How can I stop my car from rusting?

October 7, 2007 1:37 PM

My car's paint is wearing off. I don't care about the cosmetic impact, but I'm worried about rust. What can I do myself (or have done cheaply) that will prevent further damage?

I'll be honest - I don't take stellar care of my car. I bought it used a few years back, and mechanically it's fine. I only wash it once a month or so, though, and have never waxed it or anything like that.

Over the past few months, I've noticed that some areas have lost their finish, and now the paint is starting to go. The surface in these areas is kind of pitted, where some parts of the finish have worn down more quickly than others. (See pictures here: 1, 2, 3)

I'd like to fix this before my car's body starts rusting, but a full paint job is out of the question. I don't really care how the car looks. I just want to make sure that this car lasts for another 3 or 4 years, until I'm out of grad school.

Is there any kind of wax or sealant I can apply myself that will stop this erosion? Is there some kind of treatment that a body shop can do relatively cheaply? I know next to nothing about auto paint, so I'm hoping the hive mind can help me out here. Thanks in advance.

posted by chrisamiller to travel & transportation (12 answers total)

Bondo! Here's how to use it.
posted by BitterOldPunk at 1:50 PM on October 7, 2007

If you really don't care how it looks, check out an auto parts store for touch-up paint. From the look of the pictures, you'll probably need to spray it on. I've seen cans of 'automotive' spray paint before, but I can't vouch for their effectiveness or quality. If you can get it to stick, though, that's most of the battle.

Make sure the surface is very clean and dust-free before painting. Tape off any trim, windows, or other areas you don't want to get paint on. Spray with a light, even stroke to avoid runs and puddling. You're better off applying multiple light coats than one heavy one.
If you've got a garage to put the car in while it dries, you'll be in even better shape.
posted by Shohn at 2:27 PM on October 7, 2007

You could call a body shop and ask if they'd be willing do this for you with the understanding it'll look kind of bad. They might accommodate you, money's money.

At a minimum the process should involve

- sand/wet sand down the oxidized paint areas (should feather the edges so there's no abrupt layering)
- washing, degreasing, and drying
- following the instructions on whatever product you purchase, prime it, paint (check to see if Duplicolor carries your color -- refer to color code, usually located on the driver's side door frame), and clear coat. Lots of wet sanding and specific wait times involved in between each step to ensure proper curing, so those instructions really are crucial on the products.

I guess you could skip the paint step to save a little money, and just have primer and clear coat. Couple cans of paint aren't very expensive, though, and the end effect would look a little less awful.
posted by empyrean at 2:45 PM on October 7, 2007

Luckily you've decided to do something about this sooner, rather than later.

What you are seeing is the original primer coat underneath the finish coat of paint. Ideally you should leave the primer as intact as possible.

Try to get a reasonably close match with a can of spraypaint from the auto supply store (I'd go to Canadian Tire, what would your equivalent be, Pepboys?)

You really don't need to do that much surface prep. Make sure that you have removed any traces of wax or grease (you can buy a can of "wax and grease remover" when you buy the paint.

As shohn said above, mask off any areas that you don't want paint on (i.e windows, trim, sunroof) using painters masking tape and newspaper. Don't use regular masking tape, it'll leave annoying residue on your car. When masking, the easiest way is to run a strip of masking tape along your edge first, and then tape the paper to that strip using another piece of masking tape.

I wouldn't bother with sanding, the spraypaint should bond fairly well if you have cleaned the surface properly.

Don't try to do it all in one coat - again, as previously stated, multiple light coats are better.

Try to avoid doing this in hot hot sun - a cool day or in the shade will allow the paint to dry more evenly.
posted by davey_darling at 2:47 PM on October 7, 2007

I saw this black tar-like stuff at K-mart that claimed you could paint it right over the rust.

from googling: google search.
posted by mecran01 at 3:52 PM on October 7, 2007

Use a brush or roller with slightly thinned RustOleum enamel,it will last and can be sanded and smoothed later.
posted by hortense at 4:15 PM on October 7, 2007

Thanks, guys. I'll look into matching my car's color with some paint (and maybe I'll get ambitious and try to sand it and use some primer first - I'll see how much this all is going to cost).

All I have is an open carport - no garage. Is doing this outdoors inadvisable? Does this stuff dry quickly enough that I won't end up with dust and grime stuck in the paint?
posted by chrisamiller at 4:45 PM on October 7, 2007

Here is a bit more info for you.
posted by hortense at 5:00 PM on October 7, 2007

Rust-Oleum is what my grandfather uses. He just takes a paintbrush and goes at it, in the classic monkey poo brown colour regardless of what colour he's painting over--it looks like ass, but does seem to prevent rust/rust spread.
posted by anaelith at 5:07 PM on October 7, 2007

The open carport will suffice.

Don't expect pro results here. You will be able to get decent results if you take your time and prepare everything properly.
posted by davey_darling at 6:35 PM on October 7, 2007

Do what davey_darling said, but give the area a very light sand with very fine sandpaper (400 or better) first - try not to sand through the primer to bare metal but, if there are a couple of small spots where the metal is bare, it won't matter too much as long as you paint it within 30 minutes or so or it will start to rust.
posted by dg at 7:31 PM on October 7, 2007

"I don't really care how the car looks."

I've painted many a truck with Tremclad and a roller. The formula is different in the US but it'll still get acceptable results.

If you're willing to do a bit of work you can get very decent results using this technique. $50 and no booth and little masking.
posted by Mitheral at 9:05 PM on October 7, 2007