@SLK posted his results with using 3d printed parts to create molds and resin casts. That prompted me to post up my own results. I also used prints to make RTV molds and then those molds to cast plaster copies
The model is of a Coke Oven face in 1:48. It consists of two columns and a large and small arch. The base is a piece of Sintra (PVC foam board) .. everything is glued together with epoxy.
I made a mold box and epoxied the model to it ..
I used Smooth On's 'oomoo 25' RTV. The only thing I would do different would be to use a brush to make sure the RTV was pushed into every crevice. Just pouring on did get 'almost' into every detail. One of the plaster castings in in the lower left
Close up of the cast piece
This is a test-piece I used to experiment with coloring. Since the brick in a coke oven like this would have been hard used, grimy etc. .. I sprayed some AI (Alcohol India Ink ) wash on, let that dry and then dry-brushed some FolkArt Terra Cotta acrylic
Plaster is something I picked up at Hobby Lobby . something called "Pottery Plaster - for use in ceramics" .. it's harder then plaster of paris at least. If I had a choice would use Hydro-Cal .. but that's a pain to get my hands on.Ed Traxler, MicroMimesis.com