Carving Out Cave Rocks

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I wanted to have some basic carved cave rocks to mix in with the paper cave walls in the Firefly Caverns. So, I purchased a large sheet of pink insulation foam. There were several brands available at my local Home Depot. Honestly, I just chose the cheapest.

How-To

• First, I peeled off the layer of plastic coating that was on the outside of the board.
• Next, I drew out the rock shapes that I wanted to cut out of the foam.
• Then I used an x-acto knife to cut out the basic shape. The sharper the knife the better. It does make a big difference on the edges of the foam when carving. For me, this was the hardest step. After four hand surgeries, I do not have a lot of strength in my hand, so I did this step in stages to give my hand a break.
• To create the details in the rocks, I tried two different methods.
1. I took the x-acto knife and used the flat edge to scrape horizontal curved lines to create a layered look to the rock. Then I used the pointed end of the knife to scrape out deep vertical crevices throughout the rock to create cracks in the rock.
2. The other method I tried was using a wood burning tool (I kept a glass of water near by to be on the safe side. I don't have the best of luck when it comes to hot surfaces). I used the tool to create cracks and crevices across the rock. I barely touched the surface when I was drawing, because it doesn't take much pressure for the tool to burn through the foam.



Carved with X-Acto knife



Carved with Wood Burning Tool

• After carving the details, I used spray paint to finish up the rocks. I mixed a light flat tan, a glossy brown, and a glossy black. I also used a sandstone spray at the base of the rock. I have heard that the spray paint can eat through the foam. I haven't had this happen, but I would suggest testing your paint on a small surface before you paint your entire rock.

Happy rock carving!