Spalled Concrete - Take 1

I was playing around yesterday with creating what looks like spalling in concrete. I’ve titled this "Take 1' since this is the first try at this and can very well use input from others to improve the process.

Select Your Material

I used Styrene since I had some on hand. Cardstock might be used - in fact it would be easier to work with the only caveat being that you would have to take into account that water based coloring might warp the cardstock. 

Cut Out the Spalled Area

I just whittled out a hole in one piece of plastic.

Taper the Edges and Apply Glue

Well, that's what I did. As you can see in this photo that I tapered the edges of the spalled hole. I then placed this piece of styrene over the other piece and dabbed some Modge Podge in the opening. (I used Modge Podge since I had some handy.)

Apply Sanded Grout

You can get this at your hardware store such as Lowes for example. It is intended to be mixed with a binder for grouting tile. It works great for a variety of scale sized aggregate material. I simply set the top piece of styrene to one side and sprinkled the grout on the wet Modge Podge. (I washed the Modge Podge off of the top piece of Styrene. A good reason to use for an adhesive since it is water soluble.)

Set the Spalling and Spray Paint the Top Layer

I used some thin CAA and applied just enough to soak into the spalling to seal it. Next I sprayed a coat of Rust-Oleum Sandstone Fine Textured Paint. This has just enough texture to look like concrete in O scale. Note that I knocked off the excess grout prior to soaking in CAA.

Spray, Glue and Stain

I glued the two pieces of styrene together and then gave an additional overspray of the Sandstone to everything. I only wanted the color on the spalling, not so much of the texture. I then used a little A/I wash to highlight the spalling.

Finishing Up

I was experimenting with using RIT dye as a stain for scenery (don't get on your ties/track as salt in it will rust metal parts) and had a TAN wash made up.  I dribbled that here and there on the surface, letting it puddle and dry. This left some nice brownish stains on the 'concrete'. I then came back with some A/I to highlight bits and pieces.

So, there you have it. Spalled concrete - "Take 1"