The Backdrop

By Ty’s Model Railroad - 6/22/2011 08:37:00 PM

Plaster rock outcroppings attached to the face of a foamboard backdrop painted with trees, mountains and a blue sky

I originally cut the plywood backdrop to be in the shape of mountains but soon realized that it would be difficult and unrealistic to finish it this way. Instead, I decided to paint the mountains on one large backdrop. This way I could include the sky and have the backdrop extend further up to the ceiling.

Model railroad benchwork with unfinished plywood backdrop between plaster mountain structures in each corner

The first step was to build the rock outcroppings that extend out from the large and small mountains to the bridge. I only had about a 3/4" space between the track and the backdrop, so I had to make these rock outcroppings pretty thin.

Shallow, triangular homemade rock mold made from aluminum foil

I first traced the basic outline of the rock outcroppings directly onto the backdrop. I then traced paper templates and used those to start building plaster molds. I used aluminum foil to create the molds to the desired shape and depth.

Shallow, triangular homemade aluminum foil rock mold filled with plaster of Paris

I gently crinkled the foil and manipulated it with my fingers, ensuring that the grooves didn’t undercut into the plaster once I poured it. Before pouring the plaster, I coated the foil with 70% isopropyl alcohol to help the plaster settle. As soon as the plaster set, I removed it from the foil mold. This had to be done very carefully. The one castings did break as they are quite thin. Not a issue however as it was easily glued back together.

Shallow, triangular homemade plaster rock outcropping made from plaster of Paris

The blue Sharpie I traced the template with on the aluminum foil did transfer into the plaster in several areas. My recommendation would be to always draw on the OUTSIDE of your molds and not where the plaster is placed. Once the castings were completely dry, I glued the cracked sections together and verified how they fit on my layout.

Two homemade plaster rock outcroppings made from plaster of Paris with some blue marker on one edge

For the backdrop, I used large sheets of foam board which had white cardstock glued to each side. This provided a sturdy and workable surface. I made a large template out of scrap newsprint to get the correct shape I needed my backdrop to be, then traced it onto the foam board and cut it to shape.

Blank foamboard backdrop laying on a kitchen floor

I made a small sketch on paper of how I wanted the backdrop to look to make sure I had the correct look and feel. I then drew the basic locations of the mountains, tree lines, rock bluffs, etc. and got right to work painting. I used acrylic paints from the dollar store which worked great for this application.
Original sketch of a planned mountain background scene

I started with the sky, then the mountains, and last was the trees. I kept things as simple as possible for two reasons. First, I am not a professional when it comes to painting. Second, I did a lot of research on backdrops and found the more simple backdrops are usually more effective. This is because they tend to not distract from the detailed layout scenery.

A foamboard backdrop painted with trees, mountains, and a blue sky installed on a model railroad layout

Once the backdrop was dry, I fastened it to the original plywood backdrop with double-sided tape. I then glued the previously cast rock outcroppings directly to the new backdrop. Lastly, and used Poly-Filler to blend them into the rest of the layout.

A foamboard backdrop painted with trees, mountains, and a blue sky installed on a model railroad layout

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  1. Just a note to say nice work! Really impressed with your attention to detail on the layout and on your blog. Wish I could be half as detailed oriented!

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  3. Very nice. I just started doing my back drop. This gave me something to try. Thanks