In last week’s post I shared with you some of the work I have been doing on my new N Scale modules for the Solent Subdivision.  I focused on using homemade rocks to form a river canyon; you can find the post here.  In this week’s post I’m going to share with you a fast and simple way to color and weather your rocks.

The first thing you need to do is get some reference material to help work out what colors your rocks are going to be.  A simple internet search for river canyon or railroad canyon will bring up all sorts of results.  For example here is a link to an image of a river canyon with similar colors to mine.  Typically base colors for rocks will be gray, brown, yellow or red.  This will depend on the geology in the area you are modeling but mostly it will depend on what you want it to look like.

Once you have decided on your color palette you can pick the paints or stains that you will use.  My rock faces will be based on brown and yellow.  Again I have turned to Woodland Scenics but there are plenty of suppliers of scenic paints or you could simply use cheap acrylic paints from a hobby store.  I am using Burnt Umber and Yellow Ocher as my base colors. Raw Umber is another good base color which will give a grayer finish.

If you wanted to add a bit more red into the color palette Raw Sienna is a good choice but be careful as a little goes a long way and you don’t want to overdo it unless you want a strong red all over.

Because the cast plaster rocks and plaster cloth used to join them all together are porous it is better to stain them using a pigment rather than paint them.  This is because the pigment will be soaked up into the plaster and the colors will bleed into each other giving a cohesive look to the color.  Simple paints on their own would give a blotchy look because the color will stay in the area applied under the brush. The colors from Woodland Scenics are called pigments and are designed to be diluted with water; acrylic paints can be used in the same way.  The other main color I will be using is black and for this I have a simple black acrylic poster paint.

Using three separate plastic pots, one for each color, I prepare the pigments.  In the image below you can see I have added just a little Burnt Umber into the bottom of the pot.

Then I have added water to dilute the pigment.  The bottle says to make the mix 1 part pigment to 16 parts water.  I tend to use a little less water with the lighter colors but it is all down to personal taste and you can also get different effects by changing the mix as you go. The main thing is to make sure the water and pigment are all mixed together.

Using an old paint brush or sponge brush, or just a piece of sponge will do, start by dabbing spots of the diluted pigment onto the rocks in a random order.  The technique is called leopard spotting.  You will notice the plaster will instantly soak up the water from the pigment and the color will bleed away from the spot you touched with the brush or sponge.  I started with the Yellow Ocher as this will be my least dominant color.

Then with the next color, Burnt Umber, I filled in the areas around the Yellow Ocher.  When doing this if you think there is not enough Yellow Ocher you can simply go back and add some more.  The main thing is to ensure all the white is covered.  Depending on the type of rocks you are modeling and your color palette you may also be adding in a third color such as Raw Sienna.

Although the rocks are starting to look nice a lot of the details are still looking flat; that is to say the detail in the cracks  and crags are not showing as well as they could do.  Also the the rocks are looking very clean which is not very realistic.  To solve this I use my final color which is the black.  Again I have diluted the paint with water but this time I have done it roughly 1 part paint to 32 parts water.  I say roughly because whenever I do this I always try a little first then add more paint or water until I get it the way I want it.  Diluting it so much will make it into a wash rather than a paint and this is what we need to bring out the detail without eradicating the previous colors.  The wash is also applied with a brush or sponge and will run down into the cracks and crags a little before the plaster has a chance to soak it up.

You can apply more or less of the wash depending on the finished look you are after.  If you think you have added too much and the rocks are now too dark you can simply add more of the other diluted pigments over the top.

It is a good idea to keep stepping back as you work through the process because it can look different when you are not so close.

On the other side of my canyon you can see all three stages from left to right.  When doing large areas of rock in stages it is a good idea to stagger the finish line, this will make it easier to blend everything together.

Stepping back again you can start to see how the colors will work together.

And finally here is a shot with all the rocks painted.  The green is simply an undercoat in the areas where there will be grasses and vegetation but you can see how the overall effect will look.

Although the main rocks are finished the canyon is not.  I still need to add in lots of detail such as fallen rock, known as talus or scree, as well as all the vegetation before finally adding the water.  And I believe there is a small matter of a railroad trestle.

A few weeks ago I shared with you how I cast my own rocks using plaster and rubber or latex molds; you can find that post here.  In this post I will show you how to use the rocks to create large canyons and cliff faces.

For one of my new modules I am constructing a large timber trestle scene similar to the rendering below.

In the scene the Warsash River enters the module from the front and runs downhill to the left, cutting a deep U shaped canyon in the softer rock, leaving a tricky area for the railroad builders to cross.

What makes the crossing even more complicated is the line diverges at this point.  The Solent Sub Division continues to the right while the branch line exits through the back of the module via a rock tunnel cut through the remaining granite.  This gives the module the name ‘The Warsash Wye’.

To give myself as much flexibility as possible with the design of the canyon only the ends and the small island supporting the junction turnout have been made from wood.  The fascia has been cut to follow the contours of the terrain.  The rest will be built up using my home-made rocks and plaster cloth.

