Building a Bunker

This is what the finished bunker looks like. All the steps are detailed below...

I originally drew out the plans on graph-paper. I planned out the dimensions of the bunker itself and also how it would eventually fit into the rock formation.

The basic structure is constructed out of sturdy corrugated cardboard. The side walls are double thick. I wanted a removable top, so the main room has no ceiling. The outdoor section has no walls yet.

Here I added the low wall pieces for the outdoor section. I also glued in the floor material. The floor material is called Plastic Canvas and should be available in any well-stocked craft store. It cuts easily and gives floors the industrial steel grid look.

I lightly spray painted the basic structure black. I did this now to make sure I got all the recesses in the flooring black. It is important to due this before using any Styrofoam material, since the spray propellants will dissolve Styrofoam.

I then glued the structure to the bottom part of the terrain piece base. The bottom layer of the base is particle hardboard that I cut with a Dremel. I then glued a layer of Styrofoam to the wood.

I have glued on more layers of Styrofoam, "blocking" in the basic structure of the rock formation that I wanted to build the bunker into. You don't have to be very detailed with the Styrofoam at this stage.

When gluing Styrofoam, remember that many adhesives will dissolve Styrofoam. White glue, like Elmer's, does not dissolve it, but has another problem. White glue only dries completely with adequate ventilation, and Styrofoam is a great insulator. In-between large flat sheets, the white glue doesn't dry. I once broke open a terrain piece that was over a year old and discovered wet glue in-between Styrofoam sheets. I now use a special glue made for Styrofoam called Styroglue. For small pieces or for gluing cardboard to Styrofoam, I still use white glue.

I made a cardboard "square" that fits inside the walls of the bunker. This way the roof will fit securely. I then glued this into grooves carved into a sheet of Styrofoam.

Taking a fireplace lighter, I melted the Styrofoam into a more natural, rocky shape. DO THIS ONLY WITH LOTS OF VENTILATION! Melting Styrofoam releases toxic fumes, but creates a great erosion effect. Because the Styrofoam is built up in layers, you will get areas where the layers melt apart or don't melt as much as the rest. Use a fireplace lighter and not a standard pocket lighter since the pocket lighter quickly get to hot and will melt, or worse, possibly even explode with extended use. A candle can also be used, but is harder too control, and the dirtier, sootier flame a candle generates actually melts Styrofoam differently (in my experience, it creates more of a lava rock look).

After you are done melting it (and letting it cool), clean up the shape by tearing away and smoothing out whatever doesn't look right. Pay particular attention to where layers of Styrofoam meet.

Once all this was done, I used premixed wall filler compound to do the final smoothing and detailing of the "rock". Pay special attention to the areas that you had to tear away just before this and to the seams between layers of Styrofoam. If the seams are not smoothed out, they will really stand out once you paint the terrain piece. Get dirty and use your fingers to smooth the filler compound onto the Styrofoam. Using more filler creates can create either a rougher rock hewn look, or with even more filler, a soft, sand worn finish. Using less filler results in a more water-eroded look.

I did all of the melting with the top on so that I could make the two pieces line up visually. Here is a picture with the top removed.
Here is a close up of the rock texturing before any paint is applied. I also used filler compound to fill in any exposed corrugation from the cardboard.

I glued on fine aquarium sand to the top of all rock surfaces. You'll notice the top areas of rock are flat and smooth because I did not melt the top. While this is not as realistic, it is a gaming consideration. I'll want to be able to place figures on these surfaces, so I left them flat.

I also glued flat plastic strips to the top of the bunker walls on the outside area and glued a corrugated-textured piece of sheet plastic into the doorways.

I glued 3mm Westrim Half-Round beads to the top of the external walls and to some of the edges of the bunker. These make fantastic rivets and are cheap. These should also be available in craft stores.

I painted a dark brown wash over everything except the bunker itself. The bunker I brush painted black again. I also brushed a thin black wash over some of the rocky areas to darken them (especially into crevices).

I dry-brshed everything except the sandy areas gray.
I dry-brushed the sand an ochre/dun color. The bunker has been dry-brushed with additional, lighter shades of gray. The rock has been given a very thin brown wash (mostly because I used a far too light gray on the rock in the last step).
The bunker has been given a thin black wash to emphasize the details. The rock has been dry-brushed with a clay-like red-brown color.
The bunker was given a much softer dry-brushing of gray to create a concrete look. The rock has been dry-brushed with tan paint and the sand was dry-brushed with an even lighter tan color (called Sandstone in the brand I used).
Another look with nothing additional done. This view is of the back bunker door. At this point the piece is basically done. You can add additional details now, such as graffiti or additional weathering.