Repairing Surface Rust on Your Classic Car or Truck
Regardless of the type of classic car or truck you own, rust is an enemy. The best way to combat it is to catch it early before it has a chance to cause major damage. If left untreated, what was a simple repair can quickly become an unsightly scar on your car. Here are the steps to take to beat the early stages of light body corrosion also known as surface rust.
1. Assess the Rust
In most cases the first sign of surface rust will become noticeable as bubbles in the paint job. Before you begin the repair you need to test the area to see how deep the corrosion is. If it is just surface rust you can easily make the repair without performing any heavy duty bodywork. If the corrosion has eaten through the metal you will need to cut out the infected area and replace it with new metal. Use a pick or a nail to tap on the rusted area. If it goes through the metal it will need to be replaced, if not then you will be able to fix the issue yourself.
2. Remove the Paint
There are two ways to remove paint to repair surface rust. One method is to sand or grind the paint away. The second method is to use a paint stripper. Either way you need to take safety precautions to protect yourself. Eye protection is very important because paint and rust flakes can be very painful if you get them in your eyes. You certainly do not want to breathe them in either so a mask is suggested if you choose to sand off the paint. Using stripper you will want to wear gloves and work in a well ventilated area to avoid breathing in any fumes. For both methods it is a good idea to mask off the damaged area to help protect the good paint from accidentally being damaged.
If you are going to sand the vehicle use 80-150 grit sandpaper to remove the paint. We suggest using an electric sander until you get to bare metal. Sanding by hand will probably take a while and will be a lot of work. Keep a good eye on the area you are sanding to avoid sanding down the metal too much.
The same goes for using a grinder wheel. Be sure you keep a good grip on the drill and watch closely as you grind down the paint to make sure you do not over grind the metal of your body panel.
When using a paint stripper you will want to apply it liberally to the damaged area and then leave it alone for about 20 minutes so that it can do its work. One tip we have is to cover the stripper with a plastic sheet to help reduce the fumes and to help prevent the stripper from evaporating. It will be easy to see when the paint is ready to scrape off. It will bubble up and begin to peel on its own. Use a metal scraper to remove the loose paint from the rusted area. Once the paint is removed you need to wash the area with warm water to help neutralize it. Be sure to read the directions on the paint stripper you purchase as some require a special neutralizer to stop the reaction.
With either method you should be left with bare metal approximately 2 inches around the rusted area. Be sure to do use a fine grade sandpaper to feather the existing paint to the bare metal for a smooth transition. This will provide the best results in the end when repainting the body panel.
3. Get Rid of the Rust
After you have removed the paint, the next step is to remove the rust. You will again need to use a grinder or sandpaper to get the job done. You need to really take your time and work carefully so you do not remove too much metal making that area very thin. You will want to finish off the rust removal with 150 grit sandpaper or higher. The goal is to get the metal as smooth as possible so that the finish will be smooth when you apply the paint.
If the rust left any pits or imperfections in the metal you can use Bondo or a body filler of your choice to smooth out the body panel. If there is any rust that cannot be reached or sanded away you can use a rust arrestor such as Black-Max to treat the rust and stop the corrosion process.
There are other treatment options for com batting rust as well. Rust converters like Rust-Mort and Corroseal are great options. You will need to apply either product with a pint brush and then allow it to completely dry. Make sure that you have completely covered the infected bare metal. These rust converters can penetrate the corrosion and convert it into a polymer that can stop the corrosion process. You will then be able to prime and or paint over the area and rust will not be able to form. If you applied any treatments, be sure to sand it down smooth once it has had the chance to fully dry and cure. You might be best off leaving it to cure overnight just to be sure.
5.Prime and Paint
There are a couple ways to get a good color match for your paint. One way is to bring in a paint chip to a local paint shop so they can give you an exact match. Another way is to get the color from your VIN number, identification plate or from the manufacturer. We suggest the first option as sun and other elements may have cause your paint to fade in color a little over the years and the original paint might not be an exact match today. Another tip is to spend a little extra to buy high quality primer and paint. The final results will speak for themselves.
If you feel confident with the preparation of the body panel, re-mask the area with new paint tape and newspaper to prevent over-spray from getting onto any existing paint on other parts of your vehicle. You will also want to apply paint in a well ventilated area or use a paint breathing respirator to avoid breathing in any harmful paint fumes. You also want to be sure that dust and other debris will not settle on your fresh paint. In all honesty you may want to consider letting a paint shop do this final step unless you are confident in your working environment.
To apply primer you will want to spry on at least 3 thin coats of primer allowing about 10 minutes in between coats. Then allow the primer to fully dry and cure overnight to ensure it is ready for paint.
Lightly sand the cured primer with 400 git sandpaper to get the surface as smooth as possible so the repair will be undetectable. Remove any primer dust by wiping it clean or using high pressured air to blow it away.
You will then apply the paint the same way you did the primer. About 3 thin coats should do the trick. Allow each coat to dry for at least 2 hours before applying the next coat. Consult the instructions on the paint you purchased to see if 2 hours is sufficient. Some paints require more time in between coats. You can add more layers if you feel that it will provide a deeper look. However, if the paint is not an exact match then do not apply too many coats as this will make the repair really stand out. Less is more in this situation.
Allow the final coat to cure for at least 24 hours before you attempt to remove the tape from the paint area. You should then buff the paint area to help it blend in nicely with the existing paint. If you feel it is necessary you can apply a clear coat so that it matches the finish on the rest of your classic car or truck. And finally, be sure that you wait at least 48 hours (some paints require even more time) before washing your vehicle.
We sure hope that these tips help you to stop rust in its tracks and that you can complete this DIY repair with much success!
Tags: Classic Car Rust, Corrosion Repair, Rust Repair, Surface Rust
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