Has anyone used enamel (Humbrol) for repainting?, the reason I ask is I have over 150 Humbrol model paints that are about 30+ years old and 90% have never been opened.

Dose the enamel paint in general react with the plastic models.

I use Testors enamels, and have no problems. If there is a bunch of excess paint or flashing built up on the model, trim it down first, but you should be fine.

Thanks Kyrios, are you using primer or a base coat first or will that thicken up the layers too much.

Definitely use primer. It creates the ideal surface for the paint to stick to the miniature. If you are worried about losing detail just make sure you properly thin thin your paints (water for acrylic and enamel thinner for the enamel). You could also strip the original paint off but personally didn't do it on my repaints and they held detail just fine.

I want to complement the original model with highlighting the mechanical side, trying to bring the machine to life not so much the character inside it, if ya know what I mean...

I used a combination of metallics and matt paints, re-drew the black lines with a 005 Micron #1 Archival ink (acid free) pen and stole a gold metallic pen from the wife for the finer details and Scum logo on the front of ship.

I generally only use primers if I'm doing a light color, like red or white, and then I'll usually use a white one, if I can get my hands on it at the time. Light grey also works.