I've been working on Angron recently, trying to get him further along before an apocalypse game on the 30th (I'll have a more pics and a battle report for that).
I have been thickening the finger ridges on the wings to make them more defined before I actually sculpt the joint details. I also tore off the armour down his arm and started again, I just didn't like the way it was before; too flimsy.
On top of that I decided on a few changes and extras.
I decided to remove the mask and replace it with the classic Khornate dog muzzle. So I grabbed my trygon and tore its jaws out. Unfortunately I'm not great at sculpting but I've done my best.
I've also decided to turn his fingers into claws and give him plate gauntlets with blades coming out of them. these will come later.
...and here's some size comparison pictures of his chain axe.