Can rusted body be fixed?

What causes car bodies to rust?

Rusting of car bodies is caused by corrosion, which happens when iron molecules in the steel used to make cars react with oxygen in the presence of water. This chemical reaction produces rust, which eats away at the metal. There are a few common causes of rust on cars:

• Road salt – Salt used to de-ice roads in winter can stick to the underside of cars and accelerate rust.
• Ocean air – Cars near oceans are exposed to salty sea mist, which contains chloride that promotes rust.
• Rain and snow – Moisture sits on car bodies and seeps into crevices, enabling rust.
• Neglect – Not washing or waxing a car allows dirt and debris to sit on the paint, trapping moisture against the metal.

Any car exposed to these elements for long enough will eventually start to rust. However, there are steps owners can take to slow the rusting process and keep their cars looking great.

What are the stages of rust damage?

Rust damage progresses through several stages:

Stage 1: Surface Rust

Surface rust is light oxidation that forms first on the exposed metal surface. It wipes off easily and does not structurally weaken the metal. This is the best and easiest stage at which to address rust damage.

Stage 2: Flaking/Bubbling Paint

In stage 2, the rusting becomes more severe and causes the paint to bubble and flake. This indicates that the rust has penetrated deeper into the body. At this point, sanding and touch up paint are not enough – the affected area needs to be scraped down to bare metal.

Stage 3: Scaling/Pitting

With scaling and pitting, the rust has penetrated through the metal, causing it to become flaky. The body shows signs of surface pits, holes and cavities. Sections of the body may need to be cut out and welded at this stage.

Stage 4: Perforation/Holes

In stage 4, rust has penetrated all the way through the metal, causing actual holes and perforations. At this point, the damage is extremely severe and whole sections of the car body may need to be replaced.

Is it worth fixing badly rusted car bodies?

Whether badly rusted car bodies are worth fixing depends on a few factors:

• Extent of damage – Smaller patches of surface rust are cheaper to fix than widespread perforation rust.
• Value of vehicle – It’s rarely worth fixing rust on an older low-value car, but can be for a rare classic or valuable vehicle.
• Cost of repairs – At some point, rust repair costs exceed a vehicle’s worth. Compare quotes to the car’s value.
• Sentimental value – Some owners want to repair a rusty old car that’s been in the family for years, regardless of financial sense.

As a rule of thumb, if rust repair costs exceed around 50% of the car’s market value, it’s probably not financially worthwhile. But there are exceptions, especially for owners emotionally attached to their vehicles.

Can you completely fix a rusted car body?

It is possible to completely fix a rusted car body, but it requires extensive rust repair work:

• Remove rust – The body must be taken down to bare metal, with all rust sanded, scraped or ground away.
• Treat bare metal – A rust converter or etcher is applied to treat and prep the bare metal for new paint.
• Fill damage – Body filler products are used to fill holes, pits and cavities caused by scaling.
• Prime and paint – Several coats of primer prep the body for fresh paint in the factory original color.
• Replace panels – Severely damaged sections may need to be cut out and replaced with new metal panels.
• Prevent recurrence – Regular washing, waxing and rustproofing treatments help prevent the rust from returning.

This extensive rust repair process is labor-intensive and costly. But when done properly, it can return a badly rusted car to a quality comparable to new. The fixed finish can last many years with proper maintenance.

What are the rust repair options?

Here are the main options for repairing or replacing rusted sections of car bodies:

Sanding

Light surface rust can sometimes be sanded down to bare metal with abrasives like sandpaper or a wire wheel. This works best for stage 1 surface rust without flaking or bubbling paint.

Filling

For more severe rust with scaling damage, body filler putty can be applied to fill pits and cavities after sanding down the rust. This helps create a smooth surface for repainting.

Patch panels

Individual rusted sections can be cut out and replaced with patch panels welded into place. These panels are available for common rust spots like wheel arches, rear quarters, and rocker panels.

