Most craftsman structure kits include some plain pieces of wood to represent concrete foundations and footers. The author describes a simple technique for creating the look of aged concrete using simple acrylic gesso. The footing of this outer canopy wall was also done with this technique. Here is a good example of using less "nooks and crannies" for a smoother, less aged finish.
Easy aged concrete effects from simple acrylic gesso
by Jimmy Simmons/photos by the author
Have you ever seen wood turned into concrete? We're not talking about the Petrified Forest, either. Almost every wood-based craftsman structure kit will include a wooded foundation or footing that is meant to represent a concrete or cement foundation. Most of the time, we simply paint these pieces a concrete color and install them on our layout or diorama. Wood by itself will never resemble concrete, but I've come up with an easy technique to add texture that more readily represents concrete. Acyrlic gesso is a combination of calcium carbonate with an acrylic polymer medium latex, a pigment and other chemicals that ensure flexibility. It is sold pre-mixed and is available from just about any craft store (even my local Super Wal-Mart has it). There are many uses for gesso, I call it "white out" for modelers because it can be used in so many different ways. One of the ways I like to use it is to create aged concrete textures. The following are the steps I use to create concrete from wood for your model railroad or diorama structures... (I also spoke about this technique on the December 2010 Scotty Mason Show podcast.)
I take the piece of wood that I need to make look like concrete and systematically "glop" some gesso on it. Now don't go crazy here... Remember that by applying the layer of gesso, we will be adding to the overall dimension of the piece of wood, so don't add too much. Ultimately I try to envision the end result as I apply an uneven coat. You can even carve cracks and chips into it after it dries.
You can see in the photo below how the wet gesso looks on this foundation. The "nooks and crannies" left behind will resemble a concrete surface when we get done. The piece in the photo may look like there is a ton of gesso on it, but remember we will be sanding it flat. It's the imperfections on the surface after sanding that creates the aged conrete effect, so you'll want to experiment. If you don't want your foundation or footing to look aged, then try to apply a smoother coat without any "nooks and crannies." Let the gesso layer dry completely before going on to the next step.
Once the layer is dry, sand the gesso down to a shape similar to the original piece of wood. Tape down your sheets of medium and fine sandpaper on a flat surface, and apply even pressure as you sand your piece of gessoed wood. Try to round some of the edges as older concrete won't have well defined corners like a piece of wood. Go slowly so as not to remove too much of the gesso as you sand it flat. If you happened to sand off too much or you are just not happy with the results, you can continue to add gesso, let dry, and then sand again until you are happy with the final results.
You can make the imperfections as dramatic or as subtle as you like. Once you are satisfied with the texture of your concrete surface, paint it with your favorite concrete color (I prefer Poly Scale Aged Concrete) followed by the weathering wash. You can also dry brush some regular Polly Scale Concrete to add some highlights as a final step. Congratulations! You have now turned wood into concrete!
Jimmy Simmons is the owner of Monster Modelworks, providing tools and custom model building services for model railroaders.