Just a few basic diorama questions.

Thanks guys.

Ordinary Styrofoam, such as that found as packing material, home insulation, busted-up ice chests or whatever, is an excellent substrate for diorama use. I collect the small sheets that come as packing material. They are usually about 1/2 inch thick and can be stacked like pancakes, using white glue between layers. They can be broken by hand, cut with a hot-wire cutter, attacked with a Dremel Tool, (though this makes a big mess) or cut with a sharp X-Acto knife. Think in terms of a contour map, stacking each layer with similar shaped curves, until you build-up the desired shape. Once you have a rough shape built up, you can use various mediums to smooth out the contours and add texture to your ground work. Celluclay or other paper mache type products, plaster bandage with plaster of paris overlay, spackle, drywall compound, water-putty, or anything that dries hard and relatively quickly can be used. I prefer to use plaster bandage with a thin plaster of paris shell over styrofoam, as this is the most common method used by Model Railroaders to build large-scale topography that is both lightweight and extremely durable. You don't get to play with it very much as the plaster hardens, so you need to plan out just exactly what you want ahead of time. The plus side is that you don't have to wait a week of the stuff to harden like Celluclay can require, especially if the Celluclay is applied rather thick.

here is what I do ( all learned from Shep Paine ).  Get a thick wooden base,about 3/4",preferably oak and score it with a utility knife in a criss-crossing motion and then seal it with a spray shellac ( Zinsser Bulls Eye Shellac in a can,available at Home Depot,for example ). Lay three to four coats,letting each coat dry for five minutes before the next one. Now use Styrofoam ( the "crunchy" kind  NOT the kind that is used to make ice chests!. You can get this at Michaels or any craft store) to make uneven surface,craters,berms,etc..It carves very easy...Use "Hold the Foam" (about 3 bucks), a thick white glue for Styrofoam,also at Michaels,to glue your foam down to your base. For ground work, I use a few things but primarily Celluclay,which is also at Michaels (see a pattern here?). Get a big mixing bowl,add a big handful of the Celluclay,a few drops of dish soap,some water,a giant dollop of white glue and finally some cheap raw sienna acrylic paint. The consistency should be like mashed potatoes(mmm..mashed potatoes). Have a coffee can with some backyard dirt and a sifter/strainer at the ready. Use a spatula and spread your mixture over the base. Once you have spread out the mixture,and its still wet put some dirt in your sifter and just gently tap it all over where the ground cover is. After that,get some various sized pebbles and other debris and lightly press them into the groundwork,in a random way. Let the groundwork set up for about an hour and then press in your footprints,tank tracks,plant material,etc..It will take about two days,depending on thickness,for the Celluclay to cure..Once its dried,use something like Polly S "Earth" to airbrush or handpaint() the new groundwork. After that,if you want to add anything,like static grass for example,just smear on some white glue and add your grass. Then its a wash with thinned enamel or oil based paint ...do not used water based paint! All of the materials mentioned are relatively cheap and you can get most of them at a well stocked arts/crafts supply store..HTH