Surface rust is light, and is the first sign of rusting. It is surface deep and usually forms in scratches or nicks in your paint. It will just look like a bit of rust on the metal. Scale rust is more serious, and it develops after surface rust is allowed to spread. It’s the most serious rust you can address easily at home. It may include some paint bubbling or flaking of rusty metal. Penetrating rust develops after rust goes untreated for a long time. If there are holes in the metal or the rust goes all the way through, the only way to fix it is to cut the affected metal out and weld a new piece in its place.
If you can’t find the paint code on the body of the vehicle, you can often find it on the manufacturer’s website or occasionally in the owner’s manual.
For most minor rust spots, spray cans of paint are sufficient, but if you need to repaint an entire door, hood, or trunk lid, you may want to use an air compressor or secure the help of a bodywork technician.
You may want to wash the entire vehicle to look for any other rust spots while you’re at it. Be careful scrubbing the rusty area, as metal flakes may poke into you as the rust comes up.
Painter’s tape will come back off of the car without leaving any adhesive residue. To tape off large things like a windshield, you can use plastic (like garbage bags) that you secure in place with painter’s tape.
You can purchase metal or plastic paint scrapers from most hardware stores. Keep scraping until all the loose material is off of the rust spot.
It may take a few sheets of sandpaper to get all the serious rust off. Keep sanding until you see bare metal.
Try sanding in small circles along the edge that developed while sanding with the 40-grit sandpaper to create a flat, even surface. You may want to use 220-grit sandpaper after the 120-grit to achieve an even better finish.
Some rust inhibitors may also come as a gel, which you wipe on and then wipe away. Make sure the surface is completely dry before moving on to the next step.
Make sure the entire area is completely clean and dry before moving ahead. You can use towels to help speed up the drying process.
Do not hold the paint can or gun in one place while it’s spraying or it will become too thick and begin to drip. Shake the can periodically between sprays to keep the paint distribution even.
In unusually humid climates it may take longer than 20 minutes for the primer to dry.
The water helps keep the paint cool and lubricated while you sand to prevent burning or glazing it. Make sure the entire area is clean and dry before moving on to the next step.
Keep the can moving as you paint, otherwise too much could collect and result in dripping. Do not wet-sand a base coat of paint.
If it’s especially humid where you are, wait 90 minutes to be safe.
Apply the clear coat in smooth, even rows just like the other paint. You can purchase clear coat from any auto parts store. Read the instructions on your specific clear coat to know how long it takes to dry.
In many areas, you can skip wet-sanding the clear coat and still have an excellent looking paint finish. Hoods, door panels, and trunk lids are some places you may want to wet-sand because paint issues will stand out on large, flat surfaces.
The new paint may be slightly brighter than the old because of sun fading, but the two colors should be nearly indistinguishable. If you notice any issues with the paint, repeat the wet-sanding process to smooth it out.
