There are many different ways to weather ballast, some easy and some not so easy, some use simple tools and materials and others use quite complex tools and materials.In this tutorial I have weathered some N scale ballast using a very simple method, using very basic tools and materials just about anyone can try, the results are fantastic and rival even the most complex and technical methods out there.
I use a variety of pastels for colouring the ballast, the brush you use will want to be very soft and flexible. You don't want stiff bristles because it may disturb some ballast even though it is glued down, some bits may be loosened.In the spray bottle is the glue I used to seal the pastel down, Matte medium. Diluted white glue also works exceptionally well.Dilute it 3 parts water to 1 part white glue.
I don't suppose it matters what brand of pastel, these ones are soft pastels. I tried to get a cheap ones because they can be expensive.Just make sure they are dry pastels and not the oil pastels. Oil ones will not work for this.
I start by shaving the pastel with the sharp hobby knife and catch the shavings in the cup or container.
A small amount of pastel goes a long way.
As for color, I try to use colors with low contrast like grey and faded browns as well as black which is great for weathering areas that get used quite a bit.
The application process is quite easy, you'll need to use you brush.The only requirement is that your brush be completely dry, this will make spreading the pastel over the surface of the ballast much easier. A wet brush has potential for good effects but the shaved pastel will act more like paint once wet and will tend to give you much more dense areas of application.
Lightly brush the ballast and work in small sections, pastel dust that falls on the surrounding greenery can easily be removed by blowing it away. A straw can help direct air to the areas you intend to remove the pastel.Just keep brushing it on in small amounts until you get the desired color.In the photo you can see I'm doing the edge, I've already done the center of the track. I'm doing the edge because some of the green color from the scenery leached up and turned some of the ballast green when I first layed and glued the ballast down.
Finally I use the matte medium glue in the mister to seal down the pastel so it won’t rub off, you may find the color will lose some intensity after the matte medium dries, if this is the case just apply some more pastel after the glue is dry and then re-apply the glue.And that's it, I'm pretty happy with the look I got and it was very useful for fixing the green edges.