I wanted to keep the nacelles from moving up and down while I worked on detailing other areas of the ship so I came up with a solution.
I trimmed four pieces of heavy cardboard to fit above and below the hinges on each side; then I clamped them down tight.
No problem with unauthorized warp drive activation after that!:
I did some light weathering using CreateFX black acrylic wash around the borders of the raised panels on the belly, around the deflector housing,
and the bridge superstructure on top, etc, I had to be careful and wipe it off at just the right time to leave just a trace amount behind.
I didn't want it to get too dirty. It really looks good if you do it right. Detailing really pops too: