Scale Model Structures and Parts
Pine Canyon Scale Models
Diorama Step 2, The plastering process.
Supplies we used for step 2, the plaster process are as follows.
Plaster comes in many forms and several are suitable for our purpose. Most model railroaders use Hydrocal for its hard, durable qualities. However, it can be hard to find. Most concrete and brick facilities have it on hand to sprinkle over the surface on freshly poured concrete. Very few home improvement centers will have Hydrocal. Casting plaster is our second choice and is found at the same facility. However, Plaster of Paris is most commonly found at your local home improvement center, so we will use this plaster for this project. It will only take a couple pounds of plaster for this project.
Other items needed are a roll of high-strength paper towels, bucket of water, cheap 2" brush, medium sized mixing bowl and a can or cup to measure dry plaster.
Tear about 20 of the paper towels from the roll into individual sheets.
Using masking tape, cover details such as retaining walls to protect them from the plaster.
Pour about a cup and a half of dry plaster into the mixing bowl.
Add water and mix using your hands (assuming that you don't have an allergy to plaster).
You can mix with a tool, but it will waste time and we must move very fast, because the plaster will start to set when you least expect it. Mix the plaster to the consistency of soup. Or extremely thin pancake batter.
Using both hands, dip a paper towel into the plaster, making sure it is fully saturated.
Lay the plaster soaked paper towel over the carved foam to form the hills. Smoothen at the edges and remove the air bubbles. For this small area, we folded the plaster soaked paper towel in half to double the strength. Wash your hands in the bucket often. I hang a hand towel from my back pocket for convenience.
Continue the process with additional paper towels overlapping as you go. Adjust the shape as desired.
Scrape any plaster from the areas to that you wish to remain flat.
Once the paper towel process is complete, mix a bowl of plaster to the consistency of pancake batter. This time not thin, but just like you are going to pour pancakes. Working very fast and using the cheap 2" brush, apply plaster over the entire hill area. Brush horizontally to represent wind-blown earth. Clean your brush often or it will be set-up.
We mixed a thick batch of plaster and applied it with your fingers in a vertical blob to form eroded earth as shown in the center of this photo. Once the plaster has started to set, scrape in a vertical motion, using a nail or the edge of the saw. Make many scrapes at the hillside. Using a whiskbroom, tamp the eroded hillside detail to give texture. Once you can no longer carve the plaster, brush vertically with the whiskbroom to clean the eroded detail of loose plaster shavings.
There is no set way for earth to be shaped. Just have fun and experiment until the scene looks the way you want. Think wind and water. Make washes and eroded areas. If you don't like what you see, just scrape it off and start over. It's cheap and fun.