I was going to mount the diorama just on a display board, but it looked a bit underwhelming – so I thought it would be worth experimenting with a more characterful base.
So, to make pyramid-esque stones – use a piece of insulation polystyrene (2.5 cm thick), and trace out a series of squares:
Begin to carve rock shapes:
I used a craft-knife for most of this work, along with a cocktail stick/sculpting tool here and there. The emery board was used to sand the polystyrene down where needed:
It’s best to turn the craft-knife blade sideways to make rough crevices:
When you’re happy with the polystyrene-carving, use a hot glue gun and attach it to the display board:
I also used pieces of wire to pin it, for extra stability – but this isn’t entirely necessary:
I shaped the foam slightly, to fit the shape of the desert-base:
Coat the polystyrene with either ready-mixed filler – or, as in this case, wood filler – which will give it a more realistic appearance, and make it harder-wearing; then add sand around the base of the rocks, using PVA:
If you intend to undercoat this with spray paint, then it’s important to give the polystyrene a wash with watery PVA; as the solvent in spray paint melts polystyrene. It’s also helpful to coat the sand likewise, as this makes it easier to paint:
I made a temporary mount, using some packaging foam/double-sided tape/masking tape to make it easier to hold while painting:
Basecoated – the red oxide paint was just dabbed in places which the sand hadn’t covered so well:
Ready to paint.