When dealing with unknown substrates it is important to carry out an adhesion test on the existing paint before any repainting is attempted.
First of all a mechanical test must be carried out, for instance using a lattice cut and tear-off band.
If the adhesion of the old paint is not acceptable, it must be mechanically removed and new paint finish applied.
If the adhesion is acceptable, then an etch test is performed using 2-component thinners. If no etching can be detected in this test, application of the the paint finish can be started directly.
Otherwise the old paint must be removed and a new paint finish created.
With the help of universal or special plastic primers and with only a few materials complementary to those previously present anyway, the painter can now apply a long-lasting paint finish to all popular vehicle attachments made of plastic.