MODULE CONSTRUCTION NOTES
Most of the articles that I have read regarding scenery construction have been about the permanent or semi-permanent type of model railroad layout. They start with a wooden framework, cover that with screen wire and then add two or more layers of hydrocal soaked gauze or paper towels to form the contoured terrain. The end result of this technique is often referred to as "hard shell". The molded hydrocal rocks can then be added to create some very spectacular scenery. However, this type of construction can be very heavy. Some time ago I helped move a 2 ft. X 6 ft. module that was constructed by these methods. It had four heavy, trunk style handles on it; two on each side. Two men could move that thing, but it was better with four men. Scenery is scenery but portable modules require a slightly different type of construction.
The N-Scale modelers here in the San Antonio area tend to choose styrofoam, cotton cheesecloth, paper mache and a very small amount of hydrocal when absolutely necessary. Although we use this type of scenery for modules, it could just as easily be used on permanent type layouts and in any scale. Our method of construction can be broken down into the following steps.
The general form is created by gluing down layers or pieces of either white bead styrofoam or the firmer blue or pink styrofoam. After the glue is dry, the styrofoam can be carved with a knife and worked with a rasp and/or sandpaper to the desired shape. The best glue we have found is Liquid Nails that is compatible with styrofoam. The next best glue is yellow carpenters glue, but this takes much longer (sometimes never) to set up. Both types of styrofoam are commonly used for home insulation and should be available at any of the building supply houses.
A variation of the above method is to use pieces of the bead foam to form ridges and high points. Pieces of corrugated cardboard and/or foam-core board may also be used as support pieces. Cover this loosely with a piece of cotton cheesecloth and secure the cloth to the wooden framework with hot-melt glue. The cloth should now sag or drape smoothly between the high points to form hills and valleys. There will be some shrinkage in later steps, so allow plenty of sag at this point.
The blue or pink foam
can be carved with more detail and sometimes directly painted to enhance the
detail. It can also be carefully etched or dissolved with Acetone or
similar type solvents to add a very realistic erosion effect.
For some reason it seems that a module is not complete without a bare rock outcropping or a rocky hillside. This is the place where we use molded hydrocal castings. For some people, it is the ONLY way to make rocks. Hydrocal does take stains very well and is the only way I know of to make the realistic looking hard limestone or granite rock facings. However, an exposed layer of soft marl or shale like rock is a different matter.
A couple of us have
used pieces of broken ceiling tile to create a soft, crumbly, layered type
of rock face. Ceiling tile is made from a paper-type material and requires
a good "seal" coat prior to painting. I use a water-based varnish that I
found in an art supply store. The brush must be heavily loaded and then
lightly touched to the broken surface with a straight in motion in order to
preserve the sharp, broken edges. A side-to-side brush stroke will yield a
rounded, water worn effect such as the rocky walls of a dry river bed.
Now our scenery begins to take shape. Most of us use latex paint for the "earth" coloring and we sometimes use the paint full strength when applying it directly to the foam or wood surfaces. However, the usual practice is to:
This Celluclay and paint mixture can be preserved for a few weeks by placing it in a sealed container (freezer weight Zip-lock bag) and storing it in the refrigerator. It does not sour (at least not with me), but it may form a couple of spots of mold that can be dipped off. I recently saw a suggestion to add a cap-full of Lysol Concentrate to each quart of a similar type mix to prevent mold growth. I added some Lysol in my latest Celluclay mix, but I cannot give a report on its long term effects yet.
NOTE: After the original writing of this article, I have stored this mixture as long as six months without any problems such as souring or molding. The mixture was then used for minor repairs of a module with excellent results.
The Celluclay must be thoroughly blended into the paint mixture to prevent little white clumps. An electric mixer is the ideal tool for this job and it can be easily cleaned. Believe me!
Some people prefer a variation of the mixing procedure. They start by crumbling the Celluclay into a dry mixing bowl and then adding just enough water to get the desired consistency. Color is then added as desired. This method is good for small areas, but it would be very hard to blend the color of two or three batches over a large area. The coloring agent may be latex house paint, latex artist colors or even water colors. Woodland Scenics has a selection of colors that are sold in powder form for adding to Hydrocal or Celluclay mixtures. The main thing for the "First Time User" to remember is to mix up very small quantities the first few times and to experiment.
I normally use the bead type foam and cover the form with a layer of cheese cloth. I then work the Celluclay mixture back and forth to get a thorough seal onto the foam base. In places where the cloth sags or bridges between two points, I apply the mixture a little thicker and work it well into the cloth.
Woodland Scenics has ground foam in just about any color and texture that you can think of to create your ground cover. I like to use four or five colors to get variations across an area. The ground cover is usually applied while the Celluclay paint mix is still wet. However, it may be necessary to lightly spray the surface with "wet water" between coats of ground cover. This will allow the paint mix to come up and hold everything together when it dries.
NOTE: Wet water is just plain tap water with two or three drops of liquid detergent added to break the surface tension and prevent the water from beading up on the surface of the module.
The final step is to
set the module to one side and give it time to dry. This may take anywhere
from 12 to 72 hours depending on temperature and humidity. Once the surface
is firm and dry, a person can add bushes, trees and other details as
I did not mention the steps required to color rocks because that is an art form in itself. The main purpose of this article is to describe the latex paint and Celluclay texture as applied to the styrofoam form. For those who have questions about rocks I would recommend the Woodland Scenics Scenery Manual. This booklet contains an excellent chapter on rock coloring methods using the paints and stains that are sold by Woodland Scenics.
I have seen two or three articles about scenery methods close to ours, but nothing exactly like it. One method is to use a mixture of Celluclay and hydrocal or plaster. The Hydrocal gives a firm surface for painting and the Celluclay provides texture to the surface. This is also the best surface for applying thin washes for adding color. However, the final surface is hard and somewhat artificial for my taste. Other methods call for Sculptamold, glue and other things that would create a hard and heavy shell. Our method yields a durable, flexible covering that even feels good to the touch.
Try it, you might like it ! ! !