For the white bases I used sculpey oven hardening clay. I rolled out a strip of the clay and used a sponge to add texture to the top. After baking the strip and it hardening, I then broke it into the pieces I wanted for the bottom half of the base, and glued it to the base. I then I broke smaller pieces off to form the top layers. After the glue set I used Liquitex Basics Modeling Paste to fill in the crevices between the pieces on top to simulate dirt filling in the crack. While the modeling paste was still wet I also used some small ballast and pressed it into the paste for rocks in the dirt. The brown base is made completely out of cork. I cut the pieces to size and used a sculpting tool to dig pieces out of the cork. I think I like the sculpey bases better.
I have also created custom bases for the Deathwing Terminators I was working on, when I began this blog.
For three of these I just picked up some bark that had fallen off of the tree outside my house. Although this is wood I intend to paint it to look like rock. The one on the left I just wrapped a scrap of cork around it. The front base is a chunk of cork, with a sculpey disk on top of it. I used a scultpting tool to carve a Dark Angels chapter symbol into the disk. This wasn't really visible and since I wanted it to be seen in these pictures I gave it a quick brown wash to bring out the carving. aroung the cork I spread some white PVA glue and added the small ballast to fill out the base. Once I am done painting the other three, I will be adding my homemade sawdust flock to the base. I would do it before painting, but I have already tinted it and it looks better added after painting.