Rust is simply the oxidization of iron-based metals. Mild steel is the construction material for almost all car bodies (fiberglass Corvettes, plastic Reliants, and some nice aluminum-bodied cars such as the Alfa Romeo GTA are the exceptions), and mild steel is subject to rust. Depending on the particular composition of the metal used, rust can begin in minutes on any surface exposed to air! A few European automakers in the 1960s and 1970s, purchased their steel from the Soviet Union. That steel had inconsistent composition and as a result, rusts worse than other alloys.

When you begin your bodywork restoration, it’s important to know where to look for rust. You need to check anywhere that water can get into the bodywork and pool. That means checking the rocker areas immediately behind the wheels, the bottoms of doors and fenders, and around the windshield and rear window. Areas around marker lights and taillights are also common rust spots. Inside the car, especially with convertibles, check the floorpans in the driver and passenger footwell and under the front seat(s).

If your car ever lived -even for one winter in a state where they salt the roads in the winter, it’s nearly certain that you’ve got rust. Also, if your car ever lived at the coast, you’ll have salt poisoning and rust.

Rust is often obscured when a car is prepped for resale, so if you can see the rust on yours, at least you know it’s there. A freshly painted car -especially a cheap paint job -often hides rust that will bubble up within a year.

So, what are your options when it comes to fixing rust? There are products that allow you to cover over rust, and putties and fiberglass filler for holes, but in my opinions, there’s only one truly correct solution for a quality restoration: get rid of the rusty metal and replace it.

I believe there’s a place for the POR-15 products when it comes to painting clean metal, and I use plastic body filler like everyone else to smooth minor imperfections. But when it comes to a hole in metal, I’m a purist. And the restoration industry generally makes it easy to do the repair the right way.

Replacement body panels are available for commonly-rusty areas on a wide variety of domestic cars. If you’ve got a Ford Model A, 50s Chevy, or 60s Mustang, you just pick the panels you need out of a catalog. They simply weld in where you’ve cut out the rusty metal. If you’ve got a rare car, or rust in an unusual place, with a little hammer work and a bending brake you can make quality replacement pieces to weld into place.

In my book Automotive Welding: A Practical Guide, which is available through this site, I detail the procedure for cutting and shaping custom replacement panels and welding up smaller holes. Your local community college likely has courses in bodyworking that will give you the hands-on experience you need. And if you don’t feel like hammering your own metal, it simply doesn’t cost that much more to have your car fixed right -at least, not if the rust is limited to the usual areas. A serious rustbucket can get expensive!

When you’re cutting and shaping pieces, keep in mind that patience is your friend. Get your pieces to fit just right, because once you’ve welded them into place, it’s much harder to fix a cockeyed belt line or sill.

The final thing to remember is to be sure you’ve eliminated all the rust. Older cars actually have an advantage here, because the bodies are comparatively simple compared to a later unibody design. With a unibody, you might need to cut into your box sections to “biopsy” the metal in there for rust. Once you’re sure you’ve eliminated rust from your world, you can weld in new metal, hammer out your dents, smooth it all over with a little body putty, protect the backside with POR-15, and then send it out for paint.