I’m attempting to build a bridge in 1/35 scale, consisting of two stone arches and a roadway big enough for roughly two lanes of traffic. I imagine that it was built in the Vosges mountains, some time before roads were primarily automobile thoroughfares. So even for two lanes it’s slightly narrow.
I plan on blowing out one of the arches, so I can depict a temporary roadway replacement using a set of 1/35 military engineering treadway pieces. The whole scene will represent the U.S. Army in Eastern France, in 1944, and I’ll probably have vehicles of the 522nd Field Artillery Battalion crossing. (These were a segregated Japanese-American unit, part of the famous 422nd Regimental Combat Team.)
The bridge is constructed of layered XPS insulation foam. All preliminary drawing was done on cheap craft paper with a ruler, pencil, and small paint can for the arches. I then used the craft paper diagram to mark out points on the foam for shaping. I used a cheap hot-wire carver, an Olfa utility knife, and rough sandpaper to shape it. The angles and dimensions aren’t precise, but neither are those of many real stone bridges, either.
This was my first time attempting to carve a stone pattern into XPS foam, and so far I find dragging a dull pencil tip through the foam the best method. It’s fast enough, and leads to less tearing of the foam’s surface. It might also help a bit to sand the foam surface rough beforehand. Using a rounded, blunt piece of dowel, I trace over the carved pattern to round off the faces of the stone a bit more. The whole process takes a long time, but is fun to do.
I paint diluted spackle on over the stone pattern, for texture. So far, I’ve carved and coated the arch interiors, and carved the insides of the parapet and one side of the bridge. I need to carve the other side.
A 1/35(ish) toy Trabant provides a sense of scale.