Adding Rock Castings to the South Branch of the Arkansas River Model 9FEB14

Cutting Mountains in Minutes Castings

Mountains in Minutes castings are still available in some places, like Gilbert's Hobbies in Gettysburg, Pennsylvania. They are getting a little hard to come by, but an internet search turned up the Flexi-Rock castings that used to be made by I.S.L.E. Laboratories are now offered by Scenic Express. I like these castings. They are good generic rocks that can be cut apart or used in big pieces to create mountain details. The "Royal Gorge" casting is excellent for use on Colorado model railroads.

Coping with Cutting

I usually use a coping saw to cut out the sections that I would like to use. A coping saw allows me to do an accurate cut without too much effort. It is a flexible and inexpensive tool.

With a long cutting surface the blade can be turned in different directions to cut out the pieces. There is very little waste and the Mountains in Minutes castings are roughed out. The castings still need to be trimmed for an exact fit.

Making Room for the Castings

An X-Acto #5 knife is a good tool for cutting and shaping the styrofoam, especially with a chisel blade. The large handle of the #5 knife allows the pressure necessary to affect the cuts.

When fitting the Mountains in Minutes castings, some sanding will probably need to be done, especially if you are lining the edges of a mountain stream. I use 3-M sanding blocks for a lot of this kind of work. They come in different grits and it is good to have several on hand for model railroad projects. I hold the sanding block with one on the table and rub the bottom of the casting across the block. This will give a level bottom. It does not have to be perfect. The bank will be filled in with Arizona Rock and Mineral sand and gravel material, so the edges just need to be somewhat level. 

Checking How the Castings Go Together

I check the size as I go to ensure that the castings will fit well and not obstruct the train movement.

I interlocked the pieces and test fit them. I played with placing some of the extra castings on the outside of the curved roadbed to see what the river course would look like. Notice that - as on real streams- the watercourse broadens as it leaves the confines of the canyon. In this case, this add to the apparent length of the stream with the converging lines of forced perspective.

The Renaissance Tool of Perspective

Imagine a vanishing point about a foot past where stream turns to come out of the canyon. This is where the converging lines of the river bank would meet. This is a tool of the artist who paints on canvas to give the appearance of depth to a scene. Since a modeler can work with three dimensions in space, using forced perspective creates an additional illusion of a deeper scene. 

This overhead shot shows the process of putting together the elements of the canyon and the railroad so that they will work together to draw the viewer into the illusion. Next steps including adding a grade to the stream up the canyon and working with various materials to smooth the bottom and edges of the stream.