For the most part, I used a two part epoxy. I'd knead it and smooth it into place. Then, when it was starting to firm up, I scored it with a knife to add splits and lightly pushed fabric against it to get a little more texture.
As for the build, not much to tell. I was bored and had the stuff so I went for it.
Someday I'll get motivated and make the medical table where he was assembled into Vader.