My artistic talent is minimal, at best. But, I needed a 2 3/4 inch block wall at the base of my backdrops. I had some scrap pieces of foam 8' long, so I went to work with a ruler, pencil, pen, a can of spray paint, latex paint and craft paint to see if I could come up with something usable.
Here's the foam I started with
To make the horizontal rows, I marked the foam at 3/8" intervals. I repeated this several times along the length of the foam.
I used a pencil with a slightly dull (rounded, not sharp) point to scribe the horizontal lines in the foam
Along the bottom and top of the foam, I marked off 1/2" increments, which would become the vertical edges of the blocks.
With the ruler perpendicular to the horizontal rows, I drew in the vertical edges of the blocks. This was much harder as the pencil point tended to shred the foam. I switched to a pen, which worked a bit better. I'm sure some of the experts who post here will have some suggestions to avoid the tears in the foam I caused.
I continued the vertical block markings across the top row.
I LIGHTLY sprayed the wall with inexpensive flat black paint. The light dusting allowed the solvent in the spray to "eat" the surface of the foam giving it a rough texture like real blocks. (Test scrap pieces! Too much will leave ugly craters in the foam.) Let it dry overnight so all the solvent evaporates.
I painted the wall with dark gray latex paint (mixed from black and white). The actual color is a few shades darker than in the photo due to the proximity of the lights. The area on the left is where the flat black has not yet been covered with the dark gray.
To try to get a grimy look, I mixed white craft paint with water to the consistency of skim milk. I brushed it on and let it sit for a few minutes.
I used an old T-shirt to wipe the excess white wash off the blocks. Too much came off the first time, so I repeated the white wash, let it sit about 10 minutes then dabbed it off gently with the T-shirt.
I have seen many grimy block walls around NYC with white stains on them. That was the look I was going for as the wall is going beneath backdrops of steel mills. The wall is shown below beneath the backdrop. Obviously lots of scenery is yet to come! Blending the toy like accessories with the backdrops will be a real challenge.
