The rocker panel is located so low in the vehicle's body and with close proximity to the road, making it prone to damage and rust. Rocker panel rust in some vehicles is caused by poor drainage on the panel itself, causing moisture to accumulate. Other factors could be the salt spread on the roads during winter and the grime thrown off by the tires. Plus, this body part also takes some beatings from off-roading or even from passing over rough roads.
If you cringe at the idea of replacing your vehicle's rocker panels, then you'd better take some time to protect it against rust. Here are some tips in keeping these panels rust-free:
1. Make sure the rocker panel has proper water drainage.
Check the panel and find the drain holes. Make sure these holes aren't blocked or covered. If you think the number of the holes isn't enough, you can drill additional holes at the bottom part of the panel.
2. Check the panel for dings and scratches from time to time.
After off-roading, four-wheeling, or long-distance driving, it is important to visually inspect your ride's rocker panels for dents, scratches, and other forms of damage. If you notice any, have it repaired as soon as possible. Remember that it's located in a critical area of your ride, so once the metal is bare, rust will surely begin.
3. Coat the rocker panel with bumper-coating paint.
To start off, you need to sand down past the panel's clear coat finish and until all the paint has been roughed up. Unless there's a rusted spot that needs treatment, you need not sand too hard to get down to the metal.
Get rid of any wax left on the panel using an ammoniated cleaner; wipe it dry with a tack rag or a cloth. Make sure that the panel and all its crevices are dust free. You can drive away small particles using a hair dryer.
Protect the surrounding area from paint by taping the rocker panel off. It's also wise to put paper under the edges of the tape. Spray 2 to 3 coats of .high-build. primer, and allow each coat to dry for a few minutes before applying the next coat. Then, apply 2 to 3 coats of bumper coating paint. Also, let each coat sit for a while before spraying the next coat. Compared to regular paint, bumper coating can withstand more abuse and has a satin-like finish that's more resistant to paint chipping, making it ideal to such applications.
If you want the bumper coating to be the final finish, then you're done! But if you want your panel to have your ride's original paint color, you need to spray 2 to 3 coats of primer over the bumper paint. Once the primer has dried, lightly sand it using 400-grit sandpaper before applying 2 to 3 coats of paint that matches your car's original color.
To match the vehicle's finish, spraying 2 to 3 coats of heavy-duty clear coat finish will do the trick. Allow it to dry completely for more than 24 hours before wet sanding the clear coat. You can use 1,000- to 1500-grit sandpaper to wet sand the coat. Apply rubbing compound and car wax, and voila! You now have a rocker panel that's protected from rust!