Are you willing to share some techniques for how you got the 3d printed parts so smooth and metallic looking?
Step 1: Sand the hell out of it (I printed in PLA, so vapor smoothing was out, and the parts were so tight I didn't want to make them thicker with XTC 3D). On most parts, I did numerous passes, using successively finer grits (150, 220, 320, 600, 800, 1000, 1500, and 2000). For the latch parts, since they were printed flat, I basically just sanded their edges.
Step 2: Airbrush with Alclad II paints. These give the most metal-looking finishes I've seen (their chrome paint is a mouth-watering thing of beauty).
Step 2a: Prime. I used Alclad's Grey Primer and Microfiller (since it was printed in white, and the next step would be black, I used grey so I could see when I got full coverage for both this step and the next one). This was my first time using Alclad's primer, rather than a spray can; I was hoping it would fill in the striations that I hadn't managed to sand out, but I guess they weren't "micro" enough. For best results, go over it with 4000-grit micromesh after it's dry, but I didn't have any and was too impatient to order some and wait for it to arrive.
Step 2b: Lay down Gloss Black base. This is utterly essential for their chrome paint, but it also really helps give their other shiny metals that extra depth. Try not to touch the painted surfaces at all (it'll pick up fingerprints like mad).
Step 2c: For the parts which would eventually be painted blue, I put Bright Silver Candy Base on over the gloss black. As I discovered, this needs to be done in VERY light passes; if it goes on too thickly, it'll craze as it dries, and just doesn't look good at all.
Step 2d: Put on the final color. I used Aircraft Aluminum, Polished Brass, and Candy Electric Blue.
Let each step dry for at least an hour before moving on to the next one (I paint a plastic spoon along with the model, so I can test dryness without touching the actual thing).
Alclad also makes a gloss clear coat, but I've never used it. If I planned on handling the model a lot, I'd probably give it a try.