Hey guys, thanks for your kind words.
The junkpiles are pretty simple affairs. They are an assortment of model parts, film spools, old hacksaw blades, plastic sprues, etc. all hotglued on to a MDF base (which were cut in irregular curving 'pork chop' shapes). The perimeter ash/detritus is Liquitex gel medium (which you get at pretty much any craft store, I use the 'Resin Sand' type). Once the glue and gel has set you spray the whole works with black primer, making sure you get into all the crooks and crannies. Then take a big drybrush and do a HEAVY application of a rust colour of your choice over the works. Then do a lighter drybrush of a charcoal grey/black colour. Then highlight with a light grey. Done and dusted.
Hmm, that's a lie. I still need to add some bashed-up bricks to the junkpiles so they blend better with the groundwork of my figures. That will have to wait for a rainy day.
Anyway, I hope this helps!
Best,
Curt