Need help with making concrete looking blocks

[Spirit of ob1]

Hey guys currently starting a new project, but basically would any painters be willing to paint some foam to look like concrete slabs?
kinda like this

please let me know

 

[lonepigeon]

You might be able to apply a thin layer of concrete to them.
I saw this trick used on some Lost set pieces in Hawaii. They were built from plywood, but coated with a very thin layer of cement (only about 1/16th of an inch).

 

[berger]

might want to roughen up the surface a bit, and buy some of the rattle cans that are suppose to simulate rock, might be worth a shot

 

[Ramiel]

Easy... I know because I'm doing something... Similar...
Let's make the basic shape, then sand it a bit with rough sandpaper, then spray over it with a rattle can of any color, but only a little mist... little by little, it will eat the foam in small tiny bubbles (bigger, if you don't fully press the nozzle, let it "spit" paint a bit) OR, you could (carefully!) use heat, but this method has less control...
Once everything looks good, seal the surface with a thinned latex paint or something that will not eat the foam and paint it like concrete (it's easier to do than to write it!:lol)
do some tests over a scrap piece of foam first

Or you can use real concrete, OR even some elmers glue and sand (glue the piece like a crazy, cover it with sand, let it dry, and then remove the excess of sand, then a final layer of glue to set it, then paint if needed)

Hope this helps

 

[robstyle]

Concrete is one of the easiest textures to replicate. There are many ways from thickening latex paint and using any form of tool to make the texture (lines, roungh like sandpaper, rocky...) to strait out of the can acoustic ceiling spray and even spray snow. Other things that can be used is spackle, sand and even dirt mixed in with thinned latex paint (for the texture) then repainted for color....
It all depends on how long you need the surface to last.

If you want to spend the money, texture paint should be available by the gallon at Home Depot.


If your dead set on foam, again depending on the texture, latex paint is your magic. One trick with latex and foam is a heat gun but normally thats used for rock surfaces.

 

[JtotheP]

All of the above are great ideas. Another easy step to painting is spatter (spray low air pressure) different values of earthy/concrete colors lightly gives an illusion of sandy texture.

 

[hankey01]

You can also buy textured spray paints. I used one for the base of my T Rex skeleton to make it look like real rock instead of plastic.

 

[coofunkcurly]

I'm planning to do the The Dark Knight suit cage as well. And I'm also planning on using foam. Sealing it and cover with a textured paint is the way I was going to approach it. But I was gonna test a few things on some scrap pieces first.
Good luck! Hope you share the rest of your build with us.

 

[knightoftheroc]

structual foam (the pink stuff, or even the blue) can be lightly smoothed over with portland cement for "real" concrete that's still portable, and won't end up in the basement without warning. You can brush it for trowel marks, if you want, and it can be mixed as thin or thick as you want it to be for working with- you'll get the look, the texture, the actual feel, and even the smell of a real masonry product, and any damage can be realistically patched with another thin coat.

 

[coofunkcurly]

Good tip! Does the surface have a tendency to crack with it being so thinly applied?

 

[Dai Bendu]

Sika makes a product line called Sikatop. It's a polymer modified portland based patch material.

I believe the exact material is Sikatop 123. Which can be used in vertical applications.

It's not too tough to work with. Easier than straight portland cement. and it will stick to almost ANYTHING. Including your tools.

You can't get it at home supply stores. Your local masonry contractor supply should be able to get it. (Rhino materials, or Oldcastle around here)