This is a past work. I'm posting it for record-keeping purposes. Created in September 2019.
I didn't do any special modifications, just tried my best to make it look weathered. However, I didn't apply a top coat. I rubbed a Real Touch Marker with a melamine sponge to give it a semi-matte finish.
I used a photo panel bought from a 100-yen store, paper clay for the base, cork board for the steps, and zeolite (the kind used in aquariums) to attach the pieces with water-soluble wood glue.
The paint used is water-based paint.

Maganac | ガッキー's Gunpla works