“I loaded sixteen tons of number 9 coal and the straw boss said, ‘Well-a bless my soul!'”
-Tennessee Ernie Ford
I understand why most model railroaders dislike ballasting track. It’s a tedious, repetitive process that takes patience and concentration; two traits that I have in short supply. However, much like benchwork and wiring, its a necessary task that when complete will allow me to move on to more enjoyable aspects of constructing The Hills Line.
I’m using limestone paver base, picked up from my local hardware store, for ballast. One bag cost me less than five bucks and will last a lifetime. I know that since this is the same bag I used on the IAIS Grimes Line.
Since it is an organic material, I do bake a batch in the oven to remove any moisture or other foreign matter. 400 degrees for 30 minutes is more than enough. Just don’t use your good cookware for this process.
The limestone base is sifted to screen out the larger pieces. Sometimes I’ll pass the rock through the strainer several times to ensure I’m getting the finest ballast possible.
The result is a scaled-sized, naturally-colored ballast appropriate for HO scale.
Without a lot of concern for accuracy, the ballast is poured out in small doses over the track. One of these years I’ll need to try handlaid track, so I can ballast the ties before laying the rails, which seems to be the only way to keep ballast off the rails.
Then begins the tedious process of spreading and shaping the ballast. I don’t have any additional tips about this step other than what others have already said. I will say that I have a lot more success with a large 2-inch paint brush, but still keep a few foam brushes around as needed.
Once the ballast is shaped, I spray rubbing alcohol as a wetting agent. With limestone paver being organic, it avoids the common issue of floating away when wet. However it does take longer to dry than other materials.
Matte medium is applied using a small pump sprayer. And then the waiting game begins. While the ballast is drying, I double check and look for any loose grains on top of ties or along the railheads. Otherwise I let it set for at least 24 hours.
One argument against using natural material for ballast is that its too uniform in color. I’ll concede that fact, but counter that I can easily weather and detail it as needed. The money saved by not using commercial ballast far exceeds any shortcomings from using natural stone.
Besides, natural stone paver base is ultimately adaptable to other needs. What do I do with the material that’s too big to be sifted for ballast? Use it as talus and rip-rap for along the banks of the Iowa River.