Disturbing rust on a car will usually spread over time as the metal behind it is exposed to air and moisture, causing it to oxidize or corrode. Whether you want to own or sell a car, your vehicle will look cleaner (and valuable) if it is rust free. Therefore, do not hesitate to clean the rust on the car. Getting rid of rusty parts and giving the car a new paint should be done as soon as possible before the rust spreads further
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Method 1 of 2: Sanding and Repainting Rusted Parts
Step 1. Take basic precautions
This method involves the use of a sander and a grinder, which are electrical devices that remove rust and paint into the air. To protect yourself and prevent injury from airborne rust and paint particles, wear gloves, safety glasses, and especially dust mask so that rust and paint particles do not enter the lungs.
For heavy work, wear a respirator instead of a dust mask
Step 2. Cover all the parts you don't want to get dust on
As mentioned earlier, rust and paint particles will float in the air. If you're not careful, these particles can stick to your car, making it look dirty and difficult to clean. To prevent this, cover the unworked parts of the car (use tape and cover paper). Use a tarp glued with painter tape under the car to define your work area and protect the floor.
Cover your car carefully. Do not use newsprint as it can penetrate paint and leave stains. Use genuine cover paper, which is not too porous and impermeable. Also, make sure you tape each edge of the covering paper. Don't just put a little bit of tape on each corner of the paper. Car paint can seep from loose edges
Step 3. Try to cover along the boundaries of the panel
In general, it's best not to stop in the middle of the panel to prevent sharp lines from appearing that make the difference between old and new paint stand out. These lines will not disappear without sanding or adding a clear coat. Therefore, cover the car well from the start to the edges of the panels around the rusty parts and don't go any further inside.
If you are experienced in painting cars, you can try covering the car only up to a few panels before the parts rust. If you know it, try to apply paint blending tactics gradually so that there is no drastic color difference between one panel and another
Step 4. Remove the paint around the rust using a dual action sander (DA)
The DA sander allows you to control the speed of the sander when removing paint. Start at grit 80 and work your way up to 150. Use an 80-150 grit DA sander to remove primer and car paint, as well as any light rust that hasn't fused to the metal. Smooth the surface between the painted and unpainted surfaces.
When you're done, feel it with your hand (don't remove the gloves). Supposedly, the surface of the car now feels smooth
Step 5. Switch to the metal grinding wheel
Next, use a metal grinder to remove any thick rust deposits and visible holes. Use the grinding wheel slowly as it can cause great damage to the car if used carelessly. When finished, apply a rust-removing acid to the area to be treated to remove any microscopic rust particles that remain.
- Usually, phosphoric acid is best suited for this job. You can buy it at an auto shop.
- If you want, use a hole spot filler or a body filler like Bondo to flatten out dents and fill in the spaces where the paint has gone. Finish the filler with sandpaper (use 120 grit paper) to smooth the metal surface. Read more about using fillers below.
Step 6. Prepare the part to be primed
Purchase a primer that is ideal for metal painting and a car paint that matches the color of your car. Both of these kits can be purchased at automotive stores. Available primers may vary. So, read the primer use guide or consult an expert at an auto shop. Usually, the preparation is as follows:
- Wipe the area with mineral spirit or paint thinner.
- Stick the newspaper with tape all around the area up to 1 meter away.
Step 7. Spray the primer thinly and evenly
Spray three coats of primer, and wait a few minutes between each coat to dry. Don't spray too much primer so it doesn't run and drip.
For most primers, you usually need to wait overnight (at least 12 hours) for the primer to dry properly
Step 8. Scrub with 400 grit wet sandpaper
This paper is specially made to sand between layers of paint so that it is smooth and not shiny so that the paint can stick well. Provide a bucket of water to rinse the sandpaper repeatedly so it doesn't get stained with paint. After that, wash the painted area with mild soapy water.
Step 9. Spray a light coat of paint
Spray a light coat of paint on the car, and "let it sit" for 1-2 minutes before spraying the next coat while keeping no paint dripping or dripping. Apply paint over the primer for a pretty color and look.
Allow the paint to dry for 24 hours before removing the plaster on the car. Be patient. If the paint still feels sticky, wait again.
Step 10. Rub the edges of the new paint so that it blends in with the old paint
If needed, apply a clear coat to evenly coat the entire car. Finally, let the paint harden for 48 hours.
