11/21/23 - I decided I wanted to construct a mountain/tunnel along the back wall on the O gauge portion of the layout. First, this would provide a sort of backdrop to this area of the layout and secondly, it would help break up the long straight-a-way on this part of the layout.
My plan was to carve the tunnel/mountain out of 2" foam board just like I did for the river rock work. I used nearly two 4'x8' sheets of the foam board for this project. The tunnel/mountain is 10' long by 32" high. It was built in four sections so I could create it on my workbench and also so I could remove it for layout maintenance if required.
Here are the first steps of construction. The basic shape was created using a hot wire foam cutter. The various layers were glued together.
Next came the carving of the foam. I used a fillet knife and a pocket knife for most of the carving. It took many hours to carve all four sections. I almost abandoned the project a few times just because I was tired of carving. It's a slow, repetitious process. This is one section after the carving was finished.
After all four sections were carved into rock, I caulked most of the joints to help blend them better. Once the caulk was dry I cut through the section joints with a razor knife.
The next step is to completely cover the piece with a coat of flat latex tan paint. I also brush on some water to dilute the paint and help it flow into the nooks and crannies. Once this is done everything is set aside to dry.
The rock work is then painted with diluted flat gray paint, similar to how the tan paint was applied. And once again, allowed to dry.
Next comes the washing with diluted flat black paint. The coat is allowed to run and cover the entire piece. I vary the paint coverage so nothing looks too uniform. The real deep cuts get a less diluted coat of paint to create more shadows. It's best to start off with a lighter coat, as you can always go back and add more paint. You can also just add more water to an area and work it in with your brush to light up an area.
I also add some spots of brown and raw sienna to help vary the color of the rock. These spots get blended in with water washes as well.
During this step you may get discouraged because the coloring does not look realistic. However, just trust the process it will get better by the end.
I let the pieces completely dry for a couple of days. Then comes the final step of dry brushing some white paint to bring out the highlights of the rock.
I dip a paint brush in flat white paint. I then dab the brush repeatedly on a dry paper towel to remove most of the paint. I take the brush and very lightly brush along the high points of the rock surface. It takes some practice to use just the right amount of paint and pressure. If you do put on too much paint, just dab the area with a wet paper towel to remove some paint and blend everything together.
You can also add some of this highlighting to recessed areas to help them blend better. I do this in the deep crevices as well.
This is my favorite part of the process. This step really makes the colors all blend together creating a very realistic look.
In these next two photos you can see the difference the white dry brushing makes. The first photo is before the dry brushing and the second is after it is completed.
Here are some photos of the completed structure in place on the layout. I still have to make the tunnel portals and I also want to add some light vegetation to the mountain at some point, but so far I'm happy with the result.
This last photo shows the river rock work I created previously with the mountain in the background. Eventually, I will also have a matching rock face with tunnel portals for the standard gauge to go under the O gauge portion of the layout. This way the river rock, Standard gauge tunnel area and the O gauge mountain will have a cohesive look.