Buying a new car, the owner often does not even think about what is hidden under the carpet and in the wheel arches. However, it depends on the quality of primary protection how long the body will resist the aggressive effects of reagents and moisture. Factory anti-corrosion treatment It is a complex multi-stage process that cannot be replicated in garage conditions with the same degree of efficiency.
Many people mistakenly believe that protection is only about painting metal. In fact, before a car rolls off the assembly line, its body goes through a series of chemical and physical procedures aimed at creating a barrier between steel and the outside environment. We will analyze in detail what materials and methods are used by modern automakers to prevent rust.
In modern operating conditions, especially in regions with a harsh climate and an abundance of deicing reagents, galvanizing And polymer coatings become critical design elements. Understanding these processes will help you better assess the condition of your used car or approach the additional protection of your new vehicle competently.
Phosphate: The Invisible Foundation of Protection
The first and perhaps most important stage of body preparation is phosphation. After the body is assembled from stamped parts and welded, it is immersed in special baths with acid solutions. As a result of a chemical reaction, a thinnest crystalline film is formed on the surface of the metal.
This microfilm has a dual function: it passesivates the metal, stopping natural oxidative processes, and creates the rough structure necessary for perfect adhesion to subsequent layers of soil. No quality. phosphate Even the most expensive paint can begin to peel off at the first mechanical damage or temperature drop.
⚠️ If you see paint bloating when buying a used car without visible foci of through corrosion, this often indicates a violation of phosphate technology or damage to this layer during previous poor-quality repairs.
The quality of this stage depends on the purity of the surface before immersion. Therefore, before chemical treatment, the body undergoes thorough washing and degreasing. Residues of oils or technological lubrication can lead to the formation of "bald spots", where the protective film simply does not lie down, creating future foci of corrosion.
Cathodic electrophoretic priming (KTL)
The next step, which is often called the “heart” of anticorrosion protection, is the application of soil by electrophoresis. The body, suspended on the conveyor line, is immersed in a huge bath with water-soluble soil. Through the body passes an electric current, causing the particles of the soil to settle on the metal uniform layer.
The main advantage of technology cathode-pouring (KTL) is its penetrating ability. The soil gets into all the hidden cavities, spars, rapids and hard-to-reach places where it is impossible to reach by brush or sprayer. It is this layer that provides 80-90% of all body protection from rust.
The thickness of the KTL layer is strictly controlled and is usually between 15 and 25 microns. This is enough to create a reliable barrier, but not so much that the soil becomes brittle. It is important to note that this material has the property of self-healing: if chipping occurs, corrosion products block further spread of rust deep.
After leaving the bath, the body is washed and sent to a polymerization furnace, where at a temperature of about 180-200 degrees Celsius, the soil is baked, turning into a durable, non-porous coating. Violation of the temperature regime at this stage can lead to the fact that the soil will not gain its protective properties.
Galvanizing: Active electrochemical protection
One of the most effective methods used by leading automakers (Volkswagen, Audi, Volvo, Ford) is galvanizing. The essence of the method is that zinc is added to the composition of soils or metal sheets, which is a more active metal than iron.
In the presence of an electrolyte (such as salt water from the road), zinc reacts with oxygen first, sacrificing itself and protecting the steel. This phenomenon is called cathodic. Even if the paint and soil layer is damaged to the metal, zinc will continue to protect the steel around the damage, preventing it from rusting.
| The galvanizing method | Description of the process | Effectiveness of protection |
|---|---|---|
| Hot galvanizing | Immersion of parts in zinc melt at 450°C | Maximum (protection up to 20-30 years) |
| Galvanic galvanic | Electrolytic deposition of zinc from solution | High (protection up to 10-15 years) |
| Zinc-containing soils | Adding zinc powder to paint or soil | Medium (depending on the concentration of zinc) |
There are several technologies for applying zinc. Hot galvanizing provides the thickest and most reliable protection, but it is more difficult to apply to finished bodies of complex shape. The galvanic method allows for a thin but very uniform coating that is often used for external panels.
The Secret to Eternal Bodies
The secret to the durability of premium cars lies in the combination of methods. Often, the outer panels are subjected to hot galvanizing, and the hidden cavities are treated with zinc-containing soils, which in total gives a guarantee against through corrosion for 10-12 years.
PVC-plastic and mechanical protection of the bottom
After applying the base soil and the main layer of paint, the turn of mechanical protection comes. Exactly what is commonly called "anticor", at the factory is the application of the PVC-plastic (polyvinyl chloride) It is a thick, squeezy mass that is applied to the bottom, wheel arches and the lower parts of the sills.
