In this video Martin Tarnrot demonstrates his method of making HO scale roads, and in particular, gravel roads. There are many methods to achieve a nice looking result, but the method he has used throughout my entire layout. For this video instruction, Martin made a small diagram, made from two inch thick Styrofoam. He prefers to make the road itself from thin Styrofoam, styrofoam strips used on the modern wooden floor to be specific and can be found at the floor section of a DIY shop.
However, sometimes modelers may have problems obtaining this styrofoam, so tape can be used instead. He uses a razor blade or hobby knife to cut strips from paper tape. These two strips of tape will mark the position of the road, but will also help make a straight line when plastering over it later.
The plaster he uses is a medium, coarse sand based water based, plaster for indoor use. Both Woodland Scenic, Noch, and the other manufacturers have landscape plaster which also can be used, so long as it’s water based and easy to sand. If a modeler wants the road to go up or down, then they can cut the road surface from the baseboard, and reduce the thickness of the road. With this thickness, it will be much easier to shape and then glue in place in the desired position.
Before gluing it in place, however, it must be sanded very smooth. For this Martin uses a sanding block and sanding paper. Once the surface is very smooth, it’s time to glue it in place on your baseboard or layout. Once this is left to dry properly it is time to shape the ground on both sides of the road.