Given the time crunch I'm usually under for the terrain commissions, I don't know if I'll get to post another start-to-finish project journal like I did for the Wrath of Kings diorama. The idea of posting a series of short terrain tutorials appeals to me, and there was some positive response to last week's crate tutorial. So, here's another one recreating the style of mesa that I used for the Wild West Exodus table.
Start with stacks of 2-inch insulation foam. Stack them as high as you like for your mesas. When attaching them, use a bead of Liquid Nails construction adhesive around the edge, and some hot glue in the center. The hot glue will provide an immediate bond so you can work without the foam pieces sliding around. Once the Liquid Nails dries (usually overnight) it will create a more permanent bond.
To texture the rocky surface, begin by making horizontal cuts in the foam about 1-inch deep using an extendable knife. Vary the spacing between cuts and angle the blade to make some V-cuts in a few places.
Then, pick at the foam to pull out chuncks and vary the surface.
You can also make some vertical or diagonal cuts to make pulling the foam apart a little easier.
Work the surface to get a nice mix of raised and recessed stones.
As you approach the top, make the horizontal cuts deeper so you can crack off portions of the foam and create some stepped, flat stones.
Here, the stonework is just about finished. The horizontal seams between the pieces of foam have been obscured among the layers of stone cuts, but the vertical seams where the pieces butt together are still visible.
To camouflage the vertical seams, cut a deep section across the seam and pull out a piece of the foam.
Get an appropriately sized piece of foam from the off-cuts and glue it in place so it straddles the gap.
Do this along the length of the seam until it blends in with the rest of the mesa's surface.
Finally, rub your hand gently over the surface to knock off any loose pieces of foam. Any bits that fall off wouldn't have stood up to vigorous drybrushing. Better to get rid of them now than in the middle of painting.
To make freestanding mesas, the same techniques apply. Just stack the foam, and make the cuts all the way around.
When texturing the table with sand and gravel, add some to the tops and "shelves" of the mesas.