Why Does Classic Car Paint Crack

A Brief Anatomy Of Classic Car Paint

Paint coating your classic car prevents rust and makes it shine, but it can also crack. Understanding the structure of paint and how it can fail is not only helpful, but it will also help you to understand what can cause cracking.

Paint is a liquid mixture commonly composed of pigments (color), binders (polymers) and solvents (water). What is not seen, however, is the polymers that actually hold paint together. Classic car paint has what are called cross-links between its binders that help hold the liquid in place before drying.

After your classic car is painted, cross-links are broken down with chemical catalysts that depend on the type of paint used. Combining an oxidizer with an organic compound creates breaks in polymer chains so that after drying they create spaces for air to get trapped inside when exposed to moisture or water intrusion as well as oxygen resulting in blistering or cracking of classic car paint. As this reaction happens over time, a couple factors come into play: UV light speeds up this process while elevated temperatures do just the opposite by slowing down oxidation reactions.

Classic Car Paint Is Seldom The Original Paint

Classic car paint is rarely the original paint that came on the vehicle. The factory paint may have been damaged or chipped before the vehicle ever reached its owner. This damage will need the classic car body to be cleaned as well as sanded and repainted.

What Causes Classic Car Paint to Crack?

Modern paint systems and the solvents used to apply them are engineered to maintain a film of hard, clear lacquer on top of the basecoat. Over time this lacquer can become cloudy, oxidize or wax over from sitting in storage, but it won't crack like it does on your old Chevy.

Classic car paint was formulated differently for a different time, using different chemicals that didn't resist water and UV radiation as well as modern paints do. The paint was generally applied much thinner than is typical today (a 1/4" wet film thickness is common), and then rubbed out by hand before allowing it to dry further.

Problem #1: Lack of cross-linkers

Modern paints use cross-linking chemicals to keep them from drying out and cracking; classic car paints don't have this technology. Quality oil-based enamels like PPG's Deltron® will slowly dry over time if they aren't catalyzed with an appropriate catalyst or mixed with enough tackifier (basically very thick paint). Modern enamels are also formulated to be very resistant to water and oxidizing agents, which makes them attractive for vehicle paints, but they aren't as well-suited for classic car use.

Problem #2: Oxidation

High quality modern paint is formulated with additives that attempt to inhibit oxidation before it occurs. This strategy is useless in a car that sits in a garage all summer. Wind, rain, dirt and UV light can cause rapid oxidation of paint before the cross-linking chemicals have a chance to do their job. The result is a vehicle finish that can look "new" one minute, and chalky and dull another.

Finding the source of your classic car paint's cracking problem won't be easy; you may need to take it apart down to the bare metal or measure its thickness if you're not familiar with the company's color identification system (many classic cars have more than one paint code).

Problem #3: Acid rain

Acids in rain can wreak havoc on paint. Rather than forming a film, a coat of basecoat sits on top of the clear lacquer, which is vulnerable to air and water. Over time the clear lacquer cracks and peels off, leaving bare metal underneath. A quality wax job will keep this from happening once, but it happens all too easily otherwise.

Impact Damage and Your Classic Car Paint Finish

When you think about impact damage to classic car paint, most people automatically think about hail damage. However, impact damage comes in many forms - not just in the form of hail and rain storms.

Rock chips can be just as damaging as hail, if not worse - especially if you drive through areas where there are gravel roads or roads with many potholes or other road defects. Road salt can also be quite damaging when it is strewn on paved roads during winter months and then allowed to dry before it is washed off of your car's bodywork and then allowed to evaporate out of your car's bodywork pores with high-pressure water extraction equipment.

Why Did My Clear Coat Crack?

Most clear coat paint jobs were done in the early 1970's and have been offered up to a car's black interior ever since. Before that time, paints were made with a thicker base and therefore had more gloss. As a result, the clear looked like it was factory-applied. The problem is that these paints don't last nearly as long as they once did. Most of today's clear coats are not in their original can, in fact they haven't been used in years (if ever). They lack the durability of their predecessors, which results in windows turning out dull after extended periods of time. In addition to this, clear coats are highly susceptible to chips- whatever happens to the paint on the car will happen to its clear coat as well- especially when working with wet sanding equipment.

