This is another one of my early customs. Not so proud of it, but he fills out my Hall of Armour nicely.
Used one of those crappy SMC Ultimate Rhino figures, and shaved off the horns and a couple of other bits and pieces.
Sculpted the mask and chest repulsor, and painted it with Citadel Foundation Mechrite Red and Iyamden Darksun (yellow).
I gave him a wash, but he looked way to dull and dirty, so rather than repaint him I used the tiniest dab of silver enamel paint on my finger and massaged it all over the surface of the figure. This gave everything a more metalic shine, and also highlighted a few raised bits in silver, making him look a bit more battle worn.