Dodgy plastic

Anybody ever had a bit of SV plastics that will not accept paint.
I have cleaned it,rubbed it back,washed it in prepaint thinners,applied primer which just crazes up
Second attempt,taken back to bare plastic,washed in prepaint thinners,primed with plastic primer and after about 2 hours it started crazing again.
Third attempt,back to bare plastic,skimmed with filler,rubbed down, washed off with prepaint thinners,sprayed with plastic primer and after 4 hours it started to craze again but less this time.
I have had no problem with the lowers,tank,front mudguard or hugger.It is the rear plastics on the underside that is the problem so if any experienced sprayers can point me in the right direction I would be thankful.

P.S. I have ensured that the surface is oil and moisture free each time.

[Wideboy]

try again and build up with thin coats. Primer can react with its self in places so in crazing the coats need to be built up with dust coats..... you could seal it over with a dust of lacquer and start again on top of that

i had the same situation as you on my front fender and rear seat panels, i got over the rear panels with dusting but the front fender i sealed with lacquer and went over the top of it as its was just to bad and crazing up really bad

[timwilky]

Use an isolator on it. You don't know what cr@p is in the plastic, especially if somebody has previously sprayed it.

Edit, also use a flex additive for plastics to stop the paint cracking if the plastic is subject to a bit of movement