How to make faux concrete letters out of polystyrene.
To make faux concrete letters from polystyrene, cut out the letters using a hot wire cutter or craft knife, then refine the shape with sandpaper. Next, apply a textured concrete or masonry paint, or a layer of grout, to create the stony texture. Finally, paint the letters with different shades of gray acrylic or latex paint using a dry-brushing technique to mimic real concrete.
1. Cut and shape the letters
- Trace your letter designs onto the polystyrene sheet.
- Use a hot wire cutter for clean, straight cuts, or a craft knife for smaller details, ensuring you keep the tool steady and perpendicular to the foam.
- Smooth any rough edges with sandpaper, progressing from coarse to a finer grit for a smoother finish.
2. Add texture
- Option 1: Textured paint: Apply a concrete texture paint or a textured spray paint according to the manufacturer’s instructions. You may need multiple coats to achieve the desired effect.
- Option 2: Grout or sand: Apply a thick layer of grout onto the letters with a brush, then use a sponge to dab it and create a stone-like texture. Or, coat the letters with a fine-grade sand while the paint or a bonding agent is still wet, as seen in this Polystyrene Letters article.
- Let the applied texture dry completely.
3. Paint the letters
- Once the texture is dry, paint the letters in shades of gray to look like concrete.
- Use a dry-brush technique, applying a small amount of paint to a brush and lightly wiping it across the surface, which highlights the textured details.
- Allow the paint to dry completely.