Welding with flux core wire?

[David_viny]

I have read somewhere that using flux core wire on body panels can cause paint issues. Something to do with the flux leaching out of the weld and effecting the paint. Is this true? I'm thinking of doing some bodywork, mainly rust repair and I have a flux core mig that id like to use. Id rather not rent/buy a gas setup for the mig just to do a few repairs.

Thanks,
-Dave