Is there a clear spray that is suitable for use on parts that are to be vacuum metalized?

[Repstock]

I'd like to check my work before sending out parts.

[peteski]

If you are looking for flaws, why use clear?  Primer is usually good for finding defects.

I believe any solvent-based paint (enamel or lacquer) should be safe to use. I don't use water-based acrylics, so I can't comment on those.  Before the parts get metalized, they are sprayed with very glossy clear coat anyway, then another clear top coat is usually applied after metalizing (to protect the few-atoms-thick layer of metal).

If you want to be 100% sure, contact the company that does the metlaizing, and ask them.