How to carve a Green Man wall plaque out of xpsfoam

How to carve a wall plaque out of xps foam with a jab saw, craft knife and sand paper

Creating a wall plaque from XPS foam with a jab saw, craft knife, and sandpaper is a straightforward process

. You can achieve precise cuts and detailed textures by working slowly and steadily. 

Cutting and shaping

  1. Mark your design. Use a marker or pencil to sketch your design onto the XPS foam board. For precise, straight lines, use a ruler or straight edge.
  2. Cut the outer shape. Use your jab saw to cut the overall shape of the plaque. A fine-toothed saw blade works best to prevent tearing the foam. Cut slowly with light, gentle strokes and avoid applying too much pressure.
  3. Refine the details. Switch to your craft knife to cut the smaller details and patterns in your design.
    • For clean cuts: Use a fresh, sharp blade. Make several shallow passes over the same line rather than trying to cut all the way through in one pass.
    • For texture: Use a pencil point, a ball of aluminum foil, or a stiff wire brush to press patterns into the foam surface and create a stone-like texture.
  4. Create beveled edges (optional). If you want a more finished look, hold the craft knife at a 45-degree angle to bevel the edges of your plaque. 

Sanding for a smooth finish

  1. Start with a coarse grit. Begin sanding with a coarse-grit sandpaper to refine the shape and remove larger imperfections.
  2. Work up to a fine grit. Use a medium-grit, then a fine-grit sandpaper (180–220 grit) to smooth the surface.
  3. Sanding technique. Use a sanding block to help apply even pressure and avoid creating uneven dips in the foam. Use light, circular motions to avoid creating gouges. 

Sealing and painting

  1. Seal the foam. Before painting, you must seal the XPS foam to protect it and prevent solvents in spray paint from melting the surface.
    • Option 1: Acrylic sealer: Apply an acrylic foam sealer like AK Interactive Foam Texturizer and Sealer.
    • Option 2: Mod Podge and paint mix: Mix matte Mod Podge with a base coat color (e.g., black) until it is a paintable consistency. Apply one or two coats to the foam.
  2. Prime the surface. After the sealer is dry, apply a primer. You can use another coat of the Mod Podge and paint mixture or a compatible spray primer.
  3. Paint your plaque. Once primed, you can paint your plaque using acrylic paints or other compatible paints. Adding layers of different colors and washes can give it a more realistic finish.