Tall rock formation terrain

With  the new large models for 40K I wanted to add some larger terrain pieces, or should I say taller to block line of sight.  One most easy terrain pieces to make is to make a hill or a rock formation, so I started to search for tall rock formation and I really like the ones you could find  around Li river in china. They are tall and not that wide so it makes a good good inspiration for my terrain.

I did two pieces of rock formation terrain, One with a "hill" base and one that has a narrow base, plus a small piece that I made of the left overs from the taller ones.

Materials;

• Styrofoam (the really cheap one you get whet buying electronics)
• PVA glue
• Wall filler
• Fine sandpaper
• Pen
• Serrated knife
• Cardboard
• Paints (I used; Black, white, Maroon and Burnt umber)
• Static grass
• Small gravel 
• Matt varnish spray

I started to glue together pieces of styrofoam to get the height and  rough shape of the rock formation, after the glue has dried I cut out the shape of the rock formation (you could draw  lines to follow when cutting out the shape),  the shape can look really flat at this point. To remove the flatness I used fine sandpaper to smooth edges and to give the rock formation a more round shape. This is really messy when using cheap styrofoam, you will have small styrofoam beads all over the place. You could use insulation styrofoam that isn't made up by small beads, its easier to work with and don't leave your work area looking like a snow landscape.

After that is done I put the styrofoam on the card board to cut out the shape for the base, draw, cut and glue the styrofoam to the cardboard. My bases are I little larger then the rock formation, this is for protecting the edges of the terrain from chipping.

Now use the wall filler, I put it on the styrofoam with my fingers for better control of the pattern/shape it will get when dried.
The wall fillers job is to give  a rough surface, this will help with the painting and the general look of the terrain. If you paint over the styrofoam without anything hiding it you will see the styrofoam beads and it wont look as good.
Let the filler at least dry over night, when its dry I run my hands over the surface to remove the "high edges", otherwise these edges will fall off when handling the terrain and you will have to repair it, which is never that fun.

Now put some glue where you think small rocks should have landed when falling off the rock formation and then put the small gravel on the glue and let it dry.

Painting, you can put on a indoor wall paint to cover the terrain so the filler don't absorb your acrylic paint. I didn't do it this time because my acrylic paints are a really cheap brand I bought  in large bottles, but if you use model paints (I don't recommend this) I would use the wall colour before painting the terrain with the model colour, I usually use a white colour for this.

Rock painting; I tried different shades of grey, I added some brown to get a little warmer grey then when only using black and white. You have to decide if you want dark or light grey rocks or perhaps a more beige coloured rocks, I went with light grey rocks in the end.
When painting put on the darkest shade of first all over the terrain, then dry brush several layers, I went with one base coat and three dry brushing layers and the last layer was a light dry brushing layer of pure white.
I painted the areas where I wanted  put static grass maroon, this is for when static grass falls of because wearing it will look more like dirt below the grass.

When applying static grass (use a newspaper so you can get the excess static grass back in the container, don't waste it) put the glue on the area first, you can delude the glue with water so it wont dry  as fast and then sprinkle generously over the glue and pat it a little before you turn it over and pat it again to remove the excess static grass.
After the glue as dried I apply  allot of matt varnish all over the rock formation to seal the static grass, there is other ways to do it, such as using a glue/water combination and spraying the terrain with it, then your done.

Here's the result;