What Causes a Classic Cars Paint to Start Bubbling?

If you own a classic car that is starting to have paint bubbling problems, you probably want to know why. Whether it's a small corner of the car or large sections that are affected by the bubbling, this can mean big problems for your classic. The paint on your vehicle is supposed to last for years and years, but when it starts to crack and bubble up, this can mean the end of your classic car.

So what causes his problem in vehicles? There are several factors that can lead to this issue. Rather than being one big problem with your vehicle, there are multiple things that can cause paint cracking and bubbling. These issues include:

Sun Damage – Although many people think of this as just a problem with older cars, the sun's rays can do damage to newer cars too. The UV rays from the sun really damage the exterior of vehicles over time causing them to fade and crack from their original color. Not only does the sun do damage on it own though, but it will also contribute to other problems causing even more cracking than just what would normally happen with time.

What Does the Most Damage to a Classic Car Paints Topcoat?

When you scratch or damage your classic car's paint, the top layer of your automobile's clear-coat finish is damaged. The topcoat serves as the barrier between your car's basecoat and its original factory color. But, what does the most damage to a classic car paints topcoat?

The Sun - Most classic cars are left outside. They're exposed to rain, snow and direct sunlight. All of these elements can damage classic car paint on a daily basis. Without protection against the sun, automobiles receive UV rays that begin to fade the color and weaken the integrity of its surface quickly. A clear-coat finish is supposed to protect your car from these harmful effects, but it will only last as long as it can repair itself. Sooner or later, daily exposure will cause its topcoat layer to crack and peel away. If left alone for any length of time, this problem will persist into permanent damage requiring costly body work repairs or painting entirely by a professional auto body shop in order for you to restore your vehicle back to its original condition..

What Natural Contaminants Can Cause Your Classic Car Paint to Crack?

There are two main categories of natural contaminant that can cause paint to crack in the long term: (1) Atoms and molecules bigger than 1.5 nanometers in size (called ultra fine) and anything larger than that (2) Water or moisture molecules.anything smaller than 0.3 nanometers in size.

Ultra-fine contaminants such as dust and oils are too small to get trapped right at the surface of the paint. They often tend to build up around the edges or any imperfections on the paint surface creating a "flaky" effect on a clear coat finish like below.

How Could Rain Cause a Paint Job to Crack?

Rainwater can get trapped between your classic car's panels and cause rusting which leads to unsightly rust stains on your car's finish. This can also weaken paint as water has a tendency to weaken paints over time due to its corrosive nature.

Can Mud Damage Your Classic Car Paint?

In addition to causing dirt and debris to build up on the paint, mud can accelerate the oxidation process. Oxidation is what causes paint to turn from a shiny paint finish that reflects light, into a dull paint finish that absorbs light. Mud can also reduce the glossiness or shine of the classic car's paint finish.

Can Sunlight Contribute to Cracking Paint on Your Classic Car?

As the years go on, ultraviolet rays from the sun degrade the paint on your car. This can be especially problematic if your car is parked outside. The sun has a profound effect on vehicular finishes as it's composed of UV light and visible light at the same time. While UVA and UVB cause the most damage, UVC rays are completely absorbed by Earth's atmosphere making them much less harmful to paint jobs.

Can Bird Poop Damage Your Paint?

Bird droppings and chemical fallout from pesticides may be the most common causes of classic car paint damage in a car show parking lot.

What to do if this happens?

If this happens while you are out driving your classic car and you cannot wash it off within 24 hours or before returning home, wash it as soon as possible with soap and water to remove any residue.

Can Surface Rust Spread Wear and Tear on My Classic Car Paint?

Rust can be prevented if the paint is glossy and undamaged. Paint cracks can appear on a car's surface when rust starts to form underneath.

The best way to prevent this from happening is to wash your car often and remove any debris from the surface as soon as you see it.

Does it Make a Difference What Paint Protector You Use?

