Unlike the classic American cars of the 1950s and earlier, modern automobiles are full of plastic. From door panels to dash pads to the engine cover, plastic is everywhere. While this may be an affordable way for today’s auto manufacturers to build cars, the fact remains that plastic simply does not last as long as metal. Eventually, the plastic components fade and crack, leaving you with the task of replacing it or living with busted parts on your car.
The 1960s saw the biggest change over from metal to plastic. As metal became more expensive and plastic forming technology grew, the automakers quickly grabbed onto plastic as the material of the future. Not only is it cheaper to make, plastic components are much lighter, weighing a fraction of what metal counterparts would. By the 1980s, everything on the inside of a car was plastic. Pop the hood on just about any car made from the late 1990s and you will likely find engine components that are made of plastic. General Motors has even been using composite plastic components inside the engine itself.
There is not much you can do when composite engine components fail, that is usually a replacement item, but interior and cosmetic components are easily repaired if you take the time to work it out yourself. All you need are some a few products that are readily available at any auto parts store.
–JB Weld Plastic Repair, Kwik Weld, or Original epoxy
–Duplicolor Color-Match Interior Paint
-Duplicolor Truck Bed Liner Aerosol
-Duplicolor Adhesion Promoter
-Wax and Grease Remover
We had a pair of sun-bleached plastic door panels from a 1974 Dodge Challenger that were in need of some restoration. Over time, the sun eats away at plastic, eventually it starts to flake off, much like steel rusts. In addition to the crusty surface, one corner on each panel had split. These panels are hard to find and expensive. Repairing the panels costs less than $20 and takes only 3 hours (not including cure times).
The process begins with a quick clean up. The panels were wiped down with some wax and grease remover. You can use window cleaner, or even soapy water, you just want them to be clean before you start.
Next, the crack was located and assessed. For this repair, the epoxy will be added to back of the panel, which makes the final finish much easier.
Using the masking tape, we closed the crack and secured it.
Next, we mixed the JB Weld Kwik Weld. You don’t need much, just enough to cover the repair.
The epoxy was spread onto the crack, pushing it into the split and then the crack was pushed together and taped again to ensure it would stay closed. The Kwik Weld hardens in 6 minutes, fully cures in 4 to 6.
Once the repair was complete, we sanded the panel with the 320-grit sandpaper. Anything coarser than 320 will leave sanding scratches in the final finish. The goal here is to smooth out the oxidized layer, taking off the chalky plastic, leaving the good layer intact.
The sanding action removes some of the grain, though much of it was already gone due to the chalky plastic. We can’t replace the exact grain, but we can get pretty close with spray-on bed liner. Plastic is inherently difficult to paint, so we need to prep it well. First, it is cleaned with the wax and grease remover (you need to use this product for this step).
Next, we sprayed the panel with Duplicolor Adhesion Promoter. This slightly softens the plastic, providing a mechanical bond that the paint needs to stick.
Adhesion promoter requires 2 coats with rest for 15 minutes between coats, and then top coated within an hour.
To recreate the grain, we need a paint that not only is durable, but also formulated for texture. There are many different paints that we could use for texturing. A light gain is best matched with bumper trim paint, but the heavy grain on the Challenger panel needs a larger texture, making the truck bed coating a better match.
The trick to spraying this stuff is to use several light coats, sprayed from 8 to 15 inches away. The distance gives the paint a chance to dry slightly in the air before hitting the panel. This means the droplets vary in size, the result is a simulated grain that mimics the original grain of the plastic.
The bed liner requires a minimum of 3-4 hours of cure time before touching, but you need to wait 24 hours before reinstalling them.
You might notice that the panels are black. Bed liner is always black, which while that works out well for black interiors, it might not fit your tan, red or any other colored interior. All is not lost, however. Once cured, the bed liner can be top coated with any paint to match your interior. That is all there is to this simple plastic repair and refinish project. This process is good for door panels, consoles, A-pillar trim, just about any plastic component that needs repair and restoration.