Recipe:
I used a movie hulk figure, ground it down in places, dremeled here and there, and sculpted over it with sculpy. I gave it a black base coat, then dry brushed on the silver and gold and sealed it.
The places where the black shows through represents some corrosion of the depleted uranium which forms as a black oxide.
Backstory:
Uranium Man was created as a top secret US Military project, designed to stop Iron Man if he went rogue. Uranium Man's armor was based on stolen design from Stark Enterprises and uses depleted uranium for the bulk of the armor.
Due to the extreme weight of the armor, it is not flight capable, but does feature palm mounted repulsors and a unibeam on the chest.