Fausto DeMartini is a SAVAGE! Three hours for a sketch model grenade!! This is what I got in roughly the same time. Booleans, baby! The rounded edge shader option is a HUGE help here.
The wiry bits are render curves i obtained quick and clean by making some polys, beveling them, then selecting a row of verts, make curve, set to render curves, adjust width in RayGL, and voila!
My maerials suck, but hey.. I'm still learning modeling techniques and haven't gone deep into the materials and shader tree options yet.