Building Structures with Foam Core
For a long time now, I've been using a material known as foamcore, sometimes called foam board. Some of the applications
on my layout are scratchbuilt structures, walls and concrete objects such as slabs and steps. I'll discuss these uses and
hopefully you'll be able to see the versatility of foam core as we go.
Foamcore usually comes in 30" X 40" sheets, but other sizes are also available. Foamcore is easily obtainable at most arts
and crafts oriented stores as well as office supply stores. I checked out the foamcore that Staples offers. Beside the 30" X 40"
size, they had some smaller sheets for sale as well. They come in some colors like red and green as well as the standard
white. For a little bit more money, they also have foamcore that was black inside and out, that could become roof material. The
foamcore retailed for $2.97 per colored sheet or 11.99 for three 30" X 40" sheets of white, which should cover a multitude of
structures. They had a sheet for $2.97 that was called "sand". It would make a great looking floor for some structures.
The standard thickness is 3/16ths of an inch. This would make a wall of 1 foot thick in S scale. I used the chart at the Plastruct
web site and came up with a thickness of 1.4 feet for HO and .75 feet for O scale. N scalers might not like using something
that thick, but they can be the judge of that.
You do need a sharp blade for your Xacto knife or utility knife. I went through more than one blade when I did skyscrapers for
my layout, but for smaller projects, one sharp blade should do OK. A dull knife edge will result in ragged cuts. When doing
roofs, you can hold your knife at an angle to make the rood sides butt together snugly.
For bricks or roof shingles, I've developed a technique for producing brick paper. You need a good "screen grabber" that
captures images right off the computer monitor and stores them in formats like .JPG. I use a product called "Capture by
George". I look for images on the internet of bricks and other building materials. A good site for this is at:
mayang.com/textures. For our project, I went there and selected a nice looking brick pattern. Then I bracketed a section of it
that looked consistent with "George" and saved it in a file. You have to be careful to keep the image very generic and not have
any inconsistencies. I'll explain that later.
Now you go to a word processor like MS word. Select a new document and use the insert from a file command to get the brick
file you just created. Then go to the Page Setup and decrease the margins for left, right and top to .4 inches and the bottom to
.5 inches. This will fill the page with more bricks. If your image is less that one page, you can simply keep importing the same
image in order to replicate it and fill up a page. Since Word lets you resize images, you can enlarge the bricks or reduce them
to get the proper size for your scale. Here is where the necessary consistency comes in. If you have color shifts or specific
patterns in the bricks, they will be replicated if you use several copies of the image on one page. It may take a little trial and
error, but once you have it and save the results, you don't have to go through the process each time you produce the brick
paper. Of course, you can use commercially available brick paper or peel-and-stick bricks as well. There's a huge variety of
bricks, stones and roof shingles on the internet to choose from.
Our project is a simple one. It will be a small office or back shop that can be used within an industrial complex. It has an
entrance door, a freight door and several small windows. As we go, I hope to show how easily foam core can be used to
create a decent looking structure. I didn't include any measurements except for the roof we're using so that the article would
not be scale specific and just include general tips for using foamcore.
Figure 1 -
I bought a used plastic HO roof at a NMRA regional convention for a buck with the intent of putting a building under it that was
suitable for my scale. S is only 136% of HO, so many HO structures and parts of structures are usable for S. Here the two side
walls and the floor are drawn. I painted some Grandt Line windows white as well as a brown freight door. The windows to be
cut out have been traced around the plastic windows.
Figure 2 -
Here the two ends are drawn and the windows and doors to be placed in the ends are shown. We now have our main
Figure 3 -
The basic tools for the foamcore part of the project. The ruler and pencil are for drawing the lines on the foamcore. Foamcore
takes white glue very well. The airplane glue is for keeping the windows in place when we insert them.
Figure 4 -
Here are two sheets of brick paper that I produced with the instructions mentioned above. These were adequate for our project.
Figure 5 -
The parts have been cut from the foamcore. The freight door will be in the closed position which didn't require any cut out.
Figure 6 -
The brick paper has been measured, cut and pasted to one of the ends. I use white glue spread very thin so as not to raise
creases or bubbles. I allowed a slight overlap at the sides to allow for the 3/16"s thickness of the foamcore. I held the side up
to a light to see the windows and cut a diagonal "X" where the windows will be.
Figure 7 -
By pushing the paper into the window and gluing it, you can get a clean edge and ensure a good fit for the plastic windows.
Figure 8 - The windows and door have been pushed into the cutouts and airplane glue applied to the backs. If the fit is too
tight, the foamcore will give in to some slight pressure with a flat edge or your finger.
Figures 9 & 10 -
We added some extra detail to the windows. For the extra row of bricks above the windows, we white glued a strip of the brick
paper on to a piece of stripwood. Below the windows is strip wood that was painted white. I used white acrylic from a tube.
Figures 11 & 12 -
The sides have been attached to the floor and each other with white glue. I use masking tape to hold them in place. The tape
will separate from the brick paper without harming it when pulled gently.
Figures 15-16 -
Here's the completed structure. I added a gutter and downspouts and a facia at the roofline. I made some steps from leftover
foamcore. I also wrapped some brick paper around the chimney that came with the roof and glued it with airplane glue.
Figure 17 -
Here's the model sitting on the layout. I haven't decided on a permanent location yet. The entire project took just about 8 hours
to do and I hope that I showed some of the benefits of using foamcore for your structures,
These structures were constructed with foamcore. I wanted to show that it can be used for more complicated projects. The
Wadel Furniture Co. was inspired by an article in the October 1979 Model Railroader and the Heffner Building Supplies was
based on a December 1984 article in Railroad Model Craftsman.