Scenic Modelling Tips and Techniques

Some thoughts, tips and techniques, by Roger Joel

As the theme of the Group demonstrations at this year’s exhibition is scenic modelling I thought it would be useful to summarise some of the aspects and techniques that will be covered.

Basic Scenic Forms

Perhaps it is too soon to say chicken wire and Papier-Mache are dead but as far as most modellers are concerned that tried and tested technique has been superseded by expanded polystyrene and Plaster of Paris bandage. With the latter method the end result is considerably more robust and somewhat lighter than the earlier technique. On the Group’s Pine Bluffs layout we have scenic areas using the polystyrene method that are nearly 20 years old and are still not showing signs of wear.

Cutting the polystyrene can be a somewhat messy process but clearing up afterwards just requires a vacuum cleaner. One of the most useful tools is a small to medium sized serrated kitchen knife that has been bent to provide a curved cutting edge. It is probably safer to purchase one from a discount hardware store rather than incur the wrath of the domestic management.

Fixing the polystyrene requires a PVA based glue. Whilst any PVA will work I have recently moved to ‘Solvent free no-nonsense grab adhesive’ from Screwfix which is used with a sealant gun; this is strong, dries very quickly and is cost effective.

Application of the Plaster of Paris bandage is fairly straightforward. Always work in small areas of less than 300mm square, this will ensure the bandage does not ‘go off’ before it can be applied. The amount of plaster contained within the bandage can vary depending upon manufacturer and it is always worth having a bag of plaster handy to sieve over the wet plaster to thicken the plaster layer; this will help to eliminate the bandage weave showing through the final surface.

When it comes to giving the basic ‘scenic form’ an underlying colour some research is always worthwhile. Soil colour can vary greatly from region to region and choosing the right shade of brown will always help in establishing the railways location; whether it is the red coloured soil of Devon or the sandy colour of East Anglia. Matt emulsion is a good medium to choose as this covers well and is relatively inexpensive. One tip is to ensure that you either purchase enough paint in the beginning or buy one that is mixed to a manufacturers code. This should ensure that you have enough paint for the whole layout or are able to replenish with the right shade in the future.

Track and Ballast

For track underlay the Group have tried a number of different materials including cardboard, mount-board and cork; to date we have found that cork is the most robust and lasts the longest. It is easy to cut with a sharp knife and is fixed using the ubiquitous PVA. Most model railway books cover the weathering of track and the application of ballast and the first lesson is to remember to do them in that order, trying to paint already ballasted track is a laborious and time consuming task. There are a number of ‘paint pens’ available for the colouring of rail and sleepers, although if applied before laying the track a brush and matt acrylics will work just as well.

Many books will tell you to lay the track using track pins and wire the layout so that you can carry out test runs prior to finally fixing the track and ballasting. If the track plan is straightforward and you are not trying to jam multiple turnouts (points) into a limited area this is probably not necessary and you can go straight to fixing the track down with PVA. One of the stronger ‘Grab Adhesives’ will work much quicker in terms of the drying time and will have stronger adhesive power than a normal PVA. My advice is to ensure the adhesive is water soluble so that in the future you can use water to remove and subsequently recover the track when the time comes to dismantle the layout to make way for a move or a new project.

There is no doubt that for realism nothing looks more like stone than stone and there is a wide range of appropriately sized and coloured product available from a wide range of suppliers. As with the colouring of the basic scenic form remember to obtain sufficient ballast to cover all the track you intend to lay, including any planned extensions; whilst it is unlikely the manufacturer of the ballast you have chosen will go out of business or cease the product, it is advisable to remember Murphy.

The ballast should be applied ‘dry’ and brushed into the desired position and thickness using a small paint brush. There are also a number of ‘hopper’ based applicators that you push along the track dispensing ballast as it proceeds; after a while you will discover which tool/brush works best for you. Once the dry ballast is in position this should be damped down with ‘wet water’ (water with a few drops of washing-up detergent added) or isopropyl alcohol. These are best applied using a dropper as the force of a hand sprayer will tend to move the ballast. Once wet you can then apply a water/PVA mix (60/30) with a little added washing-up liquid to reduce the surface tension. It is best to be generous with the amount of the mix applied to the ballast as this will ensure that it is fully secured with the glue. One tip to remember, be very carful in the vicinity of points (turnouts), here you do need to be economical with the application of the glue mix as any seepage in to the point mechanism will be difficult to remove especially once dry.