Step 11. Wash and polish your car
Now, your car is rust free and ready to drive.
Just in case, never wax your car for 30 days after painting. The scrubbing motion will erode your car's new paint
Method 2 of 2: Using " Filler Patches " (Putty)
Step 1. Sharpen the rusty parts of the car
This method is slightly different from the above, but the principle is the same and is effective for rust that has perforated the car. First of all, use a metal grinder to get rid of all rust. It's a good idea to grind to a flawless spot around rust even if your car gets a hole.
- You have to get rid of all the rust. If you miss even the slightest bit, the metal behind the fresh paint will corrode and cause new rust.
- Don't forget, since you're using a metal grinder, the above precautions also apply to this method. You must wear gloves, safety glasses and especially dust mask to prevent rust and paint particles from entering the lungs.
Step 2. Cover the hole with anti-rust filler
Next, apply filler to the rusty part. You can buy commercial fillers (such as Bondo) at an automotive store for cheap. However, you will have to improvise when working on a large hole. In this case, you need something flat and sturdy so the paint will stick and not rust. Attach the object to the car with a layer of filler and wait for it to dry.
You can use pieces of soda or beer cans to fill holes. Cans are usually made of aluminum which is anti-corrosion and has a protective coating. You can also use a thin sheet of hard plastic
Step 3. Use sandpaper to flatten the patch
Next, use sandpaper to smooth and even the surface of the patch to the body of your car. This process will be long and tedious because you may need to add filler and wait for it to dry while sanding down the hardened filler. That way, you'll keep repeating the filler and sanding until you're done.
- Start sanding with coarse (low grit) sandpaper to smooth out large bumps. After that, switch to medium sandpaper, and finish with fine sandpaper for a very smooth finish.
- Smooth the patch in a slow, steady motion. Machine sanding can damage your patch.
Step 4. Cover the perimeter of your work area
Next, you will need to apply primer and new paint to the patched area. Therefore, you need to cover your car to protect it from primer and paint particles floating in the air. Do not forget to cover the windows and car tires.
It's a good idea to align the edges of your cover with the edges of the car body to cover any minor differences between the new and old paint (unless you're experienced and can blend the two together so they don't show)
Step 5. Apply a primer and continue with car paint
Spray a light coat of primer and let sit for 1-2 minutes before adding the next coat. Leave the primer overnight to dry. After 12 hours, smooth it with 400 grit wet sandpaper so that the paint can stick well. When you're done, spray the car paint in the same method as spraying the primer.
- It's a good idea to scrub the edges of the paint and/or cover it with a clear coat so the color blends in with the old car paint.
- Of course, you have to choose paint that is the same color as the old car paint. There is a special color code for each car which can be seen on the sticker affixed to your car. You need this code to get the same paint color as your old car paint. Usually, a car paint shop can help you find it. However, don't forget that the old paint on your car has faded over time so even if the code is the same, the new paint won't be 100% the same color as the old paint.
Tips
- In addition to the methods above, you can also try using Rust converter, which is a primer designed to be sprayed directly on a rusty surface. Unlike the method above, you don't have to remove rust and paint from your car. Rust converters have two main components, tannins and organic polymers. The organic polymer acts as a protective primary layer, while the tannin reacts with the iron oxide and converts it to ferrous tannate (stable blue/black corrosion product).
- If your car has a lot of rust covering a large area of the body of the car, it's best to hire a professional.
- You can use a non-spray rust converter for small chips, even if the metal still hasn't rusted. Pour a small amount of this product into a paper cup (parts contaminated with rust and excess should be removed). Apply on the edges of the paint that is still good with a toothpick. Wait a few hours for the product to finish reacting and dry before continuing with your work. The car can be driven if the product is dry enough and does not drip. This product will leave a dull black mark and is usually not noticeable, especially if the car is dark in color. You can also cover it with a little paint.
- If the rusted part is on or near the fender, it's a good idea to jack up the car by propping up the back of one of the wheels. This will allow you to tap the dents from the inside, and leave more room for sanding and painting the car.
Warning
- Wear gloves, safety glasses and a dust mask to prevent irritation and injury from rust and paint particles.
- The combustor is explosive so do not expose it to fire or electricity, (including cigarettes) during rust removal work.
- If using phosphoric acid, MAKE SURE YOU READ AND FOLLOW guide on product packaging.