The main task of this layer is not only chemical protection, but also physical. Plasticsole creates a thick cushion that extinguishes the impacts of small stones, gravel and sand flying out from under the wheels. Without this layer, the sandblasting effect would quickly strip the paintwork to metal.
The application is carried out by automated robots that strictly dose the amount of material. An important nuance is that plastisol is not applied to all surfaces. In places where heat removal is required (e.g. exhaust system elements) or where rubber seals are located, the material is not applied.
☑️ Quality control of factory protection
After application, the material is baked in the oven, becoming elastic and durable. It does not crack in the cold and does not flow in the sun, retaining its properties throughout the life of the car. However, over time, usually after 7-10 years, this layer may lose its elasticity and begin to peel off.
Protection of hidden cavities: waxes and paraffins
The most insidious place for corrosion is the hidden cavities of the body: the interior of doors, sills, spars and racks. There is moisture, but there is no air to dry. Special protections are used in the plant to protect these areas. preservative on a wax or paraffin basis.
These materials have a high penetrating ability and displace moisture. They are introduced inside the profiles through special technological holes using long pressure sprayers. After application, the wax freezes, leaving a thin fat film on the walls of the metal.
⚠️ Note: When self-washing the car under pressure, try not to direct the jets of water directly into the drainage holes of the sills and doors at an angle. This can wash the factory preservative out of hidden cavities, leaving the metal unprotected.
The uniqueness of factory waxes lies in their ability to migrate. Even if the coating has been slightly damaged, the material is able to tighten small scratches, providing solid protection. However, this resource is not infinite, and it is the hidden cavities that often begin to rot first on cars older than 10 years.
Comparison of factory and garage processing
Many owners are wondering: do you need to do additional anti-corrosion treatment, if the plant has already done everything? To answer this question, you need to understand the difference between an industrial process and garage conditions. Factory processing is a benchmark that is difficult to beat.
In the garage, it is impossible to reproduce the stages of phosphation and electrophoresis. Garage craftsmen usually offer only mechanical protection (mastics, bitumen) or treatment of hidden cavities by Movil. Bituminous mastics, popular in garages, often work as preservatives, but if applied incorrectly can lock moisture under themselves, accelerating rotting.
Factory materials (KTL-soils, plastizols) are designed to work in a pair with paint coating and undergo strict tests for aging. Garage compounds often have a different chemical basis and may conflict with factory materials or simply be less durable.
If you are planning additional processing, use only modern synthetic formulations (e.g. polymer-based) that are vapor permeable. Avoid “cannon bacon” and clean bitumen on new cars – they can disrupt the work of factory protection.
Duration of service and need for updating
How long does the factory protection last? Modern cars that have passed a full processing cycle, including galvanizing, are able to resist corrosion for 10-15 years or more without the appearance of through holes. However, this does not mean that in 10 years the car will not rust at all.
The first usually suffer places of chipping, scratches and mechanical damage. Also, the protection life is reduced due to constant vibration, temperature changes and aggressive chemistry on the roads. Rubber thugs Plastic linings that are stuffed with dirt are also risk areas.
The optimal solution for the owner is a regular inspection of the bottom and hidden cavities, starting from 5-7 years of operation. If the factory plastisol is intact, it is enough to simply clean it from dirt. If you see the detachment or foci of rust, local repair and restoration of the protective layer is required.
Factory corrosion protection is a complex system where each layer performs its function. Preserving its integrity is more important than applying additional “super-means” over intact factory coating.
Frequently Asked Questions (FAQ)
Do I need to make an extra anticorer on a new car?
If the car is new and has full electroplating protection, no additional mastication is required in the first 3-5 years. It is enough once every 2-3 years to do the prevention of hidden cavities wax compositions, especially if you operate a car in harsh conditions.
Why do galvanized cars rust?
Zinc protects the metal until it is depleted or until the coating is broken. When deep chips, where both zinc and soil are damaged, steel begins to rust. Zinc can also be washed out in places of constant contact with water and reagents.
What is the best way to treat the bottom after winter?
The best treatment is a thorough washing of the bottom with the removal of salt plaque. If the protective layer is intact, the chemistry is not needed. If there is damage, use zinc repair sprays or polymer sprays designed for local repair.
How much does a factory anticorer serve?
The average effective service life of factory protection is 10-12 years. After this period, it is recommended to diagnose the condition of the hidden cavities and bottom of the specialist, since the resource of preservatives can be exhausted.