The river bed was installed using a thick cardboard  The river drops ten scale feet from entrance to exit and the bed is propped with more cardboard and glued where possible to give a good solid base.  A basic white glue is good for this.

Next the basic structure of the landscape had to be built.  For this I used strips of cardboard from an old box.  I believe McCain oven fries were the flavor of the day!

Even the back of the canyon had some card added up to the wall. The idea is to remove any large flat and square surfaces.  There is no particular science to this; it just needs to be a bit supportive and give the rough shape you want.

To give some stability to the structure another flat timber was added just under the hole in the back of the module where the branch line exits.  The timber was fixed securely to the back board and the cardboard strips could be fixed to it.  In the image below you can also see the timber island for the turnout. There is a Seep point motor under the timber.  The wires for track power were also installed at this point with lots of slack.  They could be added later but it’s easer to do this now.  The white you can see under the card strips on the left is a cube of polystyrene which had been glued to the inside of the fascia.

The strips of cardboard are glued together and I used a staple gun to hold it all together while the glue dried.  Where the strips meet the back board I used the staple gun for speed but still glued the ends to ensure strength.

Once all the card support was in place it was time to add the plaster cloth.  There are many manufacturers of this and I used a mixture of several I had to hand including Woodland Scenics and Mod Rock.  They are all basically the same although you may get a slight difference in color; this however is not a problem. The Mod Rock turned gray untill it had totally dried.

Although it’s lots of fun it can be a very messy activity so I didn’t take any photos of the work as it progressed.  I would also recommend putting some newspaper under the layout because you will get drips.

To apply the cloth you will need bowl of water, a good pair of scissors and be prepared to get your hands wet.

I cut the cloth into strips a little longer than the height of the canyon, then I dipped the strips into the water one at a time. Make sure you fully submerge the strips in the water. Then I draped them over the cardboard structure with each strip overlapping the last, helping to make the scene all one piece as well as strong.  The strips set fairly quickly and the shape of the canyon soon took form.

There is still some more to be added at the tunnel mouth but that will come later.  The deepest part of the canyon is where the river leaves the module and it is also quite narrow which made it a little tricky.  If you end up using lots of smaller sheets or simply adding several to ensure coverage that’s okay.

I put two layers of plaster cloth on some of the larger areas and staggered the joints, which adds to the strength and closes any holes which you can sometimes get when there is not much plaster on the cloth.  I then left the plaster to dry overnight, although it was probably dry within two hours.  At this stage I could simply paint the plaster rocky colors but I wanted to add the texture of a full rock face to the whole canyon.

This is where all the rocks I previously cast come in.

Taking some of the larger rocks I positioned them in ways that I felt looked natural.  This can take a bit of trial and error.  Once things started to fall into place I glued some of the larger ones down with white glue.  Then I was able to build up, adding more large rock castings and filling in around them with smaller ones.

By the time I had positioned rocks up to the level of the tunnel entrance I had also started to build up the cliff face to cover the tunnel.

I used some of the very large rock castings to form the steep canyon walls in the narrow section behind the turnout.

You will notice there are a lot of gaps between the rocks; this will be dealt with shortly but for now it is more important to make sure the rocks are firmly fixed in place.  Again I used white glue.  At this point I try not to get any of the glue on the face of the rocks as this will show when it comes to paint them.

Looking down the canyon the rocks looks rather out-of-place but this is how I intended them to look and once the next step is done they will look a lot better.

From a distance you can start to see how the rock face will look. I also glued in the outcroppings, for example the group to the bottom right of the photo below.  The rock glued to the back wall to the left of the unfinished area will form part of the tunnel opening.

Once all of the rocks are in place, or at least most of them, and the glue has had a chance to dry, it’s time to seat the rocks and blend them all together.  I do this by using more plaster cloth.  I cut the cloth into strips roughly 25mm (1″) wide by 130mm (5″) long, then I dip each strip in the bowl of water and push the cloth into the gaps between the rocks.  Using my finger I smooth out the surface which brings the small plaster particles to the surface and hides most of the fabric.  I keep adding strips untill the rocks all start to blend together.  I try to encircle all the rocks making them look like they are all one big piece.

At this stage I had also finished the top section with the tunnel opening made from rock castings.  I wanted it to look like the railway engineers had cut the rock back to form the opening

Looking down the Canyon now the walls all seem to be part of the same rock formation.

The rocks in the river bed also now seem to be a part of the landscape. And you can almost picture the river cascading down around them.

And again with the other end of the canyon I have placed rocks at the base of the walls and in the middle of the river bed.

There are still a few gaps but these will disappear once I start to color the rocks and add some greenery around the edges and in the cracks.

Overall I think the effect looks good. The next stage is to add some color but first the whole structure needs to dry.

In a later post I will share with you how to color the rocks to finally blend them all together as well as bringing out all the detail of the cracks and crags.

