And the dirt is done! I think...
As I said in the last update I had to build up the ground a bit under one of the rear feet so I did that with some foam and plaster/dirt mix. Then following the instructions in the "groundwork" PDF I linked to earlier I taped up the black areas of the base and did a final coat of dirt, gel medium and pigment over the top of the plaster/dirt mix. This is by far the best technique to use, although it would have worked better if I had some super fine dirt in the mix as well. Overall though the final result looks good and feels pretty solid. Oh and the tape is definitely necessary as this final dirt/acrylic mix tends to get everywhere. I used 10mm Tamiya tape due to its general awesomeness, particularly for this kind of application.
The bottom of the feet and Tau figures were both sprayed with mould release before they were seated into the still wet final sand mix. This would ensure that I could actually remove them again for painting without breaking up all of the ground around them.
After the groundwork had dried for 48 hours I then attacked it with the airbrush and various mixes of sand and brown Vallejo model colour paints thinned with clear Windex. Works a treat! Any random rocks and the cliff face were sprayed with a lot of grey added to the mix to give them some contrast (even if that might be less realistic). Unfortunately I forgot to mask off the cliff face when I was spraying the black on the sides of the base, so the paint has ended up too thick in a few spots near the sides, which is unfortunate.
So here's how it's looking now. Next step is to apply the Mininatur grass tufts around the place. I had planned to dust some pigments around too (I've got a bunch of Secret Weapon ones), but some experiments with them during airbrushing proved pretty disastrous. The main problem is that I don't have any that match the tones I've airbrushed with properly, so maybe I just have to source an appropriate pigment...
The SAW itself has been receiving attention too. The holes in the hips where the pins were mounted have been filled with putty and sanded smooth. The larger gaps in the hip ball joints were puttied up also. I dare say that the next step will be priming! However that will have to wait until I've finished cleaning up the chassis so it can all be primed in one go. The beauty of the method I've used to fix the legs to the base is that it's really quick and easy to remove for painting (I had it removed while painting the base).
Air brushing the base was really good practice for when I'm ready to do the SAW itself. I've been using the airbrush for priming and stuff like that, but nothing that required fine control of the colours. I'm pretty confident that I'm now ready to do the big model!