I purchased the Bulldog adhesion promoter. I have never used it before. I thought perhaps post the plastic media blasting It would make the material porous and the paint may soak in. Perhaps the promoter is enough in this case?
I've used the simple "spray of lacquer" before products such as "Bulldog Adhesion Promoter" came onto the market. and it worked extremely well. Advice from old-time painters of cars from the 60's & 70's instructed me too use Dawn dish soap and scrub the crap out of the plastic parts first (expressing ONLY Dawn basic, not the Fu-Fu fragrant or other brands) and just before shooting lacquer-based color coat, spray an untouched by your hands , solid hit of plain old lacquer thinner followed swiftly (within a few minutes) with the color coat. This works well on vinyl upholstery as well, so long as the mix in your paint is designed for flexing.
My results done in 1979 lasted very well for daily driving. I only shot the kick panels, seats (following a mismatch upholstery job), rear quarter trim (vinyl), doors (metal) and dash (metal). I shot all these pieces at one time with the same flex-mix lacquer upholstery paint.
It took many years (+5 years as a daily driver) to wear through, and then, just some on the front seats, most notably the beading of the upholstery. The plastic parts never scraped through or wore through.
Again, I am trying some repainted areas on other plastic parts for my current project, including the seat back like the original poster is trying to do. The work there is already finished and on the upholstery and plastic parts, including the kick panels, deluxe seat backs (plastic), & upper and lower consoles, I first shot them with a spray of Lacquer thinner but also used the mist of Bulldog.
I guess we'll see in time how well it lasts! I am also using a light Parchment and the seat backs were BOTH Ivy Green. I DID NOT USE PRIMER and they matched very well to the other lighter based items that were already a mismatched parchment.
