Has anyone found a good way to get a believable concrete color/texture over pink foam? I have tried Floquil cement, aged cement, gravel gray and a couple of Krylon sprays but have not gotten a realistic result. I am trying to build some high bridge concrete supports. Any comments are appreciated.
Try "skim coating" the foam with Hydrocal or plaster of paris, if you can position them horizontally. Then paint them with an airbrush or even a rattle-can.
One key to getting a realistic texture is using a material which reflects light similarly to the material you're trying to model. Foam or styrene is very smooth, even when painted, so the light which hits comes off in a "specular" reflection, much like a mirror. Concrete, on the other hand, is very rough and the incident light is scattered more irregularly. Plaster mimics this surface better.
It takes an iron man to play with a toy iron horse.
Skim coating is very good idea. Regarding the color, concrete colors is always different, and tones may vary depending on the geaographic area it is made. Each geographic area have different kind of agregates (sands, crushed stones, etc..) and each kind have a different color. The best way is to see the real thing and try to emulate the color of the specific prototype (if you have one). In some area concretes are almost pure white due to the use of very white lime stones and white/yellow sands, I've seen concrete made with river rocks and very dark sands that have a coffee or very dark gray color. Some other concretes have a yellowish hue to them (Floquil's). The important thing to have in mind when imitating concrete coloring as that, unless we are talking about a "cosmetic" concrete mix, normal concrete structures never have a solid color, another realistic detail for concrete structures are the mold markings and expansion lines.
Even a good primer coat of flat latex paint over the foam should give you the start for the right texture, and won't be as prone to cracking as plaster.
To get that varied look of real concrete -- sort of blue-gray, sort of light tan, sort of black highlights that you see in the photo above, I use a simultaneously applied two colors of spray paint. Tamiya makes a light aircraft gray and deck tan in spray cans that if sprayed simultaneously gets that varied look so it doesn't look like one basic color. A light spritz later with an alcohol india ink mix should supply the dark highlights you see in the photo above.
The dominant color -- in this case gray -- is applied continuously while the secondary color is applied with bursts as your two hands move back and forth over the work. I find a "waltz" rhythm works well for the secondary color -- ONE two three ONE two three (or in this case SPRAY spritz spritz SPRAY spritz spritz). This might seem like rubbing your tummy and patting your head but a little practice and you'll get it right* -- the point is that both colors go on wet at the same time which creates a natural blending of shades.
I tried, perhaps incoherently, to briefly cover this technique in my "Frugal Modeler" column on concrete sidewalks in the NMRA Midwest Region Waybill a few issues ago. Scroll down to page 4 ...
http://www.mwr-nmra.org/region/waybill/waybil20093fall.pdf
Dave Nelson
* local NMRA division members still talk about the clinic I gave on painting where I tried to demonstrate this "two fisted" spray paint technique. Since I did not want to demo with actual spray paints in a hotel conference room, I used dirt cheap room deodorizing sprays. The smell of peach + lysol nearly cleared out the room before I could finish my clinic. Even I was gagging.
Thank you all for the ideas. I will give them a try and see what happens.
Thanks again, John
in order to get an aged concrete look i have been happy with gray paint, tinted with a bit of yellow. the more yellow you use, the older the concrete looks. i mix in a pinch of talcum powder to kill the shine. this has worked well for me on wood, plaster and plastic.
grizlump
I know you said you tried some of the Krylon sprays, were any of them textured paint? I have some of Rust-o-leum's, American Accents, Sand Stone series rattle cans that gave me a good fine textured look. When weathered should look pretty good as there are several colors you could mix as suggested above. I didn't use it for concrete, but it gave a look that could easily be made to look like concrete. It is a finer texture than some of the others. Also, just to be sure it won't react with the foam, either try it on a sample piece or use a coat of latex paint first.
Good luck,
I thought of something today for concrete on pink foam. Glue sand paper to the pink insulation and paint it. Sandpaper has texture. I'm gonna try that on my new layout for the covered bridge abutments.
I have had good luck with Floquil spray paint. But another option is to use ceiling tile instead of foam board. Glue a stack together and then cut as required with a bandsaw or hacksaw. The texture and natural color is great. Then paint over with a blackwash and you are good to go. I used this method for some bridge piers myself and it turned out great.