Modelling using polystyrene foam

Polystyrene packing foam is one of those horrible environmentally insensitive waste products that just happens to make an excellent model railway landscaping material. Not only is it a lightweight alternative to the bygone practice of pouring plaster over papiermache stretched over chicken wire, but it is perfect for shaping all kinds of terrain from rocky outcrops to gentle rolling hills. And best of all, its a modelling material that is as cheap as chips!

Polystyrene packing foam is easy to cut and can be shaped using nothing but your fingernails.

Recently our front loader washing machine broke down and leaked water through half of my apartment, (just 1 month after it's 5 year warranty expired), and about the only joy I garnered from having to rush out and buy a new one was the knowledge that the polystyrene packing foam could be put to good use making rocks around the railway station precinct on my model railroad. Not only is it easy to cut using a standard hobby knife, the polystyrene foam is also easy to shape using nothing but your fingernails.

Only use PVA wood glue when gluing polystyrene, as anything else will just dissolve it before your eyes.

Gluing the cut and shaped sections of polystyrene foam together is a much slower process. I found out the hard way that using anything other than a water based PVA wood glue simply ate through the foam before my very eyes. Apply the wood glue liberally and have a damp Chux cloth handy to wipe up any glue runs. Then leave the glue to dry overnight.

When shaping and adding rocky outcrops, be sure to leave a flat side to make gluing each shape in place easier.

I wanted my railway station precinct to appear as though it was built hard up against a rocky outcrop. So I glued one of the large rock shapes in place so it was overlapping the far end of the station platform. Be sure to leave one side of your shaped round rock flat, as this will give you a base to glue it in place on your layout. Next up I will seal and paint the rock sections using my own secret formula that is guaranteed not to chip, crack or peel. The only thing I have to decide on is the colouring. Do I use a hard grey base to represent granite rocks from the Tenterfield-Wallangarra area? Or do I go with a more earthen base to represent sandstone outcrops found closer to the Hunter Valley and Blue Mountains areas? Anyway, that will have to be a story for another day.

See also; Building bridges using mirrors and Adding some ground cover