Most popular classic car paints are lacquers. Lacquers require a clear coat of paint over the top for added durability and protection. First it's important to note that the clear coat does not cure like a regular paint does. In fact, it protects much like an invisible "fence" surrounding the paint that keeps moisture out, preventing future damage from occurring. This is why it is imperative to use a quality products which includes flexible solvents and cross linked polymers which cure by electrostatic friction rather than heat.

Is There a Simple Way to Remove Paint Damage?

No - there is no easy, quick and cheap way to remove paint damage from your classic car without proper restorative services. To get the most bang for your buck, it's always best to have the damage professionally restored by an experienced body shop.

Can a Classic Car Clear Coat Be Repaired?

Clear coat can be repaired so long as the surface itself is not cracked or peeling. Many auto body shops will offer minor clear coat repairs, but if you're serious about returning your classic car to show quality condition, you'll need to find a speciality shop that offers this service or learn how to do it yourself.

The first step is learning how to identify clear coat problems in the first place. If your car's clear coat has faded, it usually indicates that UV light has destroyed the chemical resins with which it's been formulated. There are several ways to fix this problem, but if UV damage isn't repaired soon enough, rust and oxidation may set in behind the paint job.

If your clear coat is peeling or flaking off of the underlying paint job, your problem may be more serious - though not necessarily beyond repair. While most paints are very hard and durable once cured (within 5 minutes after application), some solvents cannot hold up well against UV light after application (they dry out within a day).

Can You Sand Strip Clear Coat and Respray?

The short answer is yes, you can strip paint and repaint it. However, a sand-blasting machine or wire brush is very effective for removing paint chips that occur over time.

This whole process can take up to two hours per car to strip a single coat. Complete the process in stages to minimize costs and pain.

What Are the Best Ways to Prevent Paint Cracking on a Classic Car?

The best way to prevent cracking is to avoid it. Paint should be thoroughly cleaned before applying a fresh coat, and excessive moisture and humidity should be removed. Although dry clean towels are most often recommended, they are not always the best choice. Towels made with cotton or microfiber may leave lint and additional residue on the surface of your classic car paint which can take its toll over time resulting in cracking.

Is Claying Good for Paint Jobs?

Claying is a great way to remove contaminates from the surface of your paint job. The issue with claying is that you don't know how you are going to damage the paint as you are removing contaminants. Claying will, by default, cause small scratches in the clear coat layer if not done properly. These scratches appear as vertical lines in the finish of your paint job and are very visible when viewing them up close at an angle (45 degree angle or greater).

Should You Repaint a Classic Car After a Repair?

As long as you've got your bearings on how paint works, repainting a car is reasonable. Just be advised that the proper prep work and primer will require twice as much time and effort as it would if the area were new.

As you know by now, repainting a classic car isn't meant to be some sort of quick fix. It's best to wait until the problem has been diagnosed and remedied; then resume your activities with restored pride in your car's appearance. Doing so will not only save on wasted time and hassle, but it'll keep rust from forming in areas where it didn't have a chance before.

Should You Do a Full Tear Down Before Repainting Your Classic Car?

While a full tear down is the only way to ensure that all surface damage is repaired, doing so will probably cost more than it's worth. Typically, a primer/sealer layer and one or two coats of paint are sufficient to cover small dents and scratches without requiring a complete tear down first.

In terms of paint jobs that need full body repairs, it may be cheaper to restore the car in its entirety as opposed to taking it apart piece by piece; but this is also very time consuming and requires specialized skills if you want it done right.

What are Paint Tint Leaks?

One of the biggest classics car paint issues is leaks in the factory original paint. This is more commonly seen on cars with metal tops. This issue results from a crack in the door or window rubber seal that allows moisture to seep into the car and then through the paint causing this problem. If you have a classic vehicle with a leaky roof, this could be your culprit.

How Can You Fix The Paint Leaks In A Classic Car?

A lot of times, simply repairing leaks, and then repainting an area will be all that's need to restore it to its previous glory. If you're repainting, then you may want to consider stripping the old paint off first before applying a new coat. But if it's just an easy touch up job, find out if anyone has developed an approved touch up paint for your vehicle before you buy some at your local auto parts store (and have it color matched) to be sure that it will work with your classic car!

