Painting plastic surfaces can be a tricky task, as many of the usual methods of painting don't work as well on plastic. Before you start, it's important to consider some of the helpful points and tips collected in this short buying guide. Plasticizers can be added to molding resins to increase impact resistance, but they can often decrease paint adhesion just like mold removers do. Some plasticizers will slowly migrate to the surface and soften the interface between the plastic and the paint, leading to a loss of adhesion.
This can result in costly field breakdowns and liability claims later on, long after the part has been put into service. When it comes to choosing the right paint for your project, there are a few things to keep in mind. Acrylic spray paint is a great option for plastic surfaces, as it dries quickly and offers a durable finish that will be resistant to chips after a week of drying. Krylon's Fusion for Plastic is a popular choice, as it is specifically designed for use on plastic surfaces. BEHR PREMIUM spray paint is another excellent option, thanks to its chemically-resistant oil-based formula that adheres to many surfaces, such as wood, plastic, glass and even concrete. Rust-Oleum's oil-based paint spray is specially formulated for use on PVC, polypropylene, vinyl plastics and more.
You'll also need to coat the paint with a sealant to increase its durability, although all acrylic paint will eventually come off the plastic. Spray cans or spray guns are suitable for very large and hard surfaces, otherwise you can continue with the paint roller and, at the edges, with a brush. Set up a work area to paint your plastic objects that is protected from other areas, as spray paint tends to build up too much. Less effective is the use of chemical oxidizing agents in the paint itself to oxidize the plastic surface enough to generate better paint adhesion. Painting plastic miniatures, toys and game pieces will require a much more specialized set of paints, such as the Army Painter miniature painting kit.
Manufacturers such as Rust-Oleum offer quart-sized primer cans (one product is Rust-Oleum's special plastic spray paint) and quart-gallon paints for plastic (such as Krylon Fusion for plastic and Fusion for Brush-On plastic). Shake the can thoroughly and then try spraying sideways, into the air, or onto a piece of waste material, until the paint is sprayed freely and finely. However, for smaller items, spray paints may not be as ideal and it's probably best to use a brush paint. RePurpose acrylic paint is also ideal for those who prefer to see brush marks on the painted plastic object, to achieve a more rustic look and feel.