Full panels

For extensive rust, whole body panels like doors, hoods, fenders etc. may need replacement. This is costly but repairs all damage in one section.

Cutting/welding

Heavily rusted sections can be cut out with an angle grinder or cut-off wheel, then new steel welded in place. This is intensive but repairs the most severe rust holes and perforations.

Step-by-step guide on how to fix rusted car bodies

Here is a step-by-step DIY guide for properly fixing a rusted car body:

Step 1 – Assess damage

Examine the body closely and identify all areas of rust damage. Probe any bubbling paint to see how deep it penetrates. Locate holes or perforations right through the metal.

Step 2 – Remove trim

Remove all trim pieces like moldings, mirrors, lights, handles, strips etc. This allows you to access and fix rusted areas under trim.

Step 3 – Sand affected areas

Use 80 grit sandpaper on a random orbit sander to remove paint and sand rusted areas down to bare clean metal. Abrasive discs on an angle grinder work for severe rust.

Step 4 – Grind or cut away damaged metal

For sections with holes or severe pitting, use an angle grinder or cut-off wheel to cut away the damaged metal. Weld in new steel patches.

Step 5 – Apply rust converter/etcher

Treat any remaining rust and bare metal areas with a rust converter or metal etcher solution. Follow product instructions.

Step 6 – Fill holes and pits

Fill any remaining pitted areas or small holes with waterproof body filler products, layering to build up the area. Sand smooth.

Step 7 – Weld patch panels

Cut out severely rusted sections and weld in new steel patch panels. Grind the welds smooth.

Step 8 – Apply primer

Spray primer over all repaired areas to seal and protect the metal before painting. Use a high fill primer to fill small dents.

Step 9 – Spray paint color coats

Apply several coats of automotive spray paint matching the factory color. Allow proper drying time between coats.

Step 10 – Reinstall trim

With paint fully cured, reinstall exterior trim pieces removed earlier. Affix using factory hardware and fasteners.

Step 11 – Detail and protect

Detail the repaired and repainted areas using clay bar and paint polish. Apply protective wax, sealant or clear bra.

What are the costs to fix rust on a car?

Costs to fix a rusted car can range drastically based on the extent of damage:

• Surface rust sanding – $200-$500
• Section filler repairs – $500-$1500
• Quarter panel replacement – $1000-$2000
• Full panel replacement – $2000-$5000+
• Extensive repairs – $5000-$15,000+

Labor makes up the bulk of these costs. Severely rusted classic cars or rare vehicles can cost far more to restore. DIY repairs are cheaper but take extensive work hours.

Should I just buy a new car instead?

At some point with an older rust-damaged vehicle, it becomes more logical to buy a new car rather than sink money into repairs. Consider this if:

• Rust repairs exceed value of vehicle
• Other mechanical issues are present besides rust
• Repairs would take more than car is worth in labor time
• The fixed car would still be old with dated technology

Weigh the total repair costs against the maximum budget you would spend to buy a newer used car in similar condition. Include the value of your labor time.

How can I prevent rust on a car?

You can help prevent rust by:

• Regularly washing the car
• Quickly cleaning up any road salt residue
• Applying wax or sealant to create a protective barrier
• Using rustproofing sprays/fluids on the underbody
• Promptly repairing any paint chips that expose metal
• Parking in a garage to shield from rain and snow
• Avoiding parking on wet grass or dirt

Prevention is critical because rust is much harder to stop once it gains a foothold. Start with these steps, along with regular underbody inspections, at the first sign of any rust or corrosion.

Conclusion

Badly rusted car bodies can be repaired and restored to like-new condition, but it requires extensive, labor-intensive work. At some point you reach a tipping point where it makes more financial sense to buy a newer vehicle rather than fix the severe rust damage. But for valuable classic and rare cars, the high cost of rust repair can be worth it. With regular washing and protection, you can catch rust in early stages and avoid the need for major repairs down the road.