed this up with splinters of balsa wood, and made a few small wall sections (carving tiny bricks in some of the plaster pieces)
when dry, it looks like this:
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then it's simply a matter of airbrush, washes and applying several colours of pigments.
I hope this answers your question.