One thing I enjoy making on my model railroad is mountains with tunnels and bridges.  And for that you need a lot of rock.  In this post I am going to share with you how I make my own rocks, boulders, outcroppings and cliff faces.

The rocks I am currently making are for a modular N Scale layout but this process can be used for any scale.  And as with most things in model railroading there are hundreds of ways to do the same thing. This method is just one that I have found which works for me.

I have been asked in the past why I don’t use actual rocks on my layout.  The answer is that real rocks are very heavy and may not be the right colour for the scene that I’m modelling.  And they can be very hard to shape!  The weight is less of an issue for small areas on a fixed home layout and I have used them before, but for modular layouts the lighter you can make them, the better.

To make my rocks I use plaster or filler, depending on where you buy it from.  Different makes of plaster can effect the outcome so it’s worth thinking about what you will be doing with the rocks.  I have used the cheap powder filler from the local DIY store; this goes a long way but is fairly heavy when dry and again for modular layouts this is not so good.  Woodland Scenics make a product called Lightweight Hydrocal, pictured below, which is a plaster that sets fairly quickly and is very light.  This is ideal for rocks and I use it for most of mine.

To cast the plaster into rocks I use moulds.  I have a few commercially available rock models; mine are also made by Woodland Scenics.  They are made of rubber and are designed to be strong enough to be self-supporting but flexible enough to take out the plaster when dry without breaking the rock, although that is a common occurrence. Below is a typical Woodland Scenics mould.

Even though the moulds are reasonably strong with all the added weight of the wet plaster the sides can droop and if you are not careful the fluid plaster will spill out.  To prevent this I sit the mould on a bed of scrunched-up newspaper so, as the plaster is added, it settles down into the paper without tipping over.

The Hydrocal is very easy to mix. I use an old plastic bowl and wooden spoon.  First I add the plaster, about one and a quarter cups.  Then I add half a cup of water.  I mix all the powder in until the whole mix has the same consistency which only takes about a minute.  Then it’s ready to pour into the mould.  I would not recommend making bigger batches as the plaster starts to set fairly quickly and if you need to stop mid pour it might go off in the bowl.

The plaster sets in about an hour but I tend to leave it overnight as it can be a bit soft if removed too soon and breaks easily.  When it is properly set it will be hard and dry. Below are some rocks cast in the mould above.

This is a great way to make rocks but there is a drawback.  If you are putting a lot of rocks in one area you soon run out of different types.  You can use the same rock several times by changing the direction but it can start to show.  Also, having used my Woodland Scenics moulds many times I am very familiar with the rock shape and can easily spot them on other exhibition layouts.

To get around this and to add diversity to my layout I have made my own rock moulds.  This is not as hard as it sounds and Woodland Scenics provide the tools for the job.  They make a liquid latex rubber which can be painted on to real rocks to make a mould.

I collected a selection of rocks based on shape and texture that I wanted for my layout.  I washed all the rocks to remove any dirt and loose material from the surface.

Then, once dry, I painted a fairly thin coat over the rocks top and sides.  A bit of preparation is a good idea when doing this, mainly making sure you have somewhere to put the rock down once you have painted it and also having some water or even better a sink near by to wash off the brush and clean up if required.  Dont expect to use the brush for anything else after this as it will become a rubbery lump.

Making the first coat thin is necessary to ensure the latex gets into all the detail on the rocks and to prevent any air bubbles from getting trapped under the latex.  It also helps the latex set quickly.  I would also recommend only doing a few rocks at a time so the latex in the jar does not start to form a skin.

Once the section of rock I required was covered I placed it in a foil tray to set.  The latex rubber is white as it comes out of the pot but turns a translucent yellow as it sets.

Depending on the thickness the latex will take about half an hour to an hour to set.  Then another coat will need to be applied.

About three to four coats of latex rubber is required to create a good strong mould.  To make a very strong mould layers of gauze can be placed in-between the latex layers; but so far I have not had the need to do this.

Once the final layer has set, I tend to leave this overnight, the mould should then be a uniform colour.

The mould can be peeled away from the rock.  This can be started by rubbing the edge with your thumb.

Once the edge is lifted all around the mould it should peel away completely.

The mould is then ready to be used to cast a rock.  This particular mould only had three thin coats of latex and will need a little support to keep the same shape as the rock. This is actually a good thing as with out the support the mould will flex in a different direction every time I use it, giving me a slightly different rocks.

The plaster is mixed and poured in the same way as before and the final result is a rock similar to the original just as I wanted.

This method can be used on any surface that has the texture you want for your rocks.  Below I have a section of bark collected last year from a tree.  Now that it has fully dried out I will use it to make a mould.

Again the first layer of latex wants to be very thin as the bark details are fragile.

Once all three layers had set I removed the mould and poured in some plaster.

The latex did pick up some of the bark material which consequently ended up in the rock but that doesn’t mater and will blend in nicely when I colour the rocks.

I have used this process on large and small rocks with great success.

Now that I have a big pile of light weight rocks and boulders it’s time to fix them to the layout and colour them, which I will cover in a later post.