As with all items on a layout completed track and ballast will always benefit from a light over-spray of a weathering colour. Once weathering is complete remember to clean the rail top and inside edge to ensure good contact with the locomotive wheels.

Rock Scenery

Whilst most British image models do not require anything like the amount of rock scenery that can form an important element of a European or American layout the occasional rocky outcrop can make an interesting scenic element on any layout.

Traditionally rocks have been modelled by using rubber moulds to cast ‘plaster rocks’ that are then set into the landscape and coloured with artist’s acrylic or oil paints. Experience has shown that the best plaster to use is genuine plaster of Paris, rather than building plaster. Be aware plaster of Paris will set very much quicker (within a few minutes) and so needs to be mixed and applied in small quantities. When being used for casting rocks I go for a double cream consistency that will pour easily into the moulds. When being used to ’set rocks’ in place and generally filling round them I go for a mix closer to what you would use to fill a wall. Ensure you stir the mix thoroughly before applying or pouring, this ensure the chemical reaction between the water and the plaster is completed before application thereby reducing the likelihood of air bubbles in the mix.

Because we required a lot of rock for a large canyon on the Group’s Pine Bluffs layout and previous experience had shown that large amounts of plaster equates to a significant weight we decided to adopt actual rubber rocks. These are from ‘Cripplebush Valley Models’ in the USA and come in 600 x 24mm sheets which can be cut into sections and attached to the scenic base using good quality PVA. Once in place the edges of the rubber can be blended into the overall scene using some plaster filler. I tend to over apply the plaster allowing it to be sculpted back once it is dry. My favourite tools for this are a set of very small chisels intended for wood turning and available from most hobby tool suppliers.

Whilst the rubber sheet comes ready painted it is easy to blend into the surrounding scenery using artist’s acrylics or oils. It is advisable to apply the colours using multiple thin coats with varying paint mixes in order to achieve a muted and blended appearance.

Static Grass

This is probably one of the most significant advances in scenic modelling in recent years and is a lot easier to use than at first appears. The technique employed by static grass utilises static electricity to charge fibres so that they are deposited ‘end on’ to wet glue. The charge which needs to be at high voltage is generated by an electronic circuit from a standard battery. All applicators have a container to hold the grass fibres, the static circuit and an earth connection. Through experience we have found that an applicator that has an open fibre container that looks very much like a metal tea strainer is very effective when applying the fibres to smaller areas (see picture below). This type of applicator enables you to apply exactly what you want where you want it.


Whilst there are a wide range of applicators available we have found the cheapest work just as well as the most expensive, especially if you are working on an average sized layout. Experience has shown that a model railway baseboard can be more conductive than you would think and in many cases it is not necessary to ‘wet’ the area around the grounding pin. In fact when applying static grass to the Pine Bluffs layout we found that attaching the earth wire to one rail of the track with a crocodile clip in the vicinity of the area being worked on was sufficient to achieve the desired effect.

Whilst you can use an application of static grass to cover the whole of the grassed areas of a layout it also works very well in combination with foam based scenic material.

One good tip is to be very careful in the application of the glue on the surface area that is to have the static grass applied. Remember if there is no glue on the surface the fibres will not fix and if there is glue where you don’t want fibres they will fix. Once the glue has dried the excess fibres can be removed (and saved) by using a vacuum cleaner with an old pair of tights (without the legs in them) over the nozzle.

If you are looking for a very even covering of an area, such as a mown field, then you are probably better of using one of the static mats available.

Once the static grass, foam material or static mat is dry you should then consider a weathering spray from an air brush or a weathering wash. The application should be a very weak mixture and applied sparingly, multiple light applications is much better than one heavy coat as this will enable far more effective blending of the colours. This application will tone down the overall appearance of the scenery and create a more even weathered effect.