Using a plastic primer before paint application can prevent the paint from peeling, especially if the paint is not designed for plastic.
Acrylics work really well on plastic. If the plastic is nice and rigid it will stick well to it. If you're worried about the paint chipping/peeling you can definitely use a spray primer first, paint and then seal with a varnish.
If painting interior plastics, apply a high-adhesion latex stain-blocking primer. For outdoor plastics, spray-prime with specialized primers formulated specifically for adhesion to plastics.
Mod Podge
Mod Podge comes in a variety of sheens and is great for hobbyists. It also comes in both a brush-on and spray-on option, though the brush-on is the more common kind. Pros: Mod Podge is easy to use, inexpensive, and relatively goof-proof.
When spray painting plastic that is soft, like vinyl, a flexible paint is required, and acrylic-based paints and urethane modified acrylic paints adhere better without cracking, flaking, or peeling. Overall, oil-based paint isn't a good spray paint for plastic as it doesn't bond well.
First, make sure you're using a priming solution designed for use with acrylics. This will help to create a smooth surface for the paint to adhere to. Second, avoid using too muchpaint on your brush . Not only will this make it more difficult to achieve even coverage, but it can also make acrylic paint peel and crack.
Since plastic surfaces are smooth, you can use fine-grit sandpaper to add a slight roughness. Sanding down the plastic in a circle or straight line using the 120 to 220 grit will benefit in leveling the surface for the better application of sealant and acrylic paint.
From my interpretation of your question, you are looking for a clear primer or adhesion promoter. PlastiCote makes a product they call clear primer and adhesion promoter. Rustoleum makes a clear primer spray as well. Both products are intended for automotive use, but are claimed to work well on most plastics.
To paint plastic effectively, you must have a good-quality paint and primer that will both ensure you get long-lasting, beautiful results. When it comes to paint for plastic, our experts always recommend Zinsser Allcoat Exterior as the best, especially for the average DIY'er.
Method 1: Use Spray Varnish
First, lay down some old newspapers or anything else to protect surfaces around your work area. Next, hold the can about 12 inches away from the painting and evenly spray the surface. Allow the first coat of sealer to dry completely before applying a second coat.
Surface contamination such as dirt, oil, and grease. Polish residues on the surface, which impair the adhesion of the paint. Excessive movement of the substrate, such as joints, imposing stress on the paint film which can result in cracking which in turn lets in moisture, ultimately resulting in a flaking paint film.
Spray paint works especially well for plastic, but you can use acrylic or enamel/model paint as well. It would be even better if the paint is meant for plastic. Check the label, and look for words such as: "Plastic" or "Multi-Surface."
91% or 99% rubbing alcohol: Can loosen paint on most plastic surfaces except for acrylic. Pine-Sol Original: Safe on plastic and may help remove paint from plastic miniatures if you soak it in the solution for 24 hours. WD-40: Safe on most plastics and may help loosen paint.
Additionally, plastic surfaces are exposed to various environmental factors, such as sunlight, heat, and moisture, which can cause the paint to peel or flake off over time. To prevent this from happening, you need to choose the right type of spray paint and prepare the plastic surface properly.
“The best way to apply spray paint to a plastic surface is to always clean first and then lightly sand the piece if there are loose debris. Then, use Krylon Fusion All-In-One spray paint for the best adhesion!”
Even though there are paints out there with a primer already included, when painting plastic it's a good idea to use a plastic-specific primer first for best adhesion. Do it after the surface is roughed up a bit with sandpaper and cleaned, and apply it in even light coats.
What's the Best Spray Paint for Plastic? Choosing the best spray paint for plastic is a similar approach to choosing the best spray paint for wood. Rust-Oleum Universal and 2X Ultra Cover spray paints are both designed for use on plastic.
I'd seal with either modge podge or some kind of acrylic-based lacquer (don't use anything with oils, it'll wreck the acrylic). paint on smooth acrylic can chip really easily (think how fingernail polish chips).
The shiny surface of plastic is difficult for standard primers and paints to adhere to. Plastic primers and paints have excellent adhesion properties to help combat this. NOTE: You should wait a minimum of 12 months before painting newly installed UPVC.
Additionally, using a primer specifically designed for plastic can significantly improve adhesion. These primers form a sticky base that helps the acrylic paint to stick better and last longer. After priming, applying the acrylic paint in thin, even layers allows for better adhesion and durability.
Tips for Avoiding Wrinkling/Lifting
Not exceeding recommended film builds. Ensuring that drying conditions are favorable before painting. Not exceeding the paint's maximum recoat time either before recoating or after the application. Allowing enamels or urethanes to thoroughly cure before recoating.