Is It Possible to Over-Wash Your Car?

Just like with any surface, the more you wash it, the more you will degrade the quality of your paint. The rule of thumb is to only wash your car as much as necessary. If necessary, that might mean once every other month or even once a year depending on how much driving and environmental exposure your car gets.

Should You Try to Buff Out Every Paint Scratch on Your Car?

You may have seen people using polishes or buffers to try and remove every last little scratch from their cars. Usually, this can only be done with clear coats to make them shine again, but it is not recommended on cars with base coats.

The short answer is usually no - you should not polish out every old paint scratch on your classic car. The reason for this is that while a machine polisher or buffer will remove scratches in the surface of your classic car's paint, it can also take off valuable top layers if you are not careful when using one. At the very least, do some research before trying to fix paint scratches on your own in order to find out what methods work best and what kind of tools you need. If you're just going to use a regular buffer and try buffing out scratches yourself, you might wind up doing more harm than good.

Is It Really Possible To Paint A Classic Car In The Garage?

Yes, you can easily spray paint your classic car in your garage. If you have the room, and don't mind paying for extra ventilation equipment (more on that shortly), then that's a good place to start - particularly if you've painted before and know what kinds of fumes are produced by different paints and primer brands.

When Clear Coating Your Classic Car Make Sure You Properly Filter Out Harmful Paint Fumes

If you've ever painted a car, especially a classic car in your garage, you probably know all too well the foul smell and heavy fumes that come along with it. Many of us have probably experienced some pretty bad headaches and stuffy noses as well. Painting indoors offers the convenience of not having to move your vehicle in and out of the elements. However, it also leaves you in a space that is so small and confined that you cannot get adequate ventilation for the solvent-based paint being sprayed. This is a dangerous and toxic situation that any professional body shop or paint shop goes out of their way to avoid.

Of course, there are additional precautions professional shops take to ensure employee safety when spraying paint or any other potentially harmful materials. These precautions include air filtration systems for a controlled supply of fresh air (and fume exhaust) as well as extensive training and precautions for workers.

What Kind of Spray Gun Should I Get?

Professional painters spend hundreds of dollars on spray guns, compressor hoses, and other equipment that's necessary to paint a car. You don't need to spend quite as much, but you should get a decent spray gun. A gun that shoots at least 350-500 psi will cover most jobs. The lower the psi, the less overspray you'll have and the easier your job will go.

Should You Use Primer When Touching Up Your Classic Car's Paint?

Many people believe that primer is necessary when touching up paint. The truth is that many classic cars have spent years outside with very little protection. If your car has been stored in a garage for many years or painted with modern paints specifically designed for outdoor use (such as PPG Deltron®), applying primer may actually cause more problems than it solves.

Does Touch Up Paint Go Bad?

Touch up paint does not go bad if it is used within the time frame recommended by the manufacturer. However, any other product that touches the paint (such as wax, polishes and cleaners) can potentially pose a contamination threat to the paint job if they have been sitting on a shelf for longer than their expiration date.

Should I Bring My Classic Car to a Restoration Shop if the Paint Is

Cracking or Can I Fix It Myself?

A cracked classic car paint can be repaired by a skilled auto body tech who has the equipment and the know-how to do it. However, you can't simply use any old clear coat - it may be ruined at this point, and you'll need to find a source that's still in good condition.

If you're not comfortable with this step, don't fret: simply bring your car in for service at your regular mechanic shop. A well-equipped repair facility should be able to fix any of these issues for you cheaply and effectively. It may take more time than if it were a new car; but if done correctly, it will look as good as new when the work is complete.

How Many Years of Experience Should a Car Paint Technician Have?

Good spray-on paint jobs take a lot of work. To do a good job, the painter must be familiar with the tools and techniques necessary for the job. It takes years of experience to learn all of the tricks of the trade and how to make a car look as good as it can when you're finished. It's not very hard to learn, but don't expect to be able to just pick up spray-on paint work after trying it once or twice. A good painter has been at this for at least five years, if not much more.

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