Moderator's note; Here's an excellent "how to" that I've copied from RJR's layout thread:-

In answer to the question how I do the rocks. :-

It becomes obvious how the shapes appear when you see how they are done !!

I mentioned I insulated the shed with 1" styrene, well while I was cleaning up the offcuts the pile started to look like a rock face !!!

So I took the idea further, stack of polystyrene strips stuck together with the polystyrene cement. Then the problem of a surface finish came up. The styrene ball effect did nothing for me. The answer came in the form of a bucket that I had mixed ceramic tile adhesive in ( the powdered form) It had a look of rock. So I mixed some up an painted it on with a sttiff brush.



When dried it look a bit flat and boring, this is improved by the use of a product available from B&Q in spray can. It is a decrative finisih made by Plasticote called flecspray and is available in several colours. I had previously used it on my outdoor layout as ballast. The colour I used for the rock is Gothic Grey and gives the speckled finish..



Finally it still looks a bit uniform so my favourite colour Matt Black is sprayed on from another aerosol in a fine patchy finish.



Last job add grass scatter to taste.

This larger area that forms the tunnel at the back of the shed was done in the same way but a piece of ply was built into the pile of polystyrene to add strength.



The grass is dropped from above if it finds an area flat enough to settle on fine if not you get expossed rock





I use 2 colours of grass just to give a patchy non uniform appearance.
I hope this helps and answers the question.

Wow that's fantastic. I currently have no plans for a rocky outcrop on Devon Junction but if I had then I think I'd be using this method - what a winner. :D  :D

Les

I like it  :)

Superb - I can see my layout having lots of rocks !!!  

Petermac

Glad you like it, One of the plus sides of doing hills this way is you can always carve some out at a later date then just patch the exposed styrene with a bit more tile adhesive.

If you want an even quicker way of making hills …..

When I had the outdoor layout I needed waterproof scenery, in to the back of the van and out came some expanding foam in a can !!! Such as "No more big Gaps"

Squirt it where you want it



Let it set expand and set (about an hour) Then hack at it with a bread knife, to loose the round baloon shapes. Finally spray with car spray aerosols in a couple of colors, this is chocolate brown and black.



John
RJR

Thanks for the demo, John.
I know that MikeC has used this type of foam, so it's nice to see a few shots of it in use.

Hi - the wonders of forums like this.. I followed your method and this is the result. many thanks Craig ;-)







 

A great reusult there craig it has come out extremely well this method i may consider doing myelf.

cheers Brian

lloks great, glad it worked for you ! I like the short lower level platform !!! It gives me an idea !!!!!!!!!!!

Not planning a third loop of the garage are you John!

John will be digging out the floor like Brian soon, if he keeps going he will meet all our friends from down under