How To Make Model Railway Hills From Mod Roc or Plaster Bandage

Creating hills and embankments using plaster bandage (or Mod Roc) is one of the most tried and tested methods. It's low-cost, quick, and easy… Just be prepared to get a little messy!

All of the materials we use in this tutorial can be recycled from your household waste (cardboard/brown paper) or obtained for a minimal cost from our online shop, or your local model/craft shops. Many of the scenic detailing materials like static grass and foliage, you'll probably have in your modelling material stores already.

Materials you'll need to make a hill or embankment:

• Plaster bandage or Mod Roc
• Scissors
• Plastic wrap
• Bowl of warm water
• Optional: newspaper, cardboard, embankment formers or other materials to shape the base of the hill/embankment
• Earth-coloured emulsion paints
• Acrylic paints
• Static Grass - assorted colours
• Flower tufts
• Gravel for boulders & rocks

Step 1: Prepare the basic terrain

Firstly, of course, we need to decide where the embankment or hill is going to be sited on our baseboard. Then we need to make a “sub-structure” to support the plaster bandage while it sets. This can be done using a number of methods. For small hills and simple sloping terrain, crumpled-up newspaper or brown kraft paper (waste packaging) is ideal. Simply crumple it up in your hands and form the basic shape. Then tape it down to the baseboard using masking tape.

For larger hills, use old cardboard boxes cut into chunks to form a lattice structure. Cut slots in the cardboard, and slot various assorted shapes together. Trim to shape with a craft knife or sharp scissors to get the basic desired shape.

For something a little more durable, wooden embankment formers such as our BB026, BB027 & BB028 can be used to form a super-sturdy, durable base that will really stand the test of time. They don't need to be glued together but you can glue them if you wish. Then secure them to the baseboard using masking tape of PVA glue. Fill in the spaces between the formers using crumpled-up newspaper if necessary to support the plaster bandage and prevent any uniform sagging.

Step 2: Cut the plaster bandage 

Using scissors, cut the plaster bandage into strips or pieces. The exact size will vary depending on the shape of your hill. For a long embankment, strips up to 1m long will work well. For a curved hill or railway cutting you'll need to work with shorter lengths so you can work them around the curve and work them into the contours.

Step 3: Soak the plaster bandage

Dip the plaster bandage pieces into the bowl or bucket of warm water, making sure to completely saturate them for a few seconds. Hold the end in one hand then using the other hand “stroke” off the excess water, smoothing the plaster gently along the bandage. Soak the pieces one at a time, not all at once!

Step 4: Apply the plaster bandage to the hill

Lay the saturated plaster bandage lengths onto the base of the hill or embankment, overlapping them slightly to create a solid structure, smoothing them down with your hands. While the bandage is wet, take the opportunity to add any extra details such as dips and raised sections by poking and pulling the plaster with your fingers.

Step 5: Add extra layers for strength

Once the first layer of plaster bandage is in place, let it dry for a few hours before applying another layer. You can speed up the drying process using a hair dryer. Add any extra features such as vertical rock faces etc as you go using more crumpled-up paper etc.

Step 6: Shape and texture the plaster

After the final layer of plaster bandage has dried completely, you can shape further using decorating filler or similar to sculpt any additional sections of an exposed rock face or any prominent features that couldn't be shaped using the bandage. Use a hobby knife or sandpaper to carve out small details. Stiff wire brushes are also useful for texturing rock faces.

Step 7: Paint with earth and rock paints

Paint the plaster bandage with an earth-shade acrylic or emulsion paint. Tester pots from your local DIY centre are perfect for the job and provide an excellent base for static grass & foliage.

Rock faces should be painted in a suitable shade representing the basic colours of rocky outcrops in the area you're modelling. So you'll need to choose the right shades of grey or brown to match your local stone, e.g. granite, limestone etc.

Step 8: Detail the rock faces

Detail exposed rock faces by dry brushing other lighter and darker shades of acrylic emulsion paints to highlight the shape and texture of the rocks.

Step 9: Add static grass and foliage

The final step is to bring your hills to life with a bit of greenery. Static grasses in different lengths and shades can be applied using a static grass applicator, layering the different lengths to give a realistic finish.  We used Straw, Kahki and Evergreen shades of static grass in different lengths to achieve the look we wanted. Clump foliage is also good for mimicking brambles and undergrowth.

Add flowers, bushes, bracken and trees as required to add life and realism.

The photo below illustrates all of the steps outlined above in a single diorama, starting with the embankment formers on the left through to a fully detailed embankment on the right with boulders, static grass, daffodil flower tufts and bracken.