John H

Try using a piece of a dryer delicates bag. It has a nice, zig zag texture that replicates a carbon fiber weave pretty well. I use Tamiya Rubber Black or Nato Black as a base, then spray Tamiya Gunmetal through the filter bag. If the gunmetal is too bright, you can tone it down with Tamiya Smoke.

Rustoleum, Krylon, etc primer will etch the plastic to give it bite. This makes it really difficult to remove with conventional stripping agents.