How to Apply Clear Coat to Plastic – 5 tips
Posted: January 14, 2019 By: MattM
Plastic; much like metal comes in different grades for different uses. In modern times cars , motorcycles, and just about everything else comes with a significant amount of plastic in its makeup. With cars coming with so much plastic on them you may want to paint or clear coat the plastic to seal up the paint and add a gloss to the surface. The type of plastic can dictate if or how you clear coat the plastic. If the part is a made of a extremely flexible plastic that will see a lot of movement or abuse you may want to apply the clear coat differently than an extremely hard plastic like a delrin. We decided to give a few tips for applying clear coat to plastic down below.
- Clean the Surface- Some types of plastic can tend to be quite porous and hold in contaminates that could ruin your paint or clear coat even after it is cured. Wiping the surface really well with a good cleaner like PRE Paint Prep and a lint-free rag will help assure the plastic is free of any oils, dirt, or road debris that might harm your paint or clear. We’ve also had good luck using a heat gun to warm the surface of the plastic and help “cook out ” anything that is in the pores. Be sure to keep the heat gun on a medium heat temp and don’t sit in one position for too long to avoid damage to the surface.
- Abrading the Surface- No matter the surface, paint and clear coat need a little bit of abrasion to the surface to help it grab and hold. Using a scuff pad or sand paper before painting or priming plastic is a good idea. We suggest using a non woven scuff pad if you don’t want to put any major scratches in the surface. You can also use the woven pad in conjunction with you paint prep cleaner for the first passes to both clean and abrade the surface; wiping the excess residue off after each pass.
- Adhesion Promoter- When applying paint or clear coat to a plastic that flexes a lot or may see abuse where the plastic would flex (a front lower bumper spoiler for instance) we highly suggest applying an adhesion promoter to the surface first. This will keep the paint and clear coat from flaking or peeling off during normal use and even light abuse. Our favorite adhesion promoter for plastic and metal is Bulldog Adhesion Promoter.
- Light to Medium Coats- When applying clear coat to plastic make sure they your first coats are light or medium and not applied too heavily. You want to let the clear coat get a good bit in the first coats and then you can build from there with slightly heavier coats; trying to stay in the recoat window.
- Flex Agent- On extremely flexible plastics you may want to add a small amount of flex agent to the last coats of clear coat you apply. These additives are for clear coats sprayed through a paint gun and need to be mixed according to the flex agent specifications. We suggest spraying some test coats before tackling the job so you know what to expect for gun setup and mixing ratios.