Thanks a lot! When i put it in i thought i missed the over the top, comic approach of the mountain depicted on the plastics, but the more i look at it the better i like it. The realistic approach indeed blends in with the chrome and steel colors of the supercharger very well.
I mainly used these 4 colors, basic waterbased acrylics.
First step is to prime the whole thing to get rid of the original color and to prepare it for taking the colors. I used a spray on fine surface primer for plastic & metal.
When the primer was dry i coated the whole thing in an earth kind of color, a mix of raw umber and mars black. Let this coat dry and then started to drybrush with a greyish color (white & black). Really went crazy here until it did look like a rocky surface.
Snow is mostly white with a tiny drop of a light blue color. Applied heavily on top surface, drybrushed on steeper areas where snow could not pile up and would be blown away from winds.
The tunnel entrance was done in a reddish mix of burnt siena and a little raw umber.
Last step was a dark wash with a heavily diluted black color to darken the cracks and crevaces.
Nice youtube video for inspiration, just look for model railroad landscaping
Now i quit talking because i start sounding awfully lot like Bob Ross