No more than 2 hours (The duration of The League of Extraordinary Gentlemen as that was on in the background!). A lot of that was messing with post processing in Dogwaffle
The basemesh probably took about 15 min, then the rest on shaping + sculpting, with a good dose of texture map remixing in Dogwaffle again - trying out some colour and effect filters on a simple greyscale texture to add the noise and streaks.
Right near the end I gave the whole body a couple of twists with widget rotate to make it lose that symmetrical look you get from a static mirrored pose.