Cement or stone structure

[Cklasse]

I am working on my Lynx helicopter 

and it’s about time I build a structure at this stage. I know nothing on diorama making but would certainly want to do it for all my models, at least a decent base. 
Can someone kindly suggest how can I make this cement structure? 
I am thinking of building a shell of this structure with foam but not sure what material can I use to coat the outer surface to achieve that “Stone” effect.

Edited September 28, 2022 by Cklasse

[Crayons]

3 hours ago, Cklasse said:

I am working on my Lynx helicopter 

and it’s about time I build a structure at this stage. I know nothing on diorama making but would certainly want to do it for all my models, at least a decent base. 
Can someone kindly suggest how can I make this cement structure? 
I am thinking of building a shell of this structure with foam but not sure what material can I use to coat the outer surface to achieve that “Stone” effect.
 

 

You could try a mix of mod podge, plaster/grout, water and a squirt of the basic colour of choice. Mix it into a paste and trowel it on.

[Black Knight]

Pollyfilla, or the equivalent in your area. Home DIY repair ready-mixed plaster

[speedy]

As above with plaster, but for the scale effect use a cube of sponge and dab it. You’ll use all 4 sides as it will clag up, so make sure you have some more available. The painting will make it though🙏

[voozet]

The shape is quite simples. Use foam as a mold. Fill it with plaster of paris. Once out of the mold, texture with a metal bristle brush. Horizontal "steps" can be easy made in plaster, for example, with a file or knive (this seems easier than cutting them in foam/mold).

Recently I was making plaster diorama elements for my model, a little more detailed description:

https://www.britmodeller.com/forums/index.php?/topic/235099759-135-ian-mcques-remora-flying-boat-scratch-build/page/9/#comment-4500602

 

However, if you prefer to cover the foam with a layer of texture, you can use this.

This is, say, instant concrete, ready to use.

 

 

Edited October 1, 2022 by voozet
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[Cklasse]

Just an update to what I have build for this cement stone structure. I had used gritty plaster, mod podge on